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authorSergio Carlavilla Delgado <carlavilla@FreeBSD.org>2021-01-25 23:31:29 +0000
committerSergio Carlavilla Delgado <carlavilla@FreeBSD.org>2021-01-25 23:31:29 +0000
commit989d921f5d4ac8d8b7c831c13b8954ad1901be24 (patch)
treea5d768f9af4b55422fdf5b17064879ae1c7ce032 /zh_TW.UTF-8/books/faq/book.xml
parent0cff342f42461c5081b98bce7581f43df319e4f4 (diff)
downloaddoc-989d921f5d4ac8d8b7c831c13b8954ad1901be24.tar.gz
doc-989d921f5d4ac8d8b7c831c13b8954ad1901be24.zip
Migrate doc to Hugo/AsciiDoctor
I'm very pleased to announce the release of our new website and documentation using the new toolchain with Hugo and AsciiDoctor. To get more information about the new toolchain please read the FreeBSD Documentation Project Primer[1], Hugo docs[2] and AsciiDoctor docs[3]. Acknowledgment: Benedict Reuschling <bcr@> Glen Barber <gjb@> Hiroki Sato <hrs@> Li-Wen Hsu <lwhsu@> Sean Chittenden <seanc@> The FreeBSD Foundation [1] https://docs.FreeBSD.org/en/books/fdp-primer/ [2] https://gohugo.io/documentation/ [3] https://docs.asciidoctor.org/home/ Approved by: doceng, core
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-<?xml version="1.0" encoding="utf-8"?>
-<!DOCTYPE book PUBLIC "-//FreeBSD//DTD DocBook XML V5.0-Based Extension//EN" "http://www.FreeBSD.org/XML/share/xml/freebsd50.dtd" [
-<!ENTITY bibliography SYSTEM "../../../share/xml/bibliography.xml">
-<!ENTITY rel.numbranch "2">
-<!-- number of branches that follow in this list --><!ENTITY rel.head "<emphasis xmlns='http://docbook.org/ns/docbook'>12-CURRENT</emphasis>">
-<!ENTITY rel.head.relx "13.<replaceable xmlns='http://docbook.org/ns/docbook'>X</replaceable>">
-<!ENTITY rel.head.releng "<symbol xmlns='http://docbook.org/ns/docbook'>head/</symbol>">
-<!ENTITY rel.relx "12.<replaceable xmlns='http://docbook.org/ns/docbook'>X</replaceable>">
-<!ENTITY rel.stable "<emphasis xmlns='http://docbook.org/ns/docbook'>12-STABLE</emphasis>">
-<!ENTITY rel.releng "<symbol xmlns='http://docbook.org/ns/docbook'>stable/12/</symbol>">
-<!ENTITY rel.relengdate "December 2018">
-<!ENTITY rel2.relx "11.<replaceable xmlns='http://docbook.org/ns/docbook'>X</replaceable>">
-<!ENTITY rel2.stable "<emphasis xmlns='http://docbook.org/ns/docbook'>11-STABLE</emphasis>">
-<!ENTITY rel2.releng "<symbol xmlns='http://docbook.org/ns/docbook'>stable/11/</symbol>">
-<!ENTITY rel2.relengdate "October 2016">
-]>
-<book xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:its="http://www.w3.org/2005/11/its" version="5.0" xml:lang="zh_TW">
- <info>
- <title>FreeBSD 11.<replaceable>X</replaceable> and 12.<replaceable>X</replaceable> 常見問答集</title>
-
- <author><orgname>FreeBSD 文件計畫</orgname></author>
-
- <copyright xml:lang="en">
- <year>1995</year>
- <year>1996</year>
- <year>1997</year>
- <year>1998</year>
- <year>1999</year>
- <year>2000</year>
- <year>2001</year>
- <year>2002</year>
- <year>2003</year>
- <year>2004</year>
- <year>2005</year>
- <year>2006</year>
- <year>2007</year>
- <year>2008</year>
- <year>2009</year>
- <year>2010</year>
- <year>2011</year>
- <year>2012</year>
- <year>2013</year>
- <year>2014</year>
- <year>2015</year>
- <year>2016</year>
- <year>2017</year>
- <year>2018</year>
-
- <holder>The FreeBSD Documentation Project</holder>
- </copyright>
-
-
-<legalnotice xml:id="legalnotice">
- <title>版權所有</title>
-
- <para xml:lang="en">Redistribution and use in source (XML DocBook) and 'compiled'
- forms (XML, HTML, PDF, PostScript, RTF and so forth) with or without
- modification, are permitted provided that the following conditions are
- met:</para>
-
- <orderedlist>
- <listitem>
- <para xml:lang="en">Redistributions of source code (XML DocBook) must retain the
- above copyright notice, this list of conditions and the following
- disclaimer as the first lines of this file unmodified.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Redistributions in compiled form (transformed to other DTDs,
- converted to PDF, PostScript, RTF and other formats) must
- reproduce the above copyright notice, this list of conditions and
- the following disclaimer in the documentation and/or other
- materials provided with the distribution.</para>
- </listitem>
- </orderedlist>
-
- <important>
- <para xml:lang="en">THIS DOCUMENTATION IS PROVIDED BY THE FREEBSD DOCUMENTATION
- PROJECT "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
- BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
- FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
- THE FREEBSD DOCUMENTATION PROJECT BE LIABLE FOR ANY DIRECT, INDIRECT,
- INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
- TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
- USE OF THIS DOCUMENTATION, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
- DAMAGE.</para>
- </important>
-</legalnotice>
-
-
- <legalnotice xml:id="trademarks" role="trademarks">
- <para>FreeBSD 是 FreeBSD基金會的註冊商標。</para>
- <para>Adobe, Acrobat, Acrobat Reader, 以及 PostScript 是 Adobe Systems Incorporated 在美國和/或其他國家的商標或註冊商標。</para>
- <para>IBM, AIX, OS/2, PowerPC, PS/2, S/390, 和 ThinkPad 是 國際商用機器公司在美國和其他國家的註冊商標或商標。</para>
- <para>IEEE, POSIX, 和 802 是 Institute of Electrical and Electronics Engineers, Inc. 在美國的註冊商標。</para>
- <para>Intel, Celeron, Centrino, Core, EtherExpress, i386, i486, Itanium, Pentium, 和 Xeon 是 Intel Corporation 及其分支機構在美國和其他國家的商標或註冊商標。</para>
- <para>Linux 是 Linus Torvalds 的註冊商標。</para>
- <para>Microsoft, IntelliMouse, MS-DOS, Outlook, Windows, Windows Media, 和 Windows NT 是 Microsoft Corporation 在美國和/或其他國家的商標或註冊商標。</para>
- <para>NetBSD 是 NetBSD基金會的註冊商標。</para>
- <para>Motif, OSF/1, and UNIX are registered trademarks and IT DialTone and The Open Group 是 The Open Group 在美國和其他國家的商標。</para>
- <para>Silicon Graphics, SGI, 和 OpenGL 是 Silicon Graphics, Inc. 在美國和/或其他國家的註冊商標。</para>
- <para>Sun, Sun Microsystems, Java, Java Virtual Machine, JDK, JRE, JSP, JVM, Netra, OpenJDK, Solaris, StarOffice, SunOS and VirtualBox 是 Sun Microsystems, Inc. 在美國和其他國家的註冊商標。</para>
- <para>許多製造商和經銷商使用一些稱為商標的圖案或文字設計來彰顯自己的產品。 本文中出現的眾多商標,以及 FreeBSD Project 本身廣所人知的商標,後面將以<quote>™</quote> 或 <quote>®</quote> 符號來標註。</para>
- </legalnotice>
-
- <releaseinfo xml:lang="en">$FreeBSD$</releaseinfo>
-
- <abstract>
- <para>這份文件是 FreeBSD 12.<replaceable>X</replaceable> 和 11.<replaceable>X</replaceable> 常見問答集 ( <acronym>(FAQ)</acronym> )。我們盡可能地讓這份 <acronym>FAQ</acronym> 提供有用的資訊 ; 如果您有任何改善建議,請寄到 <link xlink:href="http://lists.FreeBSD.org/mailman/listinfo/freebsd-doc">FreeBSD 文件計畫郵件論壇</link>。</para>
-
- <para>本文件的最新版本可由 <link xlink:href="https://www.FreeBSD.org/doc/zh_TW.UTF-8/books/faq/index.html">FreeBSD 網站</link>取得。 也可以由 <link xlink:href="https://download.freebsd.org/ftp/doc/">FreeBSD FTP 伺服器</link> 以 HTTP 下載單一大型 <link xlink:href="book.html">HTML</link> 檔或是其他格式的檔案。</para>
- </abstract>
- </info>
-
- <chapter xml:id="introduction">
- <title>前言</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="what-is-FreeBSD">
- <para>什麼是 FreeBSD?</para>
- </question>
-
- <answer>
- <para>FreeBSD 是一個使用於桌機、筆電、伺服器與嵌入式系統平台的現代作業系統,支援多種<link xlink:href="https://www.FreeBSD.org/platforms/">平台</link>。</para>
-
- <para>它是根據 U.C. Berkeley 所開發出來的 <quote>4.4BSD-Lite</quote> ,並加上了許多 <quote>4.4BSD-Lite2</quote> 的增強功能。它同時也間接使用了 U.C. Berkeley 所開發出來並由 William Jolitz 移植到 <trademark>i386</trademark> 的 <quote>Net/2</quote>,也就是 <quote>386BSD</quote>,不過現在 386BSD 的程式碼只剩下極少數還留 存在 FreeBSD 中。</para>
-
- <para>FreeBSD 已被廣泛地被世界各地的公司行號、ISP、研究人員、電腦 專家、學生,以及家庭用戶所使用,用在工作、教育以及娛樂上。</para>
-
- <para>如果想看關於 FreeBSD 更深入的資料,請看 <link xlink:href="@@URL_RELPREFIX@@/doc/zh_TW.UTF-8/books/handbook/index.html">FreeBSD 使用手冊</link>。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="FreeBSD-goals">
- <para>發展 FreeBSD 計畫的目的是什麼?</para>
- </question>
-
- <answer>
- <para>FreeBSD 計畫的目的是提供可以任意使用且沒有限制的穩定快速與一般用途的作業系統。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="bsd-license-restrictions">
- <para>FreeBSD 版權有任何限制嗎?</para>
- </question>
-
- <answer>
- <para>有的。但是這並不是限制你怎麼去使用這些程式碼,而是你怎麼看待 FreeBSD 這個計畫。可以在此閱讀 <link xlink:href="https://www.FreeBSD.org/copyright/freebsd-license.html"> 版權本文</link>,簡單來說總結如下:</para>
-
- <itemizedlist>
- <listitem>
- <para>請勿宣稱是您寫了這個程式。</para>
- </listitem>
-
- <listitem>
- <para>如果它出問題了,不要控告我們。</para>
- </listitem>
-
- <listitem>
- <para>不要移除和修改版權</para>
- </listitem>
- </itemizedlist>
-
- <para>我們許多人在這個計畫投入很多心血,並不會介意獲得一些財務上的報酬,但是我們並沒有堅持一定要有。我們相信我們首要的<quote>任務</quote>是將程式碼提供給所有使用者,無論他們有任何的目的,這麼一來,這些程式碼才能被用在最多地方,也才能發揮它們最大的利益。我們相信這就是自由軟體最基本的目標之一,而且我們會盡全力去支持它。</para>
-
- <para>在我們 source tree 中有部份的程式碼是採用所謂的<link xlink:href="https://www.FreeBSD.org/copyright/COPYING">GNU General Public License (GPL)</link> 或 <link xlink:href="https://www.FreeBSD.org/copyright/COPYING.LIB">GNU Library General Public License (LGPL)</link>版權宣告,雖然這些版權宣告是用來保障而非限制使用者的權 利,畢竟是不那麼自由了些。由於這些 GPL 的軟體在商業使用上會引起 非常複雜的版權問題,因此只要有機會,我們會盡量以採用比較鬆的 <link xlink:href="https://www.FreeBSD.org/copyright/freebsd-license.html">FreeBSD 版權</link> 的軟體來取代這些 GPL 版權宣告的軟體。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="replace-current-OS">
- <para>FreeBSD 可以取代我現在在用的作業系統嗎?</para>
- </question>
-
- <answer>
- <para>對大部份的人來說是這樣沒錯,但事實上這問題並沒有這麼好回答。</para>
-
- <para>大部份的人並不是真正在使用一個作業系統。他們使用的是應用程式 ;而那些應用程式才是真正用到作業系統的東西。FreeBSD 是設計用來提供一個強韌且功能完整的作業環境給應用程式來執行。它支援了多種瀏覽器,辦公室套件軟體,電子郵件閱讀軟體,繪圖程式,程式設計環境,網路伺服器軟體,以及幾乎所有你想要的東西。大部份的程式都可以靠 <link xlink:href="https://www.FreeBSD.org/ports/">Ports Collection</link> 來管理。</para>
-
- <para>但是如果你想要使用的應用程式只能在某個特定的作業系統上面執行 的話,你就不能輕易地把它換掉,或者指望在 FreeBSD 上有很相似的應用程式才有機會。如果你想要的是一個強健的辦公室或是網路伺服器,或是一部穩定的工作站,FreeBSD 無疑是您的最佳選擇。世界各地有很多使用者,包括初學或資深的 <trademark class="registered">UNIX</trademark> 管理人員都選用 FreeBSD 當他們唯一的桌上作業系統。</para>
-
- <para>如果你是從其他的 <trademark class="registered">UNIX</trademark>-like 環境轉換到 FreeBSD 的話會很熟悉。 <trademark class="registered">Windows</trademark> 或是 <trademark class="registered">Mac OS</trademark> 的使用者可能會對 <link xlink:href="https://www.trueos.org">TrueOS</link> 有興趣,他是基於 FreeBSD 的一個桌面環境發行版,非<trademark class="registered">UNIX</trademark> 使用者可能就要多花一點時間來學習怎麼用 <trademark class="registered">UNIX</trademark> 的 方法來做事。你可以從這份 <acronym>FAQ</acronym> 和 <link xlink:href="@@URL_RELPREFIX@@/doc/zh_TW.UTF-8/books/handbook/index.html">FreeBSD 使用手冊</link> 來入門。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="why-called-FreeBSD">
- <para>為什麼要叫做 FreeBSD?</para>
- </question>
-
- <answer>
- <itemizedlist>
- <listitem>
- <para>您可以免費使用它,即使是用於商業用途。</para>
- </listitem>
-
- <listitem>
- <para>整個 FreeBSD 作業系統完整的原始程式都可以免費取得,而且不管是在使用,散佈或是整合進其他程式等各方面也只受到最小的限制 (不論是否用於商業用途)。</para>
- </listitem>
-
- <listitem>
- <para>任何人都可以自由地把他對系統的改良或錯誤修正的程式碼加入 source tree 之中 (當然要符合幾個先決條件)。</para>
- </listitem>
- </itemizedlist>
-
- <para>特別值得注意的是這裡的 “free” 出現了兩次,而且它們 的意思是不一樣的:一種代表 “免費”,另一種代表 “自由”。您可以拿 FreeBSD 去做任何您想要做的事,除了一些例外,例如您宣稱 FreeBSD 是您寫的。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="differences-to-other-bsds">
- <para>FreeBSD 及 NetBSD, OpenBSD 以及其他 open source BSD 作業系統之間有何不同之處呢?</para>
- </question>
-
- <answer>
- <para>James Howard 寫了一篇關於不同計畫的差異和歷史淵源的好文章叫 <link xlink:href="https://jameshoward.us/archive/the-bsd-family-tree/">The BSD Family Tree</link> 可以回答這個問題。雖然有些資訊有點過時,但是關於歷史淵源的部份仍是相當正確的。</para>
-
- <para>時至今日,大部分的 BSD 家族仍是共用修補和程式碼的。這些 BSD 家族有著共同的祖先。</para>
-
- <para> FreeBSD 的設計目的如 <xref linkend="FreeBSD-goals"/> 所述。其他 BSD 家族的設計目的如下所述:</para>
-
- <itemizedlist>
- <listitem>
- <para>OpenBSD 目標在作業系統的安全性。OpenBSD團隊寫的 <citerefentry><refentrytitle>ssh</refentrytitle><manvolnum>1</manvolnum></citerefentry> 和 <citerefentry><refentrytitle>pf</refentrytitle><manvolnum>4</manvolnum></citerefentry> 都移植到了 FreeBSD。</para>
- </listitem>
-
- <listitem>
- <para>NetBSD 目標在易於移植到其他的硬體平台。</para>
- </listitem>
-
- <listitem>
- <para>DragonFly BSD 是 FreeBSD 4.8 的一個分支,發展出許多有趣的特色,包括 HAMMER 檔案系統和支援 <quote>vkernels</quote> 使用者模式。</para>
- </listitem>
- </itemizedlist>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="latest-version">
- <para>最新版的 FreeBSD 是那一版?</para>
- </question>
-
- <answer>
- <para>在 FreeBSD 開發的任何時間點,都有多個平行的分支。12.<replaceable>X</replaceable> releases 是從 <emphasis>12-STABLE</emphasis> 分支而來,而 11.<replaceable>X</replaceable> releases 是從 <emphasis>11-STABLE</emphasis> 分支而來。</para>
-
- <para>在 9.0 之前,11.<replaceable>X</replaceable> 系列仍屬 <emphasis>-STABLE</emphasis>分支。 然而從13.<replaceable>X</replaceable> 發行開始,11.<replaceable>X</replaceable> 將只著重在重大問題上(比如:漏洞修補、安全維護)以及所謂的 <quote>extended support</quote> 。</para>
-
- <para xml:lang="en">Version <link xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/i386/i386/12.0-RELEASE/">12.0</link>
- is the latest release from the <emphasis>12-STABLE</emphasis> branch; it was
- released in December 2018. Version <link xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/i386/10.4-RELEASE/">10.4</link>
- is the latest release from the <emphasis>11-STABLE</emphasis> branch; it
- was released in October 2017.</para>
-
- <para>Releases 版 <link linkend="release-freq">每幾個月</link> 才會發行一次。 雖然如此,有很多人和 FreeBSD 原始碼同步更新 (詳見 <link linkend="current">FreeBSD-CURRENT</link> 和 <link linkend="stable">FreeBSD-STABLE</link>的相關問題) ,但因為原始碼是一直不斷地在變動的,所以如果要這麼做的話得要花上更多的精力。</para>
-
- <para>其他更多相關 FreeBSD 發行情報,可由 FreeBSD 網站上的 <link xlink:href="https://www.FreeBSD.org/releng/index.html#release-build">Release Engineering 頁面</link> 和 <citerefentry><refentrytitle>release</refentrytitle><manvolnum>7</manvolnum></citerefentry>得知。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="current">
- <para>什麼是 <emphasis>FreeBSD-CURRENT</emphasis>?</para>
- </question>
-
- <answer>
- <para><link xlink:href="@@URL_RELPREFIX@@/doc/zh_TW.UTF-8/books/handbook/current-stable.html#current">FreeBSD-CURRENT</link> 指的是正在發展中的作業系統版本,它終將在適當的時機成為 FreeBSD-STABLE 分支。它實在是只適合給系統發展者以及有毅力的業餘愛好者使用 。如果想要得到有關如何使用<emphasis>-CURRENT</emphasis>的深入資訊,請參考<link xlink:href="@@URL_RELPREFIX@@/doc/zh_TW.UTF-8/books/handbook/index.html">使用手冊</link>的<link xlink:href="@@URL_RELPREFIX@@/doc/zh_TW.UTF-8/books/handbook/current-stable.html#current">相關部份</link>。</para>
-
- <para>如果您對 FreeBSD 本身並不是很熟悉那麼您就不應該使用FreeBSD-CURRENT。 這個分支的程式碼有時候變動得很快,而且可能會因此 而使您有好幾天的時間無法更新您的系統。我們假設使用 FreeBSD-CURRENT 的使用者都有能力去分析他們所遇到的問題,除錯,並且回報問題。</para>
-
- <para>我們每天都會根據目前 <emphasis>-CURRENT</emphasis> 和 <emphasis>-STABLE</emphasis> 的狀況對這兩個分支各發行一個 <link xlink:href="@@URL_RELPREFIX@@/snapshots/">snapshot</link> 版。發表這些 snapshot 的目的在於:</para>
-
- <itemizedlist>
- <listitem>
- <para>測試最新版的安裝程式。</para>
- </listitem>
-
- <listitem>
- <para>提供一個簡單的方法給那些喜歡使用 <emphasis>-CURRENT</emphasis> 或是 <emphasis>-STABLE</emphasis> 但是沒有時間和頻寬去每天昇級的使用者。</para>
- </listitem>
-
- <listitem>
- <para>為了替我們發展中的程式保留一個固定的參考點,以防止我們未來不幸搞砸了。(雖然一般而言 Subversion 可以防止類似這種的可怕事件)</para>
- </listitem>
-
- <listitem>
- <para>為了確保所有需要測試的新功能或修正都可以得到最多的測試。</para>
- </listitem>
- </itemizedlist>
-
- <para>我們不對 <emphasis>-CURRENT</emphasis> snapshot 做任何目的的 <quote>品質保證</quote> 。如果你想要的是一個穩定且經過充分測試過的系統的話, 最好選擇使用完整 releases.</para>
-
- <para>您可以直接從 <link xlink:href="@@URL_RELPREFIX@@/snapshots/">snapshot</link> 取得 -CURRENT 的 snapshot release。</para>
-
- <para>對每個有在活動的分支而言,都會定期產生一次 snapshots。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="stable">
- <para>什麼是 <emphasis>FreeBSD-STABLE</emphasis> ?</para>
- </question>
-
- <answer>
- <para>回溯到 FreeBSD 2.0.5 剛發表的時候,我們決定把 FreeBSD 的發展 分成兩支。一支叫做 <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/current-stable.html#stable">-STABLE</link>,另一支叫 <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/current-stable.html#current">-CURRENT</link>。主要發行版是由<emphasis>FreeBSD-STABLE</emphasis> 這個開發分支而來。他的變動較慢,而且一般來說假設他們都已經先在FreeBSD-CURRENT測試過了。然而在任何時候,FreeBSD-STABLE的原始碼仍有可能不一定適合一般用途,因為他可能包含在 FreeBSD-CURRENT 沒有發現到的錯誤。沒有能力和資源的使用者應該改使用 FreeBSD 正式發行版。<emphasis>FreeBSD-CURRENT</emphasis> 從2.0開始就是另一個分支,一直到12.0-RELEASE和之後的版本都還是。更多關於開發分支的資訊請見 <quote><link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/articles/releng/release-proc.html#rel-branch">FreeBSD Release Engineering: Creating the Release Branch</link></quote> ,分支的開發狀態和接下來的發行計畫時間表可以在 <link xlink:href="https://www.FreeBSD.org/releng">Release Engineering 資訊</link> 找到。</para>
-
- <para>12.0-STABLE 是目前正在發展中的 <emphasis>-STABLE</emphasis> 分支。最新的 12.0-STABLE 是在 2018年12月發行的 12.0-RELEASE。</para>
-
- <para><emphasis>12-CURRENT</emphasis> 這個分支是 FreeBSD 的 <emphasis>-CURRENT</emphasis> 分支,仍然不斷地在發展當中。 如果想要知道更多關於這個分支的資訊的話,請參考 <link linkend="current">什麼是 FreeBSD-CURRENT?</link> 。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="release-freq">
- <para>每次新的 FreeBSD 將於什麼時候推出?</para>
- </question>
-
- <answer>
- <para>一般而言,Release Engineering Team <email>re@FreeBSD.org</email> 約每18個月發行一次主要發行版本,約平均每8個月發行一次次要發行版本。每次新版本的發表時程都會事先公告, 相關的開發人員就會知道,什麼時候該先把手邊的計劃完成並且測試過, 此外,這些更動都已經完整地測試過,確保新功能不會影響系統的穩定度。 雖然,等這些好東西進入<emphasis>-STABLE</emphasis> 的時間令人等得有些不耐煩, 但是大多數的使用者都認為這種謹慎的態度是 FreeBSD 最好的優點之一。</para>
-
- <para>有關發行情報的更多細節部分(包括 release 的行程表、進度),都可在 FreeBSD 網站上的 <link xlink:href="https://www.FreeBSD.org/releng/index.html">發行情報</link> 上面獲得。</para>
-
- <para>為了滿足那些需要 (或想要) 新鮮刺激感的使用者, 上面已經提到我們每周都會發行 snapshots 版可供使用。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="responsible">
- <para>誰負責 FreeBSD 的發展?</para>
- </question>
-
- <answer>
- <para>如果是一些有關 FreeBSD 計畫的關鍵性決定,像是整個計畫的走向 或是決定誰可以改 source tree 裡的程式碼這類的事,是由一個由 9 個 人所組成的 <link xlink:href="@@URL_RELPREFIX@@/administration.html#t-core">core team</link> 來決定。而有另一群超過 350 個人的 <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/articles/contributors/article.html#staff-committers">committers</link> 有權利可以直接修改 FreeBSD 的 source tree。</para>
-
- <para>無論如何,大多數的改變都會事前在 <link linkend="mailing">郵件論壇</link>先討論過,而且不分角色,每個人都可以參與討論。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="where-get">
- <para>我要如何取得 FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Every significant release of FreeBSD is available via
- anonymous FTP from the <link xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/">FreeBSD
- FTP site</link>:</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en">The latest <emphasis>12-STABLE</emphasis> release,
- 12.0-RELEASE can be found in the <link xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/i386/i386/12.0-RELEASE/">12.0-RELEASE
- directory</link>.</para>
- </listitem>
-
- <listitem>
- <para><link linkend="current">-CURRENT</link> 和 <link linkend="stable">-STABLE</link> 分支的<link xlink:href="@@URL_RELPREFIX@@/snapshots/">Snapshot</link>版本通常每個月會做一次, 主要是為了提供給那些熱心的測試者和開發人員。</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">The latest <emphasis>11-STABLE</emphasis> release,
- 10.4-RELEASE can be found in the <link xlink:href="ftp://ftp.FreeBSD.org/pub/FreeBSD/releases/i386/10.4-RELEASE/">10.4-RELEASE
- directory</link>.</para>
- </listitem>
- </itemizedlist>
-
- <para>FreeBSD 的 CD、DVD,還有其他取得方式可以在 <link xlink:href="@@URL_RELPREFIX@@/doc/zh_TW.UTF-8/books/handbook/mirrors.html">the Handbook</link> 中找到解答。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="access-pr">
- <para>我要如何去查詢、提交問題回報(Problem Report,簡稱PR)資料庫呢?</para>
- </question>
-
- <answer>
- <para>所有使用者的變更要求都可以經由網頁版的 PR <link xlink:href="https://bugs.FreeBSD.org/search/">查詢</link> 界面來察看。</para>
-
- <para>可以使用瀏覽器經由<link xlink:href="@@URL_RELPREFIX@@/support/bugreports.html">網頁版的 PR 界面</link> 來傳送問題回報</para>
-
- <para>然而,在您回報問題之前,請先閱讀 <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/articles/problem-reports/article.html">如何撰寫 FreeBSD 的問題回報單</link>,這是一篇告訴你怎樣才能寫出一篇真正有用的問題回報單。</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="support">
- <title>文件與技術支援</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="books">
- <para>有哪些 FreeBSD 相關的好書呢?</para>
- </question>
-
- <answer>
- <para>FreeBSD 文件計畫已陸續發表了相當廣泛範圍的文件,可在 <uri xlink:href="https://www.FreeBSD.org/docs.html">https://www.FreeBSD.org/docs.html</uri> 取得。除此之外,也可以參閱使用手冊的 <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/bibliography.html">參考書目</link>建議的其他書籍。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="doc-formats">
- <para>這些文件有其他格式的嗎?像是:純文字(ASCII)或 <trademark class="registered">PostScript</trademark> 之類的格式?</para>
- </question>
-
- <answer>
- <para>有的。這些文件都分別以不同格式儲存以及壓縮處理並放在 FTP 上面,可以從各個 FreeBSD FTP 站的 <link xlink:href="https://download.freebsd.org/ftp/doc/">/pub/FreeBSD/doc/</link> 目錄內找到你要的。</para>
-
- <para>文件以幾種不同的方式分類。包括:</para>
-
- <itemizedlist>
- <listitem>
- <para>文件名稱,例如:<literal>faq</literal> (常見問答集)或是 <literal>handbook</literal> (FreeBSD 使用手冊)等等。</para>
- </listitem>
-
- <listitem>
- <para>文件的語言與編碼。他們是基於 FreeBSD 系統中 <filename>/usr/share/locale</filename> 裡所見到的語系名稱。目前包含的語言與編碼如下:</para>
-
- <informaltable frame="none" pgwide="1">
- <tgroup cols="2">
- <thead>
- <row>
- <entry>語系名稱</entry>
-
- <entry>說明</entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry><literal>en_US.ISO8859-1</literal></entry>
-
- <entry>英文 (美國)</entry>
- </row>
-
- <row>
- <entry><literal>bn_BD.ISO10646-1</literal></entry>
-
- <entry>孟加拉文 (孟加拉)</entry>
- </row>
-
- <row>
- <entry><literal>da_DK.ISO8859-1</literal></entry>
-
- <entry>丹麥文 (丹麥)</entry>
- </row>
-
- <row>
- <entry><literal>de_DE.ISO8859-1</literal></entry>
-
- <entry>德文 (德國)</entry>
- </row>
-
- <row>
- <entry><literal>el_GR.ISO8859-7</literal></entry>
-
- <entry>希臘文 (希臘)</entry>
- </row>
-
- <row>
- <entry><literal>es_ES.ISO8859-1</literal></entry>
-
- <entry>西班牙文 (西班牙)</entry>
- </row>
-
- <row>
- <entry><literal>fr_FR.ISO8859-1</literal></entry>
-
- <entry>法文 (法國)</entry>
- </row>
-
- <row>
- <entry><literal>hu_HU.ISO8859-2</literal></entry>
-
- <entry>匈牙利文 (匈牙利)</entry>
- </row>
-
- <row>
- <entry><literal>it_IT.ISO8859-15</literal></entry>
-
- <entry>義大利文 (義大利)</entry>
- </row>
-
- <row>
- <entry><literal>ja_JP.eucJP</literal></entry>
-
- <entry>日文 (日本, EUC 編碼)</entry>
- </row>
-
- <row>
- <entry><literal>ko_KR.UTF-8</literal></entry>
-
- <entry>韓文 (韓國, UTF-8 編碼)</entry>
- </row>
-
- <row>
- <entry><literal>mn_MN.UTF-8</literal></entry>
-
- <entry>蒙古文 (蒙古, UTF-8 編碼)</entry>
- </row>
-
- <row>
- <entry><literal>nl_NL.ISO8859-1</literal></entry>
-
- <entry>荷蘭文 (荷蘭)</entry>
- </row>
-
- <row>
- <entry><literal>pl_PL.ISO8859-2</literal></entry>
-
- <entry>波蘭文 (波蘭)</entry>
- </row>
-
- <row>
- <entry><literal>pt_BR.ISO8859-1</literal></entry>
-
- <entry>葡萄牙文 (巴西)</entry>
- </row>
-
- <row>
- <entry><literal>ru_RU.KOI8-R</literal></entry>
-
- <entry>俄文 (俄羅斯, KOI8-R 編碼)</entry>
- </row>
-
- <row>
- <entry><literal>tr_TR.ISO8859-9</literal></entry>
-
- <entry>土耳其文 (土耳其)</entry>
- </row>
-
- <row>
- <entry><literal>zh_CN.UTF-8</literal></entry>
-
- <entry>簡體中文 (中國, UTF-8 編碼)</entry>
- </row>
-
- <row>
- <entry><literal>zh_TW.UTF-8</literal></entry>
-
- <entry>正體中文 (台灣, UTF-8 編碼)</entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
-
- <note>
- <para>上列的各國翻譯語系文件中,並非所有文件都有翻譯。</para>
- </note>
- </listitem>
-
- <listitem>
- <para>文件的格式。我們的每份文件都提供許多不同的格式,每種格式各有利弊, 有些格式適合線上閱讀,有些則適合列印出美觀的文件。 這些不同格式的文件能夠確保我們的讀者們,無論是在螢幕上閱讀或是列印成紙本,都能夠閱讀他們感興趣的內容,目前有提供的格式如下:</para>
-
- <informaltable frame="none" pgwide="1">
- <tgroup cols="2">
- <thead>
- <row>
- <entry>格式</entry>
-
- <entry>說明</entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry><literal>html-split</literal></entry>
-
- <entry>依章節區分成多個小的、互相連結的 HTML 檔案</entry>
- </row>
-
- <row>
- <entry><literal>html</literal></entry>
-
- <entry>所有內容包含在單一個 HTML 檔案</entry>
- </row>
-
- <row>
- <entry><literal>pdf</literal></entry>
-
- <entry> Adobe's PDF 格式</entry>
- </row>
-
- <row>
- <entry><literal>ps</literal></entry>
-
- <entry><trademark class="registered">PostScript</trademark></entry>
- </row>
-
- <row>
- <entry><literal>rtf</literal></entry>
-
- <entry><trademark class="registered">Microsoft</trademark> 的 RTF 格式</entry>
- </row>
-
- <row>
- <entry><literal>txt</literal></entry>
-
- <entry>純文字</entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
-
- <note>
- <para>當用 Word 讀取 RTF 格式時,頁碼並不會被自動更新。在開啟檔案後按下<keycombo action="simul"><keycap>Ctrl</keycap><keycap>A</keycap></keycombo>, <keycombo action="simul"><keycap>Ctrl</keycap><keycap>End</keycap></keycombo>, <keycap>F9</keycap> 來更新頁碼。</para>
- </note>
- </listitem>
-
- <listitem>
- <para>壓縮和打包方式</para>
-
- <orderedlist>
- <listitem>
- <para>當採用 <literal>html-split</literal> 格式時,檔案先透過 <citerefentry><refentrytitle>tar</refentrytitle><manvolnum>1</manvolnum></citerefentry> 工具來進行打包。接著再將產生出來的 <filename>.tar</filename> 檔接透過第二點所述的壓縮方式壓縮。</para>
- </listitem>
-
- <listitem>
- <para>其他的格式都是單一個檔案。例如 <filename>article.pdf</filename>、<filename>book.html</filename> ,以此類推。</para>
-
- <para>這些檔案接著透過 <literal>zip</literal> 或 <literal>bz2</literal> 來壓縮。 <citerefentry><refentrytitle>tar</refentrytitle><manvolnum>1</manvolnum></citerefentry> 工具可用來解壓縮這些檔案。</para>
-
- <para>因此 <trademark class="registered">PostScript</trademark> 版本的手冊經過 <literal>bzip2</literal> 壓縮後會存成一個叫做 <filename>book.ps.bz2</filename> 的檔案,並位於 <filename>handbook/</filename> 資料夾。</para>
- </listitem>
- </orderedlist>
- </listitem>
- </itemizedlist>
-
- <para>在選取格式與壓縮方式後,下載壓縮後的檔案並解壓縮,再把文件複製到想要的地方。</para>
-
- <para>舉例來說,透過 <citerefentry><refentrytitle>bzip2</refentrytitle><manvolnum>1</manvolnum></citerefentry> 壓縮的英文問與答的章節分割 HTML 版本,可以在 <filename>doc/en_US.ISO8859-1/books/faq/book.html-split.tar.bz2</filename> 中找到。若要下載並解壓縮這個檔案,請輸入</para>
-
- <screen><prompt>#</prompt> <userinput>fetch https://download.freebsd.org/ftp/doc/en_US.ISO8859-1/books/faq/book.html-split.tar.bz2</userinput>
-<prompt>#</prompt> <userinput>tar xvf book.html-split.tar.bz2</userinput></screen>
-
- <para>如果檔案被壓縮過的話,<application>tar</application> 會自動偵測正確的格式並解壓縮出一堆 <filename>.html</filename> 檔案。主要的檔案是 <filename>index.html</filename>,包含了主目錄跟介紹以及連接到文件其他部份的連結。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="mailing">
- <para>哪裡有關於 FreeBSD 的郵遞論壇(mailing lists)呢? 有哪些可以使用的 FreeBSD 新聞群組(news groups)呢?</para>
- </question>
-
- <answer>
- <para>請參考FreeBSD 使用手冊上的 <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/eresources.html#eresources-mail"> 郵件論壇 (mailing-lists)</link> 。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="irc">
- <para>有 FreeBSD IRC (Internet Relay Chat)頻道嗎?</para>
- </question>
-
- <answer>
- <para>有的,大部分的 IRC 主機都有 FreeBSD 聊天頻道:</para>
-
- <itemizedlist>
- <listitem>
- <para><link xlink:href="http://www.efnet.org/index.php">EFNet</link> 上的 <literal>#FreeBSDhelp</literal> 頻道專門用來幫助 FreeBSD 使用著</para>
- </listitem>
-
- <listitem>
- <para><link xlink:href="http://freenode.net/">Freenode</link> 上的 <literal>#FreeBSD</literal> 頻道是一個有許多使用者的一般求助頻道。這個頻道時常聊一些題外話,但主要還是讓使用者問 FreeBSD 相關問題的地方。其他使用者可以協助解答一些基本的問題,並請盡量提供使用手冊的參考或是提供連結來提供更深入的資訊。雖然這個頻道有來自世界各地的使用者,但這是一個英文為主的頻道。非母語人士應該以英文提問,並在必要的時候移駕到 <literal>##freebsd-lang</literal> 頻道。</para>
- </listitem>
-
- <listitem>
- <para><link xlink:href="http://www.dal.net/">DALNET</link> 的<literal>#FreeBSD</literal> 頻道,可由 <systemitem>irc.dal.net</systemitem> (位於美國)及<systemitem>irc.eu.dal.net</systemitem> (位於歐洲)進入。</para>
- </listitem>
-
- <listitem>
- <para><link xlink:href="http://www.undernet.org/">UNDERNET</link> 上的 <literal>#FreeBSD</literal> 頻道可由 <systemitem>us.undernet.org</systemitem>(位於美國)及 <systemitem>eu.undernet.org</systemitem> (位於歐洲)進入。由於這是個輔助新手用的頻道, 請記得閱讀別人向你提及的連結或檔案。</para>
- </listitem>
-
- <listitem>
- <para><link xlink:href="http://www.rusnet.org.ru/">RUSNET</link> 上的 <literal>#FreeBSD</literal> 頻道是俄語國家的 FreeBSD 使用者頻道。 這裡同時也是一般交流的討論好去處。</para>
- </listitem>
-
- <listitem>
- <para><link xlink:href="http://freenode.net/">Freenode</link> 上的 <literal>#bsdchat</literal> 頻道是一個正體中文(UTF-8 編碼)頻道專門用來幫助 FreeBSD 使用著。這裡也歡迎一般非技術的交流討論。</para>
- </listitem>
- </itemizedlist>
-
- <para xml:lang="en">The FreeBSD wiki has a <link xlink:href="https://wiki.freebsd.org/IRC/Channels">good
- list</link> of IRC channels.</para>
-
- <para>每個頻道都是不同且互相獨立的。因為他們的聊天風格不同,您可以每個都試試看來找到適合您的頻道。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="forums">
- <para>有沒有任何網頁形式的 FreeBSD 論壇呢?</para>
- </question>
- <answer>
- <para>官方的 FreeBSD 論壇位於 <link xlink:href="https://forums.FreeBSD.org/">https://forums.FreeBSD.org/</link>。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="training">
- <para>可以從哪邊獲得商業化的 FreeBSD 的教育課程及技術支援呢?</para>
- </question>
-
- <answer>
- <para><link xlink:href="http://www.ixsystems.com">iXsystems, Inc.</link>, <link xlink:href="http://www.freebsdmall.com/">FreeBSD 商城</link>的母公司,提供 FreeBSD 開發與調校解決方案與 FreeBSD 與 TrueOS 的軟體 <link xlink:href="http://www.ixsystems.com/support">支援</link>。</para>
-
- <para>BSD Certification Group, Inc. 提供 DragonFly BSD、FreeBSD、NetBSD 與 OpenBSD 的系統管理認證。請參閱 <link xlink:href="http://www.BSDCertification.org">他們的網站</link> 來獲得更多資訊。</para>
-
- <para>如果有其他組織提供技術訓練或技術支援,請聯絡 FreeBSD 計畫來加入以上清單。</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="install">
- <info>
- <title>安裝</title>
-
- <author xml:lang="en">
- <personname>
- <firstname>Nik</firstname>
- <surname>Clayton</surname>
- </personname>
- <affiliation>
- <address xml:lang="en">
- <email>nik@FreeBSD.org</email>
- </address>
- </affiliation>
- </author>
- </info>
-
- <qandaset>
-
- <qandaentry>
- <question xml:id="which-architecture">
- <para xml:lang="en">Which platform should I download? I have a 64
- bit capable <trademark class="registered">Intel</trademark> CPU,
- but I only see <literal>amd64</literal>.</para>
- </question>
-
- <answer>
- <para xml:lang="en">amd64 is the term FreeBSD uses for 64-bit
- compatible x86 architectures (also known as "x86-64" or
- "x64"). Most modern computers should use amd64.
- Older hardware should use i386. When installing
- on a non-x86-compatible architecture, select the
- platform which best matches the hardware.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="floppy-download">
- <para xml:lang="en">Which file do I download to get FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">On the <link xlink:href="https://www.freebsd.org/where.html">Getting
- FreeBSD</link> page, select <literal>[iso]</literal> next
- to the architecture that matches the hardware.</para>
-
- <para xml:lang="en">Any of the following can be used:</para>
-
- <informaltable frame="none" pgwide="1">
- <tgroup cols="2">
- <thead>
- <row>
- <entry>檔案</entry>
- <entry>描述</entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry><filename>disc1.iso</filename></entry>
- <entry xml:lang="en">Contains enough to install FreeBSD and
- a minimal set of packages.</entry>
- </row>
-
- <row>
- <entry><filename>dvd1.iso</filename></entry>
- <entry xml:lang="en">Similar to <filename>disc1.iso</filename>
- but with additional packages.</entry>
- </row>
-
- <row>
- <entry><filename>memstick.img</filename></entry>
- <entry xml:lang="en">A bootable image sufficient for writing to a
- USB stick.</entry>
- </row>
-
- <row>
- <entry><filename>bootonly.iso</filename></entry>
- <entry xml:lang="en">A minimal image that requires network access
- during installation to completely install
- FreeBSD.</entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
-
- <para xml:lang="en">Full instructions on this procedure and a little bit
- more about installation issues in general can be found in
- the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/bsdinstall.html">Handbook
- entry on installing FreeBSD</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="floppy-image-too-large">
- <para xml:lang="en">What do I do if the install image does not
- boot?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This can be caused by not downloading the image in
- <emphasis>binary</emphasis> mode when using
- <acronym>FTP</acronym>.</para>
-
- <para xml:lang="en">Some FTP clients default their transfer mode to
- <emphasis>ascii</emphasis> and attempt to change any
- end-of-line characters received to match the
- conventions used by the client's system. This will
- almost invariably corrupt the boot image. Check the
- SHA-256 checksum of the downloaded boot image: if it
- is not <emphasis>exactly</emphasis> that on the
- server, then the download process is suspect.</para>
-
- <para xml:lang="en">When using a command line FTP client, type
- <emphasis>binary</emphasis> at the FTP command prompt
- after getting connected to the server and before
- starting the download of the image.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="install-instructions-location">
- <para>可以在哪邊找到安裝 FreeBSD 的解說步驟呢?</para>
- </question>
-
- <answer>
- <para>安裝說明可以在 <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/bsdinstall.html">使用手冊的安裝 FreeBSD</link> 找到。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="need-to-run">
- <para>要跑 FreeBSD 至少需要什麼樣的配備呢?</para>
- </question>
-
- <answer>
- <para>FreeBSD 需要 486 以上的 PC,64 MB 以上的 RAM,和至少 1.1 GB 的硬碟空間。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="custom-boot-floppy">
- <para>要怎樣才能自行打造專用的安裝磁片呢?</para>
- </question>
-
- <answer>
- <para>可以透過編譯客製化發行版本來建立客製化的 FreeBSD 安裝媒體。請參閱 <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/articles/releng/article.html">Release Engineering</link> 文章的說明。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="windows-coexist">
- <para><trademark class="registered">Windows</trademark> 可以與 FreeBSD 共存嗎?</para>
- </question>
-
- <answer>
- <para>如果 <trademark class="registered">Windows</trademark> 先安裝,那就可以。 FreeBSD 的開機管理程式將會管理 <trademark class="registered">Windows</trademark> 和 FreeBSD 的開機啟動。 如果 <trademark class="registered">Windows</trademark> 後安裝,它將覆蓋開機管理程式。如果發生這種情況,請見下一小節。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="bootmanager-restore">
- <para xml:lang="en">Another operating system destroyed my Boot Manager.
- How do I get it back?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This depends upon the boot manager.
- The FreeBSD boot selection menu can be reinstalled using
- <citerefentry><refentrytitle>boot0cfg</refentrytitle><manvolnum>8</manvolnum></citerefentry>. For example, to restore the boot menu
- onto the disk <replaceable>ada0</replaceable>:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>boot0cfg -B ada0</userinput></screen>
-
- <para xml:lang="en">The non-interactive MBR bootloader can be installed
- using <citerefentry><refentrytitle>gpart</refentrytitle><manvolnum>8</manvolnum></citerefentry>:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>gpart bootcode -b /boot/mbr ada0</userinput></screen>
-
- <para xml:lang="en">For more complex situations, including GPT disks, see
- <citerefentry><refentrytitle>gpart</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="need-complete-sources">
- <para>我需要安裝完整的原始碼嗎?</para>
- </question>
-
- <answer>
- <para xml:lang="en">In general, no. There is nothing in the base system
- which requires the presence of the source to operate.
- Some ports, like <package>sysutils/lsof</package>, will
- not build unless the source is installed. In particular,
- if the port builds a kernel module or directly operates on
- kernel structures, the source must be installed.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="need-kernel">
- <para>需要重新 build kernel 嗎?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Usually not. The supplied <literal>GENERIC</literal>
- kernel contains the drivers an ordinary computer will
- need. <citerefentry><refentrytitle>freebsd-update</refentrytitle><manvolnum>8</manvolnum></citerefentry>, the FreeBSD binary upgrade
- tool, cannot upgrade custom kernels, another reason to
- stick with the <literal>GENERIC</literal> kernel when
- possible. For computers with very limited RAM, such as
- embedded systems, it may be worthwhile to build a smaller
- custom kernel containing just the required drivers.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="password-encryption">
- <para xml:lang="en">Should I use DES, Blowfish, or MD5 passwords and how
- do I specify which form my users receive?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FreeBSD uses
- <emphasis>SHA512</emphasis> by
- default. DES
- passwords are still available for backwards compatibility
- with operating systems that still
- use the less secure password format. FreeBSD also supports
- the Blowfish and MD5 password formats. Which
- password format to use for new passwords is controlled by
- the <literal>passwd_format</literal> login capability in
- <filename>/etc/login.conf</filename>, which takes values
- of <literal>des</literal>, <literal>blf</literal> (if
- these are available) or <literal>md5</literal>. See the
- <citerefentry><refentrytitle>login.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> manual page for more information about
- login capabilities.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ffs-limits">
- <para xml:lang="en">What are the limits for FFS file systems?</para>
- </question>
-
- <answer>
- <para xml:lang="en">For FFS file systems, the largest file system is
- practically limited by the amount of memory required to
- <citerefentry><refentrytitle>fsck</refentrytitle><manvolnum>8</manvolnum></citerefentry> the file system. <citerefentry><refentrytitle>fsck</refentrytitle><manvolnum>8</manvolnum></citerefentry> requires one
- bit per fragment, which with the default fragment size of
- 4 KB equates to 32 MB of memory per TB of disk.
- This does mean that on architectures which limit userland
- processes to 2 GB (e.g., <trademark>i386</trademark>), the maximum
- <citerefentry><refentrytitle>fsck</refentrytitle><manvolnum>8</manvolnum></citerefentry>'able filesystem is ~60 TB.</para>
-
- <para xml:lang="en">If there was not a <citerefentry><refentrytitle>fsck</refentrytitle><manvolnum>8</manvolnum></citerefentry> memory limit the
- maximum filesystem size would be 2 ^ 64 (blocks)
- * 32 KB =&gt; 16 Exa * 32 KB =&gt; 512
- ZettaBytes.</para>
-
- <para xml:lang="en">The maximum size of a single FFS file is approximately
- 2 PB with the default block size of 32 KB. Each
- 32 KB block can point to 4096 blocks. With triple
- indirect blocks, the calculation is 32 KB * 12 +
- 32 KB * 4096 + 32 KB * 4096^2 + 32 KB *
- 4096^3. Increasing the block size to 64 KB will
- increase the max file size by a factor of 16.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="archsw-readin-failed-error">
- <para xml:lang="en">Why do I get an error message, <errorname>readin
- failed</errorname> after compiling and booting a new
- kernel?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The world and kernel are out of sync. This
- is not supported. Be sure to use <command>make
- buildworld</command> and <command>make
- buildkernel</command> to update the kernel.</para>
-
- <para xml:lang="en">Boot the system by specifying the kernel directly at
- the second stage, pressing any key when the
- <literal>|</literal> shows up before loader is
- started.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="general-configuration-tool">
- <para>是否有工具可以執行安裝後的設定工作嗎?</para>
- </question>
-
- <answer>
- <para>是的。<application>bsdconfig</application> 提供很棒的介面來進行 FreeBSD 安裝後設定。</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="hardware">
- <title>硬體相容性</title>
-
- <sect1 xml:id="compatibility-general">
- <title>一般問題</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="which-hardware-to-get">
- <para xml:lang="en">I want to get a piece of hardware for my FreeBSD
- system. Which model/brand/type is best?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This is discussed continually on the FreeBSD mailing
- lists but is to be expected since hardware changes so
- quickly. Read through the Hardware Notes
- for FreeBSD <link xlink:href="https://www.FreeBSD.org/releases/12.0R/hardware.html">12.0</link>
- or <link xlink:href="https://www.FreeBSD.org/releases/10.4R/hardware.html">10.4</link>
- and search the mailing list <link xlink:href="https://www.FreeBSD.org/search/#mailinglists">archives</link>
- before asking about the latest and greatest hardware.
- Chances are a discussion about that type of hardware
- took place just last week.</para>
-
- <para xml:lang="en">Before purchasing a laptop, check the archives for
- <link xlink:href="http://lists.FreeBSD.org/mailman/listinfo/freebsd-mobile">FreeBSD laptop computer mailing list</link> and <link xlink:href="http://lists.FreeBSD.org/mailman/listinfo/freebsd-questions">FreeBSD general questions mailing list</link>, or possibly a specific
- mailing list for a particular hardware type.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="memory-upper-limitation">
- <para xml:lang="en">What are the limits for memory? Does FreeBSD support
- more than 4 GB of memory
- (RAM)? More than 16 GB? More than
- 48 GB?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FreeBSD as an operating system generally supports
- as much physical memory (RAM) as the platform it is
- running on does. Keep in mind that different platforms
- have different limits for memory; for example <trademark>i386</trademark>
- without <acronym>PAE</acronym> supports at most
- 4 GB of memory (and usually less than that because
- of PCI address space) and <trademark>i386</trademark> with PAE supports at
- most 64 GB memory. As of FreeBSD 10, AMD64
- platforms support up to 4 TB of physical
- memory.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="memory-i386-over-4gb">
- <para xml:lang="en">Why does FreeBSD report less than 4 GB memory when
- installed on an <trademark>i386</trademark> machine?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The total address space on <trademark>i386</trademark> machines is
- 32-bit, meaning that at most 4 GB of memory is
- addressable (can be accessed). Furthermore, some
- addresses in this range are reserved by hardware for
- different purposes, for example for using and
- controlling PCI devices, for accessing video memory, and
- so on. Therefore, the total amount of memory usable by
- the operating system for its kernel and applications is
- limited to significantly less than 4 GB. Usually,
- 3.2 GB to 3.7 GB is the maximum usable
- physical memory in this configuration.</para>
-
- <para xml:lang="en">To access more than 3.2 GB to 3.7 GB of
- installed memory (meaning up to 4 GB but also more
- than 4 GB), a special tweak called
- <acronym>PAE</acronym> must be used. PAE stands for
- Physical Address Extension and is a way for 32-bit x86
- CPUs to address more than 4 GB of memory. It
- remaps the memory that would otherwise be overlaid by
- address reservations for hardware devices above the
- 4 GB range and uses it as additional physical
- memory (see <citerefentry><refentrytitle>pae</refentrytitle><manvolnum>4</manvolnum></citerefentry>). Using PAE has some drawbacks;
- this mode of memory access is a little bit slower than
- the normal (without PAE) mode and loadable modules (see
- <citerefentry><refentrytitle>kld</refentrytitle><manvolnum>4</manvolnum></citerefentry>) are not supported. This means all drivers
- must be compiled into the kernel.</para>
-
- <para xml:lang="en">The most common way to enable PAE is to build a new
- kernel with the special ready-provided kernel
- configuration file called <filename>PAE</filename>,
- which is already configured to build a safe kernel.
- Note that some entries in this kernel configuration file
- are too conservative and some drivers marked as unready
- to be used with PAE are actually usable. A rule of
- thumb is that if the driver is usable on 64-bit
- architectures (like AMD64), it is also usable with PAE.
- When creating a custom kernel configuration
- file, PAE can be enabled by adding the following
- line:</para>
-
- <programlisting xml:lang="en">options PAE</programlisting>
-
- <para xml:lang="en">PAE is not much used nowadays because most new x86
- hardware also supports running in 64-bit mode, known as
- AMD64 or <trademark class="registered">Intel</trademark> 64. It has a much larger address
- space and does not need such tweaks. FreeBSD supports
- AMD64 and it is recommended that this version of FreeBSD be
- used instead of the <trademark>i386</trademark> version if 4 GB or more
- memory is required.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </sect1>
-
- <sect1 xml:id="compatibility-processors">
- <title xml:lang="en">Architectures and Processors</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="architectures">
- <para xml:lang="en">Does FreeBSD support architectures other than the
- x86?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes. FreeBSD divides support into multiple tiers.
- Tier 1 architectures, such as i386 or amd64; are fully
- supported. Tiers 2 and 3 are supported on a
- best-effort basis. A full explanation of the tier
- system is available in the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/articles/committers-guide/archs.html">Committer's
- Guide.</link></para>
-
- <para xml:lang="en">A complete list of supported architectures can be
- found on the <link xlink:href="https://www.FreeBSD.org/platforms/">platforms
- page.</link></para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="smp-support">
- <para xml:lang="en">Does FreeBSD support Symmetric Multiprocessing
- (SMP)?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FreeBSD supports symmetric multi-processor (SMP) on all
- non-embedded platforms (e.g, i386, amd64,
- etc.). SMP is also supported in arm and MIPS kernels,
- although some CPUs may not support this. FreeBSD's SMP
- implementation uses fine-grained locking, and
- performance scales nearly linearly with number of
- CPUs.</para>
-
- <para xml:lang="en"><citerefentry><refentrytitle>smp</refentrytitle><manvolnum>4</manvolnum></citerefentry> has more details.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="microcode">
- <para xml:lang="en">What is microcode?
- How do I install <trademark class="registered">Intel</trademark> CPU microcode updates?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Microcode is a method of programmatically
- implementing hardware level instructions. This allows
- for CPU bugs to be fixed without replacing the on board
- chip.</para>
-
- <para xml:lang="en">Install <package>sysutils/devcpu-data</package>,
- then add:</para>
-
- <programlisting xml:lang="en">microcode_update_enable="YES"</programlisting>
-
- <para xml:lang="en">to <filename>/etc/rc.conf</filename></para>
- </answer>
- </qandaentry>
- </qandaset>
- </sect1>
-
- <sect1 xml:id="compatibility-drives">
- <title xml:lang="en">Hard Drives, Tape Drives, and CD and DVD Drives</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="supported-hard-drives">
- <para xml:lang="en">What kind of hard drives does FreeBSD support?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FreeBSD supports EIDE, SATA, SCSI, and SAS drives (with
- a compatible controller; see the next section), and all
- drives using the original <quote>Western Digital</quote>
- interface (MFM, RLL, ESDI, and of course IDE). A few
- ESDI controllers that use proprietary interfaces may not
- work: stick to WD1002/3/6/7 interfaces and
- clones.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="supported-scsi-controllers">
- <para xml:lang="en">Which SCSI or SAS controllers are supported?</para>
- </question>
-
- <answer>
- <para xml:lang="en">See the complete list in the Hardware Notes for FreeBSD
- <link xlink:href="https://www.FreeBSD.org/releases/12.0R/hardware.html">12.0</link>
- or <link xlink:href="https://www.FreeBSD.org/releases/10.4R/hardware.html">10.4</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="tape-support">
- <para xml:lang="en">What types of tape drives are supported?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FreeBSD supports all standard SCSI tape
- interfaces.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="tape-changer-support">
- <para xml:lang="en">Does FreeBSD support tape changers?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FreeBSD supports SCSI changers using the <citerefentry><refentrytitle>ch</refentrytitle><manvolnum>4</manvolnum></citerefentry>
- device and the <citerefentry><refentrytitle>chio</refentrytitle><manvolnum>1</manvolnum></citerefentry> command. The details of how
- to control the changer can be found in
- <citerefentry><refentrytitle>chio</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
-
- <para xml:lang="en">While
- <application>AMANDA</application> and some other
- products already understands changers, other
- applications only know how to move a tape from one point
- to another. In this case, keep track of which slot a
- tape is in and which slot the tape currently in the
- drive needs to go back to.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="supported-cdrom-drives">
- <para xml:lang="en">Which CD-ROM and CD-RW drives are supported by
- FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Any SCSI drive connected to a supported controller
- is supported. Most ATAPI compatible IDE CD-ROMs are
- supported.</para>
-
- <para xml:lang="en">FreeBSD supports any ATAPI-compatible IDE CD-R or CD-RW
- drive.</para>
-
- <para xml:lang="en">FreeBSD also supports any SCSI CD-R or CD-RW drives.
- Install the <package>sysutils/cdrtools</package> port or
- package, then use <command>cdrecord</command>.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </sect1>
-
- <sect1 xml:id="compatibility-kbd-mice">
- <title xml:lang="en">Keyboards and Mice</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="moused">
- <para xml:lang="en">Is it possible to use a mouse outside the
- X Window system?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The default console driver,
- <citerefentry><refentrytitle>syscons</refentrytitle><manvolnum>4</manvolnum></citerefentry>, provides the ability to use a mouse
- pointer in text consoles to cut &amp; paste text. Run
- the mouse daemon, <citerefentry><refentrytitle>moused</refentrytitle><manvolnum>8</manvolnum></citerefentry>, and turn on the mouse
- pointer in the virtual console:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>moused -p /dev/xxxx -t yyyy</userinput>
-<prompt>#</prompt> <userinput>vidcontrol -m on</userinput></screen>
-
- <para xml:lang="en">Where <replaceable>xxxx</replaceable> is the mouse
- device name and <replaceable>yyyy</replaceable> is a
- protocol type for the mouse. The mouse daemon can
- automatically determine the protocol type of most mice,
- except old serial mice. Specify the
- <literal>auto</literal> protocol to invoke automatic
- detection. If automatic detection does not work, see
- the <citerefentry><refentrytitle>moused</refentrytitle><manvolnum>8</manvolnum></citerefentry> manual page for a list of supported
- protocol types.</para>
-
- <para xml:lang="en">For a PS/2 mouse, add
- <literal>moused_enable="YES"</literal> to
- <filename>/etc/rc.conf</filename> to start the mouse
- daemon at boot time. Additionally, to
- use the mouse daemon on all virtual terminals instead of
- just the console, add <literal>allscreens_flags="-m
- on"</literal> to
- <filename>/etc/rc.conf</filename>.</para>
-
- <para xml:lang="en">When the mouse daemon is running, access to the
- mouse must be coordinated between the mouse daemon and
- other programs such as X Windows. Refer to the
- <acronym>FAQ</acronym>
- <link linkend="x-and-moused">Why does my mouse not work
- with X?</link> for more details on this issue.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="text-mode-cut-paste">
- <para xml:lang="en">How do I cut and paste text with a mouse in the text
- console?</para>
- </question>
-
- <answer>
- <para xml:lang="en">It is not possible to remove data using the mouse.
- However, it is possible to copy and paste. Once the
- mouse daemon is running as described in the <link linkend="moused">previous question</link>, hold down
- button 1 (left button) and move the mouse to select a
- region of text. Then, press button 2 (middle button) to
- paste it at the text cursor. Pressing button 3 (right
- button) will <quote>extend</quote> the selected region
- of text.</para>
-
- <para xml:lang="en">If the mouse does not have a middle button, it is
- possible to emulate one or remap buttons using mouse
- daemon options. See the <citerefentry><refentrytitle>moused</refentrytitle><manvolnum>8</manvolnum></citerefentry> manual page for
- details.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="mouse-wheel-buttons">
- <para xml:lang="en">My mouse has a fancy wheel and buttons. Can I use
- them in FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The answer is, unfortunately, <quote>It
- depends</quote>. These mice with additional features
- require specialized driver in most cases. Unless the
- mouse device driver or the user program has specific
- support for the mouse, it will act just like a standard
- two, or three button mouse.</para>
-
- <para xml:lang="en">For the possible usage of wheels in the X Window
- environment, refer to <link linkend="x-and-wheel">that section</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="keyboard-delete-key">
- <para xml:lang="en">How do I use my delete key in <command>sh</command>
- and <command>csh</command>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">For the <application>Bourne Shell</application>, add
- the following lines to <filename>~/.shrc</filename>.
- See <citerefentry><refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum></citerefentry> and <citerefentry><refentrytitle>editrc</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
-
- <programlisting xml:lang="en">bind ^? ed-delete-next-char # for console
-bind ^[[3~ ed-delete-next-char # for xterm</programlisting>
-
- <para xml:lang="en">For the <application>C Shell</application>, add the
- following lines to <filename>~/.cshrc</filename>.
- See <citerefentry><refentrytitle>csh</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
-
- <programlisting xml:lang="en">bindkey ^? delete-char # for console
-bindkey ^[[3~ delete-char # for xterm</programlisting>
-
- <para xml:lang="en">For more information, see <link xlink:href="http://www.ibb.net/~anne/keyboard.html">this
- page</link>.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </sect1>
-
- <sect1 xml:id="compatibility-other">
- <title xml:lang="en">Other Hardware</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="es1370-silent-pcm">
- <para xml:lang="en">Workarounds for no sound from my <citerefentry><refentrytitle>pcm</refentrytitle><manvolnum>4</manvolnum></citerefentry> sound
- card?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Some sound cards set their output volume to 0 at
- every boot. Run the following command every time the
- machine boots:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>mixer pcm 100 vol 100 cd 100</userinput></screen>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="power-management-support">
- <para xml:lang="en">Does FreeBSD support power management on my
- laptop?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FreeBSD supports the <acronym>ACPI</acronym> features
- found in modern hardware. Further information can be
- found in <citerefentry><refentrytitle>acpi</refentrytitle><manvolnum>4</manvolnum></citerefentry>.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </sect1>
- </chapter>
-
- <chapter xml:id="troubleshoot">
- <title xml:lang="en">Troubleshooting</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="pae">
- <para xml:lang="en">Why is FreeBSD finding the wrong amount of memory on
- <trademark>i386</trademark> hardware?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The most likely reason is the difference between
- physical memory addresses and virtual addresses.</para>
-
- <para xml:lang="en">The convention for most PC hardware is to use the
- memory area between 3.5 GB and 4 GB for a
- special purpose (usually for PCI). This address space is
- used to access PCI hardware. As a result real, physical
- memory cannot be accessed by that address space.</para>
-
- <para xml:lang="en">What happens to the memory that should appear in that
- location is hardware dependent. Unfortunately,
- some hardware does nothing and the ability to use that
- last 500 MB of RAM is entirely lost.</para>
-
- <para xml:lang="en">Luckily, most hardware remaps the memory to a higher
- location so that it can still be used. However, this can
- cause some confusion when watching the boot
- messages.</para>
-
- <para xml:lang="en">On a 32-bit version of FreeBSD, the memory appears lost,
- since it will be remapped above 4 GB, which a 32-bit
- kernel is unable to access. In this case, the solution is
- to build a PAE enabled kernel. See the entry on memory
- limits for more information.</para>
-
- <para xml:lang="en">On a 64-bit version of FreeBSD, or when running a
- PAE-enabled kernel, FreeBSD will correctly detect and remap
- the memory so it is usable. During boot, however, it may
- seem as if FreeBSD is detecting more memory than the system
- really has, due to the described remapping. This is
- normal and the available memory will be corrected as the
- boot process completes.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="signal11">
- <para xml:lang="en">Why do my programs occasionally die with
- <errorname>Signal 11</errorname> errors?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Signal 11 errors are caused when a process has
- attempted to access memory which the operating system has
- not granted it access to. If something like this is
- happening at seemingly random intervals,
- start investigating the cause.</para>
-
- <para xml:lang="en">These problems can usually be attributed to
- either:</para>
-
- <orderedlist>
- <listitem>
- <para xml:lang="en">If the problem is occurring only in a specific
- custom application, it is
- probably a bug in the code.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">If it is a problem with part of the base FreeBSD
- system, it may also be buggy code, but more often than
- not these problems are found and fixed long before us
- general <acronym>FAQ</acronym> readers get to use
- these bits of code (that is what -CURRENT is
- for).</para>
- </listitem>
- </orderedlist>
-
- <para xml:lang="en">It is probably
- not a FreeBSD bug if the
- problem occurs compiling a program, but the activity
- that the compiler is carrying out changes each
- time.</para>
-
- <para xml:lang="en">For example, if <command>make
- buildworld</command> fails while trying
- to compile <filename>ls.c</filename> into
- <filename>ls.o</filename> and, when run again, it fails
- in the same place, this is a broken build. Try
- updating source and try again. If the compile fails
- elsewhere, it is almost certainly due to hardware.</para>
-
- <para xml:lang="en">In the first case, use a debugger such as
- <citerefentry><refentrytitle>gdb</refentrytitle><manvolnum>1</manvolnum></citerefentry> to find the point in the program which is
- attempting to access a bogus address and fix
- it.</para>
-
- <para xml:lang="en">In the second case, verify which piece of
- hardware is at fault.</para>
-
- <para xml:lang="en">Common causes of this include:</para>
-
- <orderedlist>
- <listitem>
- <para xml:lang="en">The hard disks might be overheating: Check that
- the fans are still working, as the disk and
- other hardware might be overheating.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">The processor running is overheating: This might
- be because the processor has been overclocked, or the
- fan on the processor might have died. In either case,
- ensure that the hardware is running at
- what it is specified to run at, at least while trying
- to solve this problem. If it is not, clock it back
- to the default settings.)</para>
-
- <para xml:lang="en">Regarding overclocking, it is far
- cheaper to have a slow system than a fried system that
- needs replacing! Also the community is not
- sympathetic to problems on overclocked systems.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Dodgy memory: if multiple memory
- SIMMS/DIMMS are installed, pull them all out and try
- running the machine with each SIMM or DIMM
- individually to narrow the problem down to either the
- problematic DIMM/SIMM or perhaps even a
- combination.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Over-optimistic motherboard settings: the BIOS
- settings, and some motherboard jumpers, provide
- options to set various timings. The defaults
- are often sufficient, but sometimes setting the wait
- states on RAM too low, or setting the <quote>RAM
- Speed: Turbo</quote> option
- will cause strange behavior. A possible idea is to
- set to BIOS defaults, after noting
- the current settings first.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Unclean or insufficient power to the motherboard.
- Remove any unused I/O boards, hard disks, or
- CD-ROMs,
- or disconnect the power cable from them, to see if
- the power supply can manage a smaller load. Or try
- another power supply, preferably one with a little
- more power. For instance, if the current power supply
- is rated at 250 Watts, try one rated at
- 300 Watts.</para>
- </listitem>
- </orderedlist>
-
- <para xml:lang="en">Read the section on
- <link linkend="signal11">Signal 11</link> for a further
- explanation and a discussion on how memory testing
- software or hardware can still pass faulty memory. There
- is an extensive <acronym>FAQ</acronym> on this at <link xlink:href="http://www.bitwizard.nl/sig11/">the SIG11
- problem <acronym>FAQ</acronym></link>.</para>
-
- <para xml:lang="en">Finally, if none of this has helped, it is possibly
- a bug in FreeBSD.
- Follow <link linkend="access-pr">these instructions</link>
- to send a problem report.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="trap-12-panic">
- <para xml:lang="en">My system crashes with either <errorname>Fatal trap
- 12: page fault in kernel mode</errorname>, or
- <errorname>panic:</errorname>, and spits out a bunch of
- information. What should I do?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The FreeBSD developers are interested in these
- errors, but need more information than just the error
- message. Copy the full crash message. Then consult the
- <acronym>FAQ</acronym> section on <link linkend="kernel-panic-troubleshooting">kernel
- panics</link>, build a debugging kernel, and get a
- backtrace. This might sound difficult, but does not
- require any programming skills. Just follow the
- instructions.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="proc-table-full">
- <para xml:lang="en">What is the meaning of the error <errorname>maxproc
- limit exceeded by uid %i, please see tuning(7) and
- login.conf(5)</errorname>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The FreeBSD kernel will only allow a certain number of
- processes to exist at one time. The number is based on
- the <varname>kern.maxusers</varname> <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- variable. <varname>kern.maxusers</varname> also affects
- various other in-kernel limits, such as network buffers.
- If the machine is heavily loaded,
- increase <varname>kern.maxusers</varname>. This will
- increase these other system limits in addition to the
- maximum number of processes.</para>
-
- <para xml:lang="en">To adjust the <varname>kern.maxusers</varname> value,
- see the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/configtuning-kernel-limits.html#kern-maxfiles">File/Process
- Limits</link> section of the Handbook. While that
- section refers to open files, the same limits apply to
- processes.</para>
-
- <para xml:lang="en">If the machine is lightly loaded but running a very
- large number of processes, adjust the
- <varname>kern.maxproc</varname> tunable by defining it in
- <filename>/boot/loader.conf</filename>. The tunable will
- not get adjusted until the system is rebooted. For more
- information about tuning tunables, see
- <citerefentry><refentrytitle>loader.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If these processes are being run by
- a single user, adjust
- <varname>kern.maxprocperuid</varname> to be one less than
- the new <varname>kern.maxproc</varname> value. It must
- be at least one less because one system program,
- <citerefentry><refentrytitle>init</refentrytitle><manvolnum>8</manvolnum></citerefentry>, must always be running.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="remote-fullscreen">
- <para xml:lang="en">Why do full screen applications on remote machines
- misbehave?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The remote machine may be setting the terminal type to
- something other than <literal>xterm</literal> which is
- required by the FreeBSD console. Alternatively the kernel
- may have the wrong values for the width and height of the
- terminal.</para>
-
- <para xml:lang="en">Check the value of the <envar>TERM</envar>
- environment variable is <literal>xterm</literal>. If the
- remote machine does not support that try
- <literal>vt100</literal>.</para>
-
- <para xml:lang="en">Run <command>stty -a</command> to check what the
- kernel thinks the terminal dimensions are. If they are
- incorrect, they can be changed by running
- <command>stty rows <replaceable>RR</replaceable> cols
- <replaceable>CC</replaceable></command>.</para>
-
- <para xml:lang="en">Alternatively, if the client machine has
- <package>x11/xterm</package> installed, then running
- <command>resize</command> will query the terminal for the
- correct dimensions and set them.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="connection-delay">
- <para xml:lang="en">Why does it take so long to connect to my computer via
- <command>ssh</command> or
- <command>telnet</command>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The symptom: there is a long delay between the time
- the TCP connection is established and the time when the
- client software asks for a password (or, in
- <citerefentry><refentrytitle>telnet</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s case, when a login prompt
- appears).</para>
-
- <para xml:lang="en">The problem: more likely than not, the delay is caused
- by the server software trying to resolve the client's IP
- address into a hostname. Many servers, including the
- <application>Telnet</application> and
- <application>SSH</application> servers that come with
- FreeBSD, do this to store the hostname in a log file for
- future reference by the administrator.</para>
-
- <para xml:lang="en">The remedy: if the problem occurs whenever connecting
- the client computer to any server, the problem
- is with the client. If the problem only occurs
- when someone connects to the server computer, the
- problem is with the server.</para>
-
- <para xml:lang="en">If the problem is with the client, the only remedy is
- to fix the DNS so the server can resolve it. If this is
- on a local network, consider it a server problem and keep
- reading. If this is on the Internet,
- contact your ISP.</para>
-
- <para xml:lang="en">If the problem is with the server on a
- local network, configure the server
- to resolve address-to-hostname queries for the local
- address range. See <citerefentry><refentrytitle>hosts</refentrytitle><manvolnum>5</manvolnum></citerefentry> and <citerefentry><refentrytitle>named</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- for more information. If this is on the
- Internet, the problem may be that the local server's
- resolver is not functioning correctly. To check, try to
- look up another host such as
- <systemitem>www.yahoo.com</systemitem>. If it does not
- work, that is the problem.</para>
-
- <para xml:lang="en">Following a fresh install of FreeBSD, it is also possible
- that domain and name server information is missing from
- <filename>/etc/resolv.conf</filename>. This will often
- cause a delay in <application>SSH</application>, as the
- option <literal>UseDNS</literal> is set to
- <literal>yes</literal> by default in
- <filename>/etc/ssh/sshd_config</filename>. If this is
- causing the problem, either fill in the
- missing information in
- <filename>/etc/resolv.conf</filename> or set
- <literal>UseDNS</literal> to <literal>no</literal> in
- <filename>sshd_config</filename> as a temporary
- workaround.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="file-table-full">
- <para xml:lang="en">Why does <errorname>file: table is full</errorname>
- show up repeatedly in <citerefentry><refentrytitle>dmesg</refentrytitle><manvolnum>8</manvolnum></citerefentry>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This error message indicates that the number of
- available file descriptors have been exhausted on the
- system. Refer to the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/configtuning-kernel-limits.html#kern-maxfiles">kern.maxfiles</link>
- section of the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/configtuning-kernel-limits.html">Tuning
- Kernel Limits</link> section of the Handbook for a
- discussion and solution.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="computer-clock-skew">
- <para xml:lang="en">Why does the clock on my computer keep incorrect
- time?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The computer has two or more clocks, and FreeBSD has
- chosen to use the wrong one.</para>
-
- <para xml:lang="en">Run <citerefentry><refentrytitle>dmesg</refentrytitle><manvolnum>8</manvolnum></citerefentry>, and check for lines that contain
- <literal>Timecounter</literal>. The one with the highest
- quality value that FreeBSD chose.</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>dmesg | grep Timecounter</userinput>
-Timecounter "i8254" frequency 1193182 Hz quality 0
-Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000
-Timecounter "TSC" frequency 2998570050 Hz quality 800
-Timecounters tick every 1.000 msec</screen>
-
- <para xml:lang="en">Confirm this by checking the
- <varname>kern.timecounter.hardware</varname>
- <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>sysctl kern.timecounter.hardware</userinput>
-kern.timecounter.hardware: ACPI-fast</screen>
-
- <para xml:lang="en">It may be a broken ACPI timer. The simplest solution
- is to disable the ACPI timer in
- <filename>/boot/loader.conf</filename>:</para>
-
- <programlisting xml:lang="en">debug.acpi.disabled="timer"</programlisting>
-
- <para xml:lang="en">Or the BIOS may modify the TSC clock—perhaps to
- change the speed of the processor when running from
- batteries, or going into a power saving mode, but FreeBSD is
- unaware of these adjustments, and appears to gain or lose
- time.</para>
-
- <para xml:lang="en">In this example, the <literal>i8254</literal> clock is
- also available, and can be selected by writing its name to
- the <varname>kern.timecounter.hardware</varname>
- <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>sysctl kern.timecounter.hardware=i8254</userinput>
-kern.timecounter.hardware: TSC -&gt; i8254</screen>
-
- <para xml:lang="en">The computer should now start keeping more accurate
- time.</para>
-
- <para xml:lang="en">To have this change automatically run at boot time,
- add the following line to
- <filename>/etc/sysctl.conf</filename>:</para>
-
- <programlisting xml:lang="en">kern.timecounter.hardware=i8254</programlisting>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="indefinite-wait-buffer">
- <para xml:lang="en">What does the error <errorname>swap_pager: indefinite
- wait buffer:</errorname> mean?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This means that a process is trying to page memory
- from
- disk, and the page attempt has hung trying to access the
- disk for more than 20 seconds. It might be caused by bad
- blocks on the disk drive, disk wiring, cables, or any
- other disk I/O-related hardware. If the drive itself is
- bad, disk errors will appear in
- <filename>/var/log/messages</filename> and in the output
- of <command>dmesg</command>. Otherwise, check the cables
- and connections.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="lock-order-reversal">
- <para xml:lang="en">What is a <errorname>lock order
- reversal</errorname>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The FreeBSD kernel uses a number of resource locks to
- arbitrate contention for certain resources. When multiple
- kernel threads try to obtain multiple resource locks,
- there's always the potential for a deadlock, where two
- threads have each obtained one of the locks and blocks
- forever waiting for the other thread to release one of the
- other locks. This sort of locking problem can be avoided
- if all threads obtain the locks in the same order.</para>
-
- <para xml:lang="en">A run-time lock diagnostic system called
- <citerefentry><refentrytitle>witness</refentrytitle><manvolnum>4</manvolnum></citerefentry>, enabled in FreeBSD-CURRENT and disabled by
- default for stable branches and releases, detects the
- potential for deadlocks due to locking errors, including
- errors caused by obtaining multiple resource locks with a
- different order from different parts of the kernel. The
- <citerefentry><refentrytitle>witness</refentrytitle><manvolnum>4</manvolnum></citerefentry> framework tries to detect this problem as
- it happens, and reports it by printing a message to the
- system console about a <errorname>lock order
- reversal</errorname> (often referred to also as
- <acronym>LOR</acronym>).</para>
-
- <para xml:lang="en">It is possible to get false positives, as
- <citerefentry><refentrytitle>witness</refentrytitle><manvolnum>4</manvolnum></citerefentry> is conservative. A true positive report
- <emphasis>does not</emphasis> mean that a system is
- dead-locked; instead it should be understood as a warning
- that a deadlock could have happened here.</para>
-
- <note>
- <para xml:lang="en">Problematic <acronym>LOR</acronym>s tend to get
- fixed quickly, so check the <link xlink:href="http://lists.FreeBSD.org/mailman/listinfo/freebsd-current">FreeBSD-CURRENT mailing list</link> before posting
- to it.</para>
- </note>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="called-with-non-sleepable-locks-held">
- <para xml:lang="en">What does <errorname>Called ... with the following
- non-sleepable locks held</errorname> mean?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This means that a function that may sleep was called
- while a mutex (or other unsleepable) lock was held.</para>
-
- <para xml:lang="en">The reason this is an error is because mutexes are not
- intended to be held for long periods of time; they are
- supposed to only be held to maintain short periods of
- synchronization. This programming contract allows device
- drivers to use mutexes to synchronize with the rest of the
- kernel during interrupts. Interrupts (under FreeBSD) may not
- sleep. Hence it is imperative that no subsystem in the
- kernel block for an extended period while holding a
- mutex.</para>
-
- <para xml:lang="en">To catch such errors, assertions may be added to the
- kernel that interact with the <citerefentry><refentrytitle>witness</refentrytitle><manvolnum>4</manvolnum></citerefentry> subsystem to
- emit a warning or fatal error (depending on the system
- configuration) when a potentially blocking call is made
- while holding a mutex.</para>
-
- <para xml:lang="en">In summary, such warnings are non-fatal, however with
- unfortunate timing they could cause undesirable effects
- ranging from a minor blip in the system's responsiveness
- to a complete system lockup.</para>
-
- <para xml:lang="en">For additional information about locking in FreeBSD see
- <citerefentry><refentrytitle>locking</refentrytitle><manvolnum>9</manvolnum></citerefentry>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="touch-not-found">
- <para xml:lang="en">Why does
- <buildtarget xml:lang="en">buildworld</buildtarget>/<buildtarget xml:lang="en">installworld</buildtarget>
- die with the message <errorname>touch: not
- found</errorname>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This error does not mean that the <citerefentry><refentrytitle>touch</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- utility is missing. The error is instead probably due to
- the dates of the files being set sometime in the future.
- If the CMOS clock is set to local time, run
- <command>adjkerntz -i</command> to adjust
- the kernel clock when booting into single-user
- mode.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="applications">
- <title xml:lang="en">User Applications</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="user-apps">
- <para xml:lang="en">Where are all the user applications?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Refer to <link xlink:href="@@URL_RELPREFIX@@/ports/index.html">the ports
- page</link> for info on software packages ported to
- FreeBSD. The list currently tops 24,000 and is
- growing daily, so come back to check often or subscribe to
- the <link xlink:href="http://lists.FreeBSD.org/mailman/listinfo/freebsd-announce">FreeBSD announcements mailing list</link> for periodic updates on new
- entries.</para>
-
- <para xml:lang="en">Most ports should work on all supported versions of
- FreeBSD. Those that do not are specifically marked as such.
- Each time a FreeBSD release is made, a snapshot of the ports
- tree at the time of release in also included in the
- <filename>ports/</filename> directory.</para>
-
- <para xml:lang="en">FreeBSD supports compressed binary packages to easily
- install and uninstall ports. Use <citerefentry><refentrytitle>pkg</refentrytitle><manvolnum>7</manvolnum></citerefentry> to control
- the installation of packages.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="how-do-download-ports-tree">
- <para xml:lang="en">How do I download the Ports tree? Should I be using
- Subversion?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Any of the methods listed here work:</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en">Use portsnap for most use cases. Refer to <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/ports-using.html">Using
- the Ports Collection</link> for instructions on how to
- use this tool.</para>
- </listitem>
- <listitem>
- <para xml:lang="en">Use Subversion if custom patches to the
- ports tree are needed. Refer to <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/svn.html">Using
- Subversion</link> for details.</para>
- </listitem>
- </itemizedlist>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="java">
- <para xml:lang="en">Does FreeBSD support <trademark>Java</trademark>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes. Refer to <link xlink:href="@@URL_RELPREFIX@@/java/index.html">https://www.FreeBSD.org/java/</link>
- for more information.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ports-4x">
- <para xml:lang="en">Why can I not build this port on my
- 11.<replaceable>X</replaceable> -, or
- 12.<replaceable>X</replaceable> -STABLE machine?</para>
- </question>
-
- <answer>
- <para xml:lang="en">If the installed FreeBSD version lags significantly
- behind <emphasis>-CURRENT</emphasis> or
- <emphasis>-STABLE</emphasis>, update the Ports Collection
- using the instructions in <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/ports-using.html">Using
- the Ports Collection</link>. If the system is
- up-to-date, someone might have committed a change to the
- port which works for <emphasis>-CURRENT</emphasis> but
- which broke the port for <emphasis>-STABLE</emphasis>.
- <link xlink:href="https://bugs.FreeBSD.org/submit/">Submit</link>
- a bug report, since the Ports Collection is supposed to
- work for both the <emphasis>-CURRENT</emphasis> and
- <emphasis>-STABLE</emphasis> branches.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="make-index">
- <para xml:lang="en">I just tried to build <filename>INDEX</filename> using
- <command>make index</command>, and it failed. Why?</para>
- </question>
-
- <answer>
- <para xml:lang="en">First, make sure that the Ports Collection is
- up-to-date. Errors that affect building
- <filename>INDEX</filename> from an up-to-date copy of the
- Ports Collection are high-visibility and are thus almost
- always fixed immediately.</para>
-
- <para xml:lang="en">There are rare cases where <filename>INDEX</filename>
- will not build due to odd cases involving
- <varname>OPTIONS_SET</varname>
- being set in <filename>make.conf</filename>. If
- you suspect that this is the case, try to make
- <filename>INDEX</filename> with those variables
- turned off before reporting it to <link xlink:href="http://lists.FreeBSD.org/mailman/listinfo/freebsd-ports">FreeBSD ports mailing list</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ports-update">
- <para xml:lang="en">I updated the sources, now how do I update my
- installed ports?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FreeBSD does not include a port upgrading tool, but it
- does have some tools to make the upgrade process somewhat
- easier. Additional tools are available to simplify
- port handling and are described the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/ports-using.html">Upgrading
- Ports</link> section in the FreeBSD Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ports-major-upgrade">
- <para xml:lang="en">Do I need to recompile every port each time I perform
- a major version update?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes! While a recent system will run with
- software compiled under an older release,
- things will randomly crash and fail to work once
- other ports are installed or updated.</para>
-
- <para xml:lang="en">When the system is upgraded, various shared libraries,
- loadable modules, and other parts of the system will be
- replaced with newer versions. Applications linked against
- the older versions may fail to start or, in other cases,
- fail to function properly.</para>
-
- <para xml:lang="en">For more information, see <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/updating-upgrading-freebsdupdate.html#freebsdupdate-upgrade">the
- section on upgrades</link> in the FreeBSD Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ports-minor-upgrade">
- <para xml:lang="en">Do I need to recompile every port each time I perform
- a minor version update?</para>
- </question>
-
- <answer>
- <para xml:lang="en">In general, no. FreeBSD developers do their utmost to
- guarantee binary compatibility across all releases with
- the same major version number. Any exceptions will be
- documented in the Release Notes, and advice given there
- should be followed.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="minimal-sh">
- <para xml:lang="en">Why is <command>/bin/sh</command> so minimal? Why
- does FreeBSD not use <command>bash</command> or another
- shell?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Many people need to write shell scripts which will be
- portable across many systems. That is why <trademark class="registered">POSIX</trademark>
- specifies the shell and utility commands in great detail.
- Most scripts are written in Bourne shell (<citerefentry><refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum></citerefentry>), and
- because several important programming interfaces
- (<citerefentry><refentrytitle>make</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>system</refentrytitle><manvolnum>3</manvolnum></citerefentry>, <citerefentry><refentrytitle>popen</refentrytitle><manvolnum>3</manvolnum></citerefentry>, and
- analogues in higher-level scripting languages like Perl
- and Tcl) are specified to use the Bourne shell to
- interpret commands. Because the Bourne shell is so often
- and widely used, it is important for it to be quick to
- start, be deterministic in its behavior, and have a small
- memory footprint.</para>
-
- <para xml:lang="en">The existing implementation is our best effort at
- meeting as many of these requirements simultaneously as we
- can. To keep <command>/bin/sh</command> small, we have
- not provided many of the convenience features that other
- shells have. That is why other more featureful shells
- like <command>bash</command>, <command>scsh</command>,
- <citerefentry><refentrytitle>tcsh</refentrytitle><manvolnum>1</manvolnum></citerefentry>, and <command>zsh</command> are available.
- Compare the memory utilization of
- these shells by looking at the <quote>VSZ</quote> and
- <quote>RSS</quote> columns in a <command>ps -u</command>
- listing.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="midi-sound-files">
- <para xml:lang="en">How do I create audio CDs from my MIDI files?</para>
- </question>
-
- <answer>
- <para xml:lang="en">To create audio CDs from MIDI files, first install
- <package>audio/timidity++</package> from ports then
- install manually the GUS patches set by Eric A. Welsh,
- available at <uri xlink:href="http://alleg.sourceforge.net/digmid.html">http://alleg.sourceforge.net/digmid.html</uri>.
- After <application>TiMidity++</application> has been
- installed properly, MIDI files may be converted to WAV
- files with the following command line:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>timidity -Ow -s 44100 -o /tmp/juke/01.wav 01.mid</userinput></screen>
-
- <para xml:lang="en">The WAV files can then be converted to other formats
- or burned onto audio CDs, as described in the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/creating-cds.html">FreeBSD
- Handbook</link>.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="kernelconfig">
- <title xml:lang="en">Kernel Configuration</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="make-kernel">
- <para xml:lang="en">I would like to customize my kernel. Is it
- difficult?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Not at all! Check out the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html">kernel
- config section of the Handbook</link>.</para>
-
- <note>
- <para xml:lang="en">The new <filename>kernel</filename> will be
- installed to the <filename>/boot/kernel</filename>
- directory along with its modules, while the old kernel
- and its modules will be moved to the
- <filename>/boot/kernel.old</filename> directory. If
- a mistake is made in the
- configuration, simply boot the previous version of the
- kernel.</para>
- </note>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="why-kernel-big">
- <para xml:lang="en">Why is my kernel so big?</para>
- </question>
-
- <answer>
- <para xml:lang="en"><literal>GENERIC</literal> kernels shipped with FreeBSD
- are compiled in <emphasis>debug mode</emphasis>.
- Kernels built in debug mode contain debug data in
- separate files that are used for debugging.
- FreeBSD releases prior to 11.0 store these debug files in
- the same directory as the kernel itself,
- <filename>/boot/kernel/</filename>.
- In FreeBSD 11.0 and later the debug files are stored in
- <filename>/usr/lib/debug/boot/kernel/</filename>.
- Note that there will be little or no performance loss from
- running a debug kernel, and it is useful to keep one
- around in case of a system panic.</para>
-
- <para xml:lang="en">When running low on disk space, there
- are different options to reduce the size of
- <filename>/boot/kernel/</filename> and
- <filename>/usr/lib/debug/</filename>.</para>
-
- <para xml:lang="en">To not install the symbol files,
- make sure the following line exists in
- <filename>/etc/src.conf</filename>:</para>
-
- <programlisting xml:lang="en">WITHOUT_KERNEL_SYMBOLS=yes</programlisting>
-
- <para xml:lang="en">For more information see <citerefentry><refentrytitle>src.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
-
- <para xml:lang="en">If you want to avoid building debug files altogether,
- make sure that both of the following are true:</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en">This line does not exist in the kernel
- configuration file:</para>
-
- <programlisting xml:lang="en">makeoptions DEBUG=-g</programlisting>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Do not run <citerefentry><refentrytitle>config</refentrytitle><manvolnum>8</manvolnum></citerefentry> with
- <option>-g</option>.</para>
- </listitem>
- </itemizedlist>
-
- <para xml:lang="en">Either of the above settings will cause the kernel to
- be built in debug mode.</para>
-
- <para xml:lang="en">To build and install only the specified modules, list
- them in
- <filename>/etc/make.conf</filename>:</para>
-
- <programlisting xml:lang="en">MODULES_OVERRIDE= <replaceable>accf_http ipfw</replaceable></programlisting>
-
- <para xml:lang="en">Replace <emphasis>accf_httpd ipfw</emphasis> with a
- list of needed modules. Only the listed modules will be
- built. This reduces the size of the kernel
- directory and decreases the amount of time needed to
- build the kernel. For more information, read
- <filename>/usr/share/examples/etc/make.conf</filename>.</para>
-
- <para xml:lang="en">Unneeded devices can be removed from the kernel
- to further reduce the size. See <xref linkend="make-kernel"/> for more information.</para>
-
- <para xml:lang="en">To put any of these options into effect, follow the
- instructions to <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/kernelconfig-building.html">build
- and install</link> the new kernel.</para>
-
- <para xml:lang="en">For reference, the FreeBSD 11 amd64 kernel
- (<filename>/boot/kernel/kernel</filename>) is
- approximately 25 MB.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="generic-kernel-build-failure">
- <para xml:lang="en">Why does every kernel I try to build fail to compile,
- even <filename>GENERIC</filename>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">There are a number of possible causes for this
- problem:</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en">The source
- tree is different from the one used to build the
- currently running system. When attempting an upgrade,
- read <filename>/usr/src/UPDATING</filename>, paying
- particular attention to the <quote>COMMON
- ITEMS</quote> section at the end.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">The <command>make buildkernel</command> did not
- complete successfully. The <command>make
- buildkernel</command> target relies on files
- generated by the <command>make buildworld</command>
- target to complete its job correctly.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Even when building <link linkend="stable">FreeBSD-STABLE</link>, it is possible
- that the source tree was fetched at a time when it was
- either being modified or it was broken.
- Only releases are guaranteed to be
- buildable, although <link linkend="stable">FreeBSD-STABLE</link> builds fine the
- majority of the time. Try re-fetching the source tree
- and see if the problem goes away. Try using a
- different mirror in case the previous one is having
- problems.</para>
- </listitem>
- </itemizedlist>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="scheduler-in-use">
- <para xml:lang="en">Which scheduler is in use on a
- running system?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The name of the scheduler currently being used is
- directly available as the value of the
- <varname>kern.sched.name</varname> sysctl:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> sysctl <replaceable>kern.sched.name</replaceable>
-kern.sched.name: ULE</screen>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="scheduler-kern-quantum">
- <para xml:lang="en">What is <varname>kern.sched.quantum</varname>?</para>
- </question>
-
- <answer>
- <para xml:lang="en"><varname>kern.sched.quantum</varname> is the maximum
- number of ticks a process can run without being preempted
- in the 4BSD scheduler.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="disks">
- <title xml:lang="en">Disks, File Systems, and Boot Loaders</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="adding-disks">
- <para xml:lang="en">How can I add my new hard disk to my FreeBSD
- system?</para>
- </question>
-
- <answer>
- <para xml:lang="en">See the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/disks-adding.html">Adding
- Disks</link> section in the FreeBSD Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="new-huge-disk">
- <para xml:lang="en">How do I move my system over to my huge new
- disk?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The best way is to reinstall the operating system on
- the new disk, then move the user data over. This is
- highly recommended when tracking
- <emphasis>-STABLE</emphasis> for more than one release or
- when updating a release instead of installing a new one.
- Install booteasy on both disks with <citerefentry><refentrytitle>boot0cfg</refentrytitle><manvolnum>8</manvolnum></citerefentry> and
- dual boot until you are happy with the new configuration.
- Skip the next paragraph to find out how to move the data
- after doing this.</para>
-
- <para xml:lang="en">Alternatively, partition and label the new disk with
- either <citerefentry><refentrytitle>sade</refentrytitle><manvolnum>8</manvolnum></citerefentry> or <citerefentry><refentrytitle>gpart</refentrytitle><manvolnum>8</manvolnum></citerefentry>. If the disks are
- MBR-formatted, booteasy can be installed on both disks
- with <citerefentry><refentrytitle>boot0cfg</refentrytitle><manvolnum>8</manvolnum></citerefentry> so that the computer can dual boot
- to the old or new system after the copying is done.</para>
-
- <para xml:lang="en">Once the new disk set up,
- the data cannot just be copied. Instead, use tools that
- understand device files and system flags, such as
- <citerefentry><refentrytitle>dump</refentrytitle><manvolnum>8</manvolnum></citerefentry>. Although it is recommended
- to move the data while in single-user mode, it
- is not required.</para>
-
- <para xml:lang="en">When the disks are formatted with
- <acronym>UFS</acronym>, never use anything but
- <citerefentry><refentrytitle>dump</refentrytitle><manvolnum>8</manvolnum></citerefentry> and <citerefentry><refentrytitle>restore</refentrytitle><manvolnum>8</manvolnum></citerefentry> to move the root file
- system. These commands should also be used when moving a
- single partition to another empty partition. The sequence
- of steps to use <command>dump</command> to move the data
- from one <acronym>UFS</acronym> partitions to a new
- partition is:</para>
-
- <procedure>
- <step>
- <para xml:lang="en"><command>newfs</command> the new partition.</para>
- </step>
-
- <step>
- <para xml:lang="en"><command>mount</command> it on a temporary mount
- point.</para>
- </step>
-
- <step>
- <para xml:lang="en"><command>cd</command> to that directory.</para>
- </step>
-
- <step>
- <para xml:lang="en"><command>dump</command> the old partition, piping
- output to the new one.</para>
- </step>
- </procedure>
-
- <para xml:lang="en">For example, to move
- <filename>/dev/ada1s1a</filename> with
- <filename>/mnt</filename> as the temporary mount point,
- type:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>newfs /dev/ada1s1a</userinput>
-<prompt>#</prompt> <userinput>mount /dev/ada1s1a /mnt</userinput>
-<prompt>#</prompt> <userinput>cd /mnt</userinput>
-<prompt>#</prompt> <userinput>dump 0af - / | restore rf -</userinput></screen>
-
- <para xml:lang="en">Rearranging partitions with
- <command>dump</command> takes a bit more work. To merge a
- partition like <filename>/var</filename> into its parent,
- create the new partition large enough for both, move the
- parent partition as described above, then move the child
- partition into the empty directory that the first move
- created:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>newfs /dev/ada1s1a</userinput>
-<prompt>#</prompt> <userinput>mount /dev/ada1s1a /mnt</userinput>
-<prompt>#</prompt> <userinput>cd /mnt</userinput>
-<prompt>#</prompt> <userinput>dump 0af - / | restore rf -</userinput>
-<prompt>#</prompt> <userinput>cd var</userinput>
-<prompt>#</prompt> <userinput>dump 0af - /var | restore rf -</userinput></screen>
-
- <para xml:lang="en">To split a directory from its parent, say putting
- <filename>/var</filename> on its own partition when it was
- not before, create both partitions, then mount the child
- partition on the appropriate directory in the temporary
- mount point, then move the old single partition:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>newfs /dev/ada1s1a</userinput>
-<prompt>#</prompt> <userinput>newfs /dev/ada1s1d</userinput>
-<prompt>#</prompt> <userinput>mount /dev/ada1s1a /mnt</userinput>
-<prompt>#</prompt> <userinput>mkdir /mnt/var</userinput>
-<prompt>#</prompt> <userinput>mount /dev/ada1s1d /mnt/var</userinput>
-<prompt>#</prompt> <userinput>cd /mnt</userinput>
-<prompt>#</prompt> <userinput>dump 0af - / | restore rf -</userinput></screen>
-
- <para xml:lang="en">The <citerefentry><refentrytitle>cpio</refentrytitle><manvolnum>1</manvolnum></citerefentry> and <citerefentry><refentrytitle>pax</refentrytitle><manvolnum>1</manvolnum></citerefentry> utilities are also
- available for moving user data. These are known to lose
- file flag information, so use them with caution.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="safe-softupdates">
- <para xml:lang="en">Which partitions can safely use Soft Updates? I have
- heard that Soft Updates on <filename>/</filename> can
- cause problems. What about Journaled Soft Updates?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Short answer: Soft Updates can usually be safely used
- on all partitions.</para>
-
- <para xml:lang="en">Long answer: Soft Updates has two characteristics
- that may be undesirable on certain partitions. First, a
- Soft Updates partition has a small chance of losing data
- during a system crash. The partition will not be
- corrupted as the data will simply be lost. Second, Soft
- Updates can cause temporary space shortages.</para>
-
- <para xml:lang="en">When using Soft Updates, the kernel can take up to
- thirty seconds to write changes to the physical disk.
- When a large file is deleted the file still resides on
- disk until the kernel actually performs the deletion.
- This can cause a very simple race condition. Suppose
- one large file is deleted and another large file is
- immediately created. The first large file is not yet
- actually removed from the physical disk, so the disk might
- not have enough room for the second large file. This will
- produce an error that the partition does not have enough
- space, even though a large chunk of space has just been
- released. A few seconds later, the file creation works as
- expected.</para>
-
- <para xml:lang="en">If a system should crash after the kernel accepts a
- chunk of data for writing to disk, but before that data is
- actually written out, data could be lost. This risk is
- extremely small, but generally manageable.</para>
-
- <para xml:lang="en">These issues affect all partitions using Soft Updates.
- So, what does this mean for the root partition?</para>
-
- <para xml:lang="en">Vital information on the root partition changes very
- rarely. If the system crashed during the thirty-second
- window after such a change is made, it is possible that
- data could be lost. This risk is negligible for most
- applications, but be aware that it exists. If
- the system cannot tolerate this much risk, do not use
- Soft Updates on the root file system!</para>
-
- <para xml:lang="en"><filename>/</filename> is traditionally one of the
- smallest partitions. If
- <filename>/tmp</filename> is on
- <filename>/</filename>, there may be intermittent
- space problems. Symlinking <filename>/tmp</filename> to
- <filename>/var/tmp</filename> will solve this
- problem.</para>
-
- <para xml:lang="en">Finally, <citerefentry><refentrytitle>dump</refentrytitle><manvolnum>8</manvolnum></citerefentry> does not work in live mode (-L)
- on a filesystem, with Journaled Soft Updates
- (<acronym>SU+J</acronym>).</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="mount-foreign-fs">
- <para xml:lang="en">Can I mount other foreign file systems under
- FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FreeBSD supports a variety of other file systems.</para>
-
- <variablelist>
- <varlistentry>
- <term xml:lang="en">UFS</term>
-
- <listitem>
- <para xml:lang="en">UFS CD-ROMs can be mounted directly on FreeBSD.
- Mounting disk partitions from Digital UNIX and other
- systems that support UFS may be more complex,
- depending on the details of the disk partitioning
- for the operating system in question.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term xml:lang="en">ext2/ext3</term>
-
- <listitem>
- <para xml:lang="en">FreeBSD supports <literal>ext2fs</literal> and
- <literal>ext3fs</literal> partitions. See
- <citerefentry><refentrytitle>ext2fs</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term xml:lang="en">NTFS</term>
-
- <listitem>
- <para xml:lang="en">FUSE based NTFS support is available as a port
- (<package>sysutils/fusefs-ntfs</package>). For more
- information see <link xlink:href="http://www.tuxera.com/community/ntfs-3g-manual/"><application>ntfs-3g</application></link>.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term xml:lang="en">FAT</term>
-
- <listitem>
- <para xml:lang="en">FreeBSD includes a read-write FAT driver. For more
- information, see <citerefentry><refentrytitle>mount_msdosfs</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term xml:lang="en">ZFS</term>
-
- <listitem>
- <para>FreeBSD 包含由 <trademark>Sun</trademark> 移植過來的 ZFS 驅動程式。 目前的建議是僅在記憶體充足的 amd64 平臺上使用它。有關更詳細資訊, 請參閱 <citerefentry><refentrytitle>zfs</refentrytitle><manvolnum>8</manvolnum></citerefentry>。</para>
- </listitem>
- </varlistentry>
- </variablelist>
-
- <para xml:lang="en">FreeBSD includes the Network File System
- <acronym>NFS</acronym> and the FreeBSD Ports Collection
- provides several FUSE applications to support many other
- file systems.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="mount-dos">
- <para xml:lang="en">How do I mount a secondary DOS partition?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The secondary DOS partitions are found after
- <emphasis>all</emphasis> the primary partitions. For
- example, if <literal>E</literal> is the
- second DOS partition on the second SCSI drive, there will
- be a device file for <quote>slice 5</quote> in
- <filename>/dev</filename>. To mount it:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>mount -t msdosfs /dev/da1s5 /dos/e</userinput></screen>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="crypto-file-system">
- <para xml:lang="en">Is there a cryptographic file system for FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes, <citerefentry><refentrytitle>gbde</refentrytitle><manvolnum>8</manvolnum></citerefentry> and <citerefentry><refentrytitle>geli</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
- See the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/disks-encrypting.html">Encrypting
- Disk Partitions</link> section of the FreeBSD
- Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="grub-loader">
- <para xml:lang="en">How do I boot FreeBSD and <trademark class="registered">Linux</trademark> using
- <application>GRUB</application>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">To boot FreeBSD using <application>GRUB</application>,
- add the following to either
- <filename>/boot/grub/menu.lst</filename> or
- <filename>/boot/grub/grub.conf</filename>, depending upon
- which is used by the <trademark class="registered">Linux</trademark> distribution.</para>
-
- <programlisting xml:lang="en">title FreeBSD 9.1
- root <replaceable>(hd0,a)</replaceable>
- kernel /boot/loader</programlisting>
-
- <para xml:lang="en">Where <replaceable>hd0,a</replaceable> points to the
- root partition on the first disk. To specify
- the slice number, use something like this
- <replaceable>(hd0,2,a)</replaceable>. By default, if the
- slice number is omitted, <application>GRUB</application>
- searches the first slice
- which has the <literal>a</literal> partition.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="booteasy-loader">
- <para xml:lang="en">How do I boot FreeBSD and <trademark class="registered">Linux</trademark> using
- <application>BootEasy?</application></para>
- </question>
-
- <answer>
- <para xml:lang="en">Install LILO at the start of the <trademark class="registered">Linux</trademark> boot
- partition instead of in the Master Boot Record. You can
- then boot LILO from
- <application>BootEasy</application>.</para>
-
- <para xml:lang="en">This is recommended when running <trademark class="registered">Windows</trademark> and <trademark class="registered">Linux</trademark>
- as it makes it simpler to get <trademark class="registered">Linux</trademark> booting again if
- <trademark class="registered">Windows</trademark> is reinstalled.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="changing-bootprompt">
- <para xml:lang="en">How do I change the boot prompt from
- <literal>???</literal> to something more
- meaningful?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This cannot be accomplished with the standard boot
- manager without rewriting it. There are a number of other
- boot managers in the <filename>sysutils</filename>
- category of the Ports Collection.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="removable-drives">
- <para xml:lang="en">How do I use a new removable drive?</para>
- </question>
-
- <answer>
- <para xml:lang="en">If the drive already has a file system on it,
- use a command like this:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>mount -t msdosfs /dev/da0s1 /mnt</userinput></screen>
-
- <para xml:lang="en">If the drive will only be used with FreeBSD systems,
- partition it with <acronym>UFS</acronym> or
- <acronym>ZFS</acronym>. This will provide long filename
- support, improvement in performance, and stability. If
- the drive will be used by other operating systems, a more
- portable choice, such as msdosfs, is better.</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>dd if=/dev/zero of=/dev/da0 count=2</userinput>
-<prompt>#</prompt> <userinput>gpart create -s GPT /dev/da0</userinput>
-<prompt>#</prompt> <userinput>gpart add -t freebsd-ufs /dev/da0</userinput></screen>
-
- <para xml:lang="en">Finally, create a new file system:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>newfs /dev/da0p1</userinput></screen>
-
- <para xml:lang="en">and mount it:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>mount /dev/da0s1 /mnt</userinput></screen>
-
- <para xml:lang="en">It is a good idea to add a line to
- <filename>/etc/fstab</filename> (see <citerefentry><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>) so you
- can just type <command>mount /mnt</command> in the
- future:</para>
-
- <programlisting xml:lang="en">/dev/da0p1 /mnt ufs rw,noauto 0 0</programlisting>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="mount-cd-superblock">
- <para xml:lang="en">Why do I get <errorname>Incorrect super
- block</errorname> when mounting a CD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The type of device to mount must be specified. This
- is described in the Handbook section on <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/creating-cds.html#mounting-cd">Using
- Data CDs</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="cdrom-not-configured">
- <para xml:lang="en">Why do I get <errorname>Device not
- configured</errorname> when mounting a CD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This generally means that there is no CD in the
- drive, or the drive is not visible on the bus.
- Refer to the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/creating-cds.html#mounting-cd">Using
- Data CDs</link> section of the Handbook for a detailed
- discussion of this issue.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="cdrom-unicode-filenames">
- <para xml:lang="en">Why do all non-English characters in filenames show up
- as <quote>?</quote> on my CDs when mounted in FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The CD probably uses the <quote>Joliet</quote>
- extension for storing information about files and
- directories. This is discussed in the Handbook section on
- <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/creating-cds.html#mounting-cd">Using
- Data CD-ROMs</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="burncd-isofs">
- <para xml:lang="en">A CD burned under FreeBSD cannot be read
- under any other operating system. Why?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This means a raw file was burned to the CD, rather
- than creating an ISO 9660 file system. Take a look
- at the Handbook section on <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/creating-cds.html#mounting-cd">Using
- Data <acronym>CD</acronym>s</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="copy-cd">
- <para xml:lang="en">How can I create an image of a data CD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This is discussed in the Handbook section on <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/creating-cds.html#mkisofs">Writing
- Data to an <acronym>ISO</acronym> File System</link>.
- For more on working with CD-ROMs, see the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/creating-cds.html">Creating
- CDs Section</link> in the Storage chapter in the
- Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="mount-audio-CD">
- <para xml:lang="en">Why can I not <command>mount</command> an audio
- CD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Trying to mount an audio CD will produce an error
- like <errorname>cd9660: /dev/cd0: Invalid
- argument</errorname>. This is because
- <command>mount</command> only works on file systems.
- Audio CDs do not have file systems; they just have data.
- Instead, use a program that reads audio CDs, such as the
- <package>audio/xmcd</package> package or port.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="multi-session-CD">
- <para xml:lang="en">How do I <command>mount</command> a multi-session
- CD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">By default, <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry> will attempt to mount the
- last data track (session) of a CD. To
- load an earlier session, use the
- <option>-s</option> command line argument. Refer to
- <citerefentry><refentrytitle>mount_cd9660</refentrytitle><manvolnum>8</manvolnum></citerefentry> for specific examples.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="user-floppymount">
- <para xml:lang="en">How do I let ordinary users mount CD-ROMs, DVDs,
- USB drives, and other removable media?</para>
- </question>
-
- <answer>
- <para xml:lang="en">As <systemitem class="username">root</systemitem> set
- the sysctl variable <varname>vfs.usermount</varname> to
- <literal>1</literal>.</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>sysctl vfs.usermount=1</userinput></screen>
-
- <para xml:lang="en">To make this persist across reboots, add the line
- <literal>vfs.usermount=1</literal> to
- <filename>/etc/sysctl.conf</filename> so that it is reset
- at system boot time.</para>
-
- <para xml:lang="en">Users can only mount devices they have read
- permissions to. To allow users to mount a device
- permissions must be set in
- <filename>/etc/devfs.conf</filename>.</para>
-
- <para xml:lang="en">For example, to allow users to mount the first USB
- drive add:</para>
-
- <programlisting xml:lang="en"># Allow all users to mount a USB drive.
- own /dev/da0 root:operator
- perm /dev/da0 0666</programlisting>
-
- <para xml:lang="en">All users can now mount devices they could read onto a
- directory that they own:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>mkdir ~/my-mount-point</userinput>
-<prompt>%</prompt> <userinput>mount -t msdosfs /dev/da0 ~/my-mount-point</userinput></screen>
-
- <para xml:lang="en">Unmounting the device is simple:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>umount ~/my-mount-point</userinput></screen>
-
- <para xml:lang="en">Enabling <varname>vfs.usermount</varname>, however,
- has negative security implications. A better way to
- access <trademark class="registered">MS-DOS</trademark> formatted media is to use the
- <package>emulators/mtools</package> package in the Ports
- Collection.</para>
-
- <note>
- <para xml:lang="en">The device name used in the previous examples must
- be changed according to the configuration.</para>
- </note>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="du-vs-df">
- <para xml:lang="en">The <command>du</command> and <command>df</command>
- commands show different amounts of disk space available.
- What is going on?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This is due to how these commands actually work.
- <command>du</command> goes through the directory tree,
- measures how large each file is, and presents the totals.
- <command>df</command> just asks the file system how much
- space it has left. They seem to be the same thing, but a
- file without a directory entry will affect
- <command>df</command> but not
- <command>du</command>.</para>
-
- <para xml:lang="en">When a program is using a file, and the file is
- deleted, the file is not really removed from the file
- system until the program stops using it. The file is
- immediately deleted from the directory listing, however.
- As an example, consider a file large enough
- to affect the output of
- <command>du</command> and <command>df</command>. A
- file being viewed with <command>more</command> can be
- deleted wihout causing an error.
- The entry is
- removed from the directory so no other program or user can
- access it. However, <command>du</command> shows that it
- is gone as it has walked the directory tree and the
- file is not listed. <command>df</command> shows that it
- is still there, as the file system knows that
- <command>more</command> is still using that space. Once
- the <command>more</command> session ends,
- <command>du</command> and <command>df</command> will
- agree.</para>
-
- <para xml:lang="en">This situation is common on web servers. Many people
- set up a FreeBSD web server and forget to rotate the log
- files. The access log fills up <filename>/var</filename>.
- The new administrator deletes the file, but the system
- still complains that the partition is full. Stopping and
- restarting the web server program would free the file,
- allowing the system to release the disk space. To prevent
- this from happening, set up <citerefentry><refentrytitle>newsyslog</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
-
- <para xml:lang="en">Note that Soft Updates can delay the freeing of disk
- space and it can take up to 30 seconds for the
- change to be visible.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="add-swap-space">
- <para xml:lang="en">How can I add more swap space?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This section <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/adding-swap-space.html">of
- the Handbook</link> describes how to do this.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="manufacturer-disk-size">
- <para xml:lang="en">Why does FreeBSD see my disk as smaller than the
- manufacturer says it is?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Disk manufacturers calculate gigabytes as a billion
- bytes each, whereas FreeBSD calculates them as
- 1,073,741,824 bytes each. This explains why, for
- example, FreeBSD's boot messages will report a disk that
- supposedly has 80 GB as holding
- 76,319 MB.</para>
-
- <para xml:lang="en">Also note that FreeBSD will (by default) <link linkend="disk-more-than-full">reserve</link> 8% of the
- disk space.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="disk-more-than-full">
- <para xml:lang="en">How is it possible for a partition to be more than
- 100% full?</para>
- </question>
-
- <answer>
- <para xml:lang="en">A portion of each UFS partition (8%, by default) is
- reserved for use by the operating system and the
- <systemitem class="username">root</systemitem> user.
- <citerefentry><refentrytitle>df</refentrytitle><manvolnum>1</manvolnum></citerefentry> does not count that space when calculating the
- <literal>Capacity</literal> column, so it can exceed 100%.
- Notice that the <literal>Blocks</literal>
- column is always greater than the sum of the
- <literal>Used</literal> and <literal>Avail</literal>
- columns, usually by a factor of 8%.</para>
-
- <para xml:lang="en">For more details, look up <option>-m</option> in
- <citerefentry><refentrytitle>tunefs</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
- </answer>
- </qandaentry>
-
- </qandaset>
- </chapter>
-
- <chapter xml:id="all-about-zfs">
- <title xml:lang="en">ZFS</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="how-much-ram-for-zfs">
- <para>使用 ZFS 最少需要多少記憶體?</para>
- </question>
-
- <answer>
- <para>至少需要 4GB 的記憶體才能跑得順,但不同的工作負載可能會造成相當大的差異。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="what-is-zil">
- <para>ZIL 是什麼而又何時會被使用?</para>
- </question>
-
- <answer>
- <para>The <acronym>ZIL</acronym> (<acronym>ZFS</acronym> 動向日誌) 是一個紀錄日誌,用以實現系統當機時 POSIX 寫入保證的語義,多個正常 ZFS 寫入動作會被分成多個交易處理群組,並在交易處理群組被填滿時寫入磁碟 (<quote>Transaction Group Commit</quote>)。然而像 <citerefentry><refentrytitle>fsync</refentrytitle><manvolnum>2</manvolnum></citerefentry> 這樣的系統呼叫,會要求該系統呼叫在返回前,能承諾已將資料寫入磁碟,ZIL 就是用來紀錄確認為已執行寫入的資料,但其實尚未存在於磁碟上,即尚未完成交易處理,交易處理群組具有時間戳記,在系統當機後,找到 ZIL 最後一個有效的時間戳記,即將遺失的資料再舍併至磁碟上。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="need-ssd-for-zil">
- <para>我需要用固態硬碟 (SSD) 來存 ZIL 嗎?</para>
- </question>
-
- <answer>
- <para>ZFS 預設將 ZIL 儲存在包含所有資料的 zpool 中,如果應用程式的寫入負載很重,將 ZIL 儲存在同步速度非常快的獨立設備中,藉由循序寫入效能的提高可以改善整個系統的效能,對於其他類型的工作負載, 固態硬碟就不會有太大的助益。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="what-is-l2arc">
- <para>L2ARC 是什麼?</para>
- </question>
-
- <answer>
- <para>The <acronym>L2ARC</acronym> (Second Level Adaptive Replacement Cache) 是存於快速儲存設備 <acronym>SSD</acronym> 上的讀取快取,此快取在重新開機後會消失,請注意記憶體是第一層的快取,只有在記憶體不足的情況下才需要 L2ARC。</para>
-
- <para>L2ARC 需要 ARC 的空間來為其製作索引,因此,有一種反常的情況,如果有一種工作集 (working set) 可以完美地剛好放入 ARC,一旦系統使用 L2ARC,該工作集的運作將不再完美,因為 ARC 需要用一部分空間來保存 L2ARC 的索引,以至於必須將工作集的一部分存入比記憶體慢的 L2ARC。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="should-enable-dedup">
- <para>建議啟用去冗餘 (deduplication) 嗎?</para>
- </question>
-
- <answer>
- <para>一般而言,不建議這麼做。</para>
-
- <para>去冗餘需要相當多的記憶體,而且會讓讀寫磁碟所需的時間變長,除非磁碟上儲存了非常多重複的資料,例如:虛擬機的映像檔或者是使用者的備份資料,否則開啟去冗餘可能弊大於利。另一個需要考量的狀況是:啟用去冗餘功能之後再將其關閉,無法將磁碟上去冗餘的狀態立即逆轉,必須等到下次修改了之前被去冗餘的資料,變更的區塊才會再被複製一份。</para>
-
- <para>去冗餘也可能會導致某些非預期的情況,特別是刪除檔案時可能會慢很多。</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="zpool-fully-full">
- <para>在我建立的 ZFS pool 中無法刪除和新增檔案,應該怎麼修復?</para>
- </question>
-
- <answer>
- <para>這很有可能是該 pool 的空間使用率已達 100% 滿了,因 ZFS 需要儲存空間以將紀錄交易處理的輔助資料 (metadata) 寫入,為了讓該 pool 回復至可用狀態,必須用檔案切除的方法 (truncate 命令) 刪除不重要的檔案:</para>
-
- <screen><prompt>%</prompt> <userinput>truncate -s 0 unimportant-file</userinput></screen>
-
- <para>因為檔案切除不需要建立交易處理紀錄,並能釋放出可使用的磁碟區塊。</para>
-
- <note>
- <para>如果系統曾進行過額外的 ZFS dataset 調校,例如:去冗餘,釋放出來的空間也許不會立即可得。</para>
- </note>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="zfs-ssd-trim">
- <para>ZFS 支援固態硬碟 (SSD) 的 TRIM 功能嗎?</para>
- </question>
-
- <answer>
- <para>自 FreeBSD 10-CURRENT 修定 r<revnumber>240868</revnumber> 開始,就支援 ZFS TRIM。ZFS TRIM 的支援分別已在 r<revnumber>252162</revnumber> 和 r<revnumber>251419</revnumber> 的修訂,加進所有 FreeBSD-STABLE 分支。</para>
-
- <para>ZFS TRIM 預設就已開啟,也可以將其關閉,只要加入一行設定到 <filename>/etc/sysctl.conf</filename>:</para>
-
- <programlisting>vfs.zfs.trim.enabled=0</programlisting>
-
- <note>
- <para>ZFS TRIM 也可能某些設定中會無效,例如:在採用 GELI 裝置上的 ZFS 檔案系統。</para>
- </note>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="admin">
- <title xml:lang="en">System Administration</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="startup-config-files">
- <para xml:lang="en">Where are the system start-up configuration
- files?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The primary configuration file is
- <filename>/etc/defaults/rc.conf</filename> which is
- described in <citerefentry><refentrytitle>rc.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. System startup scripts
- such as <filename>/etc/rc</filename> and
- <filename>/etc/rc.d</filename>, which are described in
- <citerefentry><refentrytitle>rc</refentrytitle><manvolnum>8</manvolnum></citerefentry>, include this file. <emphasis>Do not edit this
- file!</emphasis> Instead, to edit an entry in
- <filename>/etc/defaults/rc.conf</filename>, copy the line
- into <filename>/etc/rc.conf</filename> and change it
- there.</para>
-
- <para xml:lang="en">For example, if to start <citerefentry><refentrytitle>named</refentrytitle><manvolnum>8</manvolnum></citerefentry>, the
- included DNS server:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>echo 'named_enable="YES"' &gt;&gt; /etc/rc.conf</userinput></screen>
-
- <para xml:lang="en">To start up local services, place shell scripts in the
- <filename>/usr/local/etc/rc.d</filename> directory. These
- shell scripts should be set executable, the default file
- mode is <literal>555</literal>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="adding-users">
- <para xml:lang="en">How do I add a user easily?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Use the <citerefentry><refentrytitle>adduser</refentrytitle><manvolnum>8</manvolnum></citerefentry> command, or the <citerefentry><refentrytitle>pw</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- command for more complicated situations.</para>
-
- <para xml:lang="en">To remove the user, use the <citerefentry><refentrytitle>rmuser</refentrytitle><manvolnum>8</manvolnum></citerefentry> command or,
- if necessary, <citerefentry><refentrytitle>pw</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="root-not-found-cron-errors">
- <para xml:lang="en">Why do I keep getting messages like <errorname>root:
- not found</errorname> after editing
- <filename>/etc/crontab</filename>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This is normally caused by editing the system crontab.
- This is not the correct way to do things as the system
- crontab has a different format to the per-user crontabs.
- The system
- crontab has an extra field, specifying which user to run
- the command as. <citerefentry><refentrytitle>cron</refentrytitle><manvolnum>8</manvolnum></citerefentry> assumes this user is the
- first word of the command to execute. Since no such
- command exists, this error message is displayed.</para>
-
- <para xml:lang="en">To delete the extra, incorrect crontab:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>crontab -r</userinput></screen>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="su-wheel-group">
- <para xml:lang="en">Why do I get the error, <errorname>you are not in the
- correct group to su root</errorname> when I try to
- <command>su</command> to <systemitem class="username">root</systemitem>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This is a security feature. In order to
- <command>su</command> to
- <systemitem class="username">root</systemitem>, or any
- other account with superuser privileges, the user account
- must be a member of the
- <systemitem class="groupname">wheel</systemitem> group.
- If this feature were not there, anybody with an
- account on a system who also found out <systemitem class="username">root</systemitem>'s password would be
- able to gain superuser level access to the system.</para>
-
- <para xml:lang="en">To allow someone to <command>su</command> to
- <systemitem class="username">root</systemitem>, put
- them in the <systemitem class="groupname">wheel</systemitem> group using
- <command>pw</command>:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>pw groupmod wheel -m lisa</userinput></screen>
-
- <para xml:lang="en">The above example will add user <systemitem class="username">lisa</systemitem> to the group
- <systemitem class="groupname">wheel</systemitem>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="rcconf-readonly">
- <para xml:lang="en">I made a mistake in <filename>rc.conf</filename>, or
- another startup file, and now I cannot edit it because the
- file system is read-only. What should I do?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Restart the system using <userinput>boot
- -s</userinput> at the loader prompt to enter single-user
- mode. When prompted for a shell pathname, press
- <keycap>Enter</keycap> and run <command>mount -urw
- /</command> to re-mount the root file system in
- read/write mode. You may also need to run <command>mount
- -a -t ufs</command> to mount the file system where your
- favorite editor is defined. If that editor is on a
- network file system, either configure the network manually
- before mounting the network file systems, or use an editor
- which resides on a local file system, such as
- <citerefentry><refentrytitle>ed</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
-
- <para xml:lang="en">In order to use a full screen editor such as
- <citerefentry><refentrytitle>vi</refentrytitle><manvolnum>1</manvolnum></citerefentry> or <citerefentry vendor="ports"><refentrytitle>emacs</refentrytitle><manvolnum>1</manvolnum></citerefentry>, run
- <command>export TERM=xterm</command>
- so that these editors can load the correct data from the
- <citerefentry><refentrytitle>termcap</refentrytitle><manvolnum>5</manvolnum></citerefentry> database.</para>
-
- <para xml:lang="en">After performing these steps, edit
- <filename>/etc/rc.conf</filename> to
- fix the syntax error. The error message displayed
- immediately after the kernel boot messages should indicate
- the number of the line in the file which is at
- fault.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="printer-setup">
- <para xml:lang="en">Why am I having trouble setting up my printer?</para>
- </question>
-
- <answer>
- <para xml:lang="en">See the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/printing.html">Handbook
- entry on printing</link> for troubleshooting
- tips.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="keyboard-mappings">
- <para xml:lang="en">How can I correct the keyboard mappings for my
- system?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Refer to the Handbook section on <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/using-localization.html">using
- localization</link>, specifically the section on <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/using-localization.html#setting-console">console
- setup</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="user-quotas">
- <para xml:lang="en">Why can I not get user quotas to work properly?</para>
- </question>
-
- <answer>
- <orderedlist>
- <listitem>
- <para xml:lang="en">It is possible that the kernel is not configured
- to use quotas. In this case,
- add the following line to the kernel configuration
- file and recompile the kernel:</para>
-
- <programlisting xml:lang="en">options QUOTA</programlisting>
-
- <para xml:lang="en">Refer to the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/quotas.html">Handbook
- entry on quotas</link> for full details.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Do not turn on quotas on
- <filename>/</filename>.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Put the quota file on the file system that the
- quotas are to be enforced on:</para>
-
- <informaltable frame="none" pgwide="1">
- <tgroup cols="2">
- <thead>
- <row>
- <entry xml:lang="en">File System</entry>
-
- <entry xml:lang="en">Quota file</entry>
- </row>
- </thead>
-
- <tbody>
- <row>
- <entry xml:lang="en"><filename>/usr</filename></entry>
-
- <entry xml:lang="en"><filename>/usr/admin/quotas</filename></entry>
- </row>
-
- <row>
- <entry xml:lang="en"><filename>/home</filename></entry>
-
- <entry xml:lang="en"><filename>/home/admin/quotas</filename></entry>
- </row>
-
- <row>
- <entry xml:lang="en">…</entry>
-
- <entry xml:lang="en">…</entry>
- </row>
- </tbody>
- </tgroup>
- </informaltable>
- </listitem>
- </orderedlist>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="sysv-ipc">
- <para xml:lang="en">Does FreeBSD support System V IPC primitives?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes, FreeBSD supports System V-style IPC, including
- shared memory, messages and semaphores, in the
- <filename>GENERIC</filename> kernel. With a custom
- kernel, support may be loaded with the
- <filename>sysvshm.ko</filename>,
- <filename>sysvsem.ko</filename> and
- <filename>sysvmsg.ko</filename> kernel modules, or
- enabled in the custom kernel by adding the following lines
- to the kernel configuration file:</para>
-
- <programlisting xml:lang="en">options SYSVSHM # enable shared memory
-options SYSVSEM # enable for semaphores
-options SYSVMSG # enable for messaging</programlisting>
-
- <para xml:lang="en">Recompile and install the kernel.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="sendmail-alternative">
- <para xml:lang="en">What other mail-server software can I use instead of
- <application>Sendmail</application>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The <link xlink:href="http://www.sendmail.org/"><application>Sendmail</application></link>
- server is the default mail-server software for FreeBSD, but
- it can be replaced with another
- MTA installed from the Ports Collection. Available ports
- include <package>mail/exim</package>,
- <package>mail/postfix</package>, and
- <package>mail/qmail</package>. Search the mailing lists
- for discussions regarding the advantages and disadvantages
- of the available MTAs.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="forgot-root-pw">
- <para xml:lang="en">I have forgotten the <systemitem class="username">root</systemitem> password! What do I
- do?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Do not panic! Restart the system, type
- <userinput>boot -s</userinput> at the
- <literal>Boot:</literal> prompt to enter single-user mode.
- At the question about the shell to use, hit
- <keycap>Enter</keycap> which will display a
- <prompt>#</prompt> prompt. Enter <command>mount
- -urw /</command> to remount the root file system
- read/write, then run <command>mount -a</command> to
- remount all the file systems. Run <command>passwd
- root</command> to change the <systemitem class="username">root</systemitem> password then run
- <citerefentry><refentrytitle>exit</refentrytitle><manvolnum>1</manvolnum></citerefentry> to continue booting.</para>
-
- <note>
- <para xml:lang="en">If you are still prompted to give the <systemitem class="username">root</systemitem> password when
- entering the single-user mode, it means that the console
- has been marked as <literal>insecure</literal> in
- <filename>/etc/ttys</filename>. In this case, it will
- be required to boot from a FreeBSD installation disk,
- choose the <guimenuitem>Live CD</guimenuitem> or
- <guimenuitem>Shell</guimenuitem> at the beginning of the
- install process and issue the commands mentioned above.
- Mount the specific partition in this
- case and then chroot to it. For example, replace
- <command>mount -urw /</command> with
- <command>mount /dev/ada0p1 /mnt; chroot /mnt</command>
- for a system on
- <replaceable>ada0p1</replaceable>.</para>
- </note>
-
- <note>
- <para xml:lang="en">If the root partition cannot be mounted from
- single-user mode, it is possible that the partitions are
- encrypted and it is impossible to mount them without the
- access keys. For more information see the section
- about encrypted disks in the FreeBSD <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/disks-encrypting.html">Handbook</link>.</para>
- </note>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="CAD-reboot">
- <para xml:lang="en">How do I keep <keycombo action="simul"><keycap>Control</keycap><keycap>Alt</keycap><keycap>Delete</keycap></keycombo>
- from rebooting the system?</para>
- </question>
-
- <answer>
- <para xml:lang="en">When using <citerefentry><refentrytitle>syscons</refentrytitle><manvolnum>4</manvolnum></citerefentry>, the default console
- driver, build and install a new kernel with this line in
- the configuration file:</para>
-
- <programlisting xml:lang="en">options SC_DISABLE_REBOOT</programlisting>
-
- <para xml:lang="en">This can also be done by setting the following
- <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry> which does not require a reboot or kernel
- recompile:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>sysctl hw.syscons.kbd_reboot=0</userinput></screen>
-
- <note>
- <para xml:lang="en">The above two methods are exclusive: The
- <citerefentry><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry> does not exist if the kernel is compiled
- with <literal>SC_DISABLE_REBOOT</literal>.</para>
- </note>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="dos-to-unix-txt">
- <para xml:lang="en">How do I reformat DOS text files to <trademark class="registered">UNIX</trademark>
- ones?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Use this <citerefentry><refentrytitle>perl</refentrytitle><manvolnum>1</manvolnum></citerefentry> command:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>perl -i.bak -npe 's/\r\n/\n/g' file(s)</userinput></screen>
-
- <para xml:lang="en">where <replaceable>file(s)</replaceable> is one or
- more files to process. The modification is done in-place,
- with the original file stored with a
- <filename>.bak</filename> extension.</para>
-
- <para xml:lang="en">Alternatively, use <citerefentry><refentrytitle>tr</refentrytitle><manvolnum>1</manvolnum></citerefentry>:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>tr -d '\r' &lt; dos-text-file &gt; unix-file</userinput></screen>
-
- <para xml:lang="en"><replaceable>dos-text-file</replaceable> is the file
- containing DOS text while
- <replaceable>unix-file</replaceable> will contain the
- converted output. This can be quite a bit faster than
- using <command>perl</command>.</para>
-
- <para xml:lang="en">Yet another way to reformat DOS text files is to use
- the <package>converters/dosunix</package> port from the
- Ports Collection. Consult its documentation about the
- details.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="reread-rc">
- <para xml:lang="en">How do I re-read <filename>/etc/rc.conf</filename> and
- re-start <filename>/etc/rc</filename> without a
- reboot?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Go into single-user mode and then back to multi-user
- mode:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>shutdown now</userinput>
-<prompt>#</prompt> <userinput>return</userinput>
-<prompt>#</prompt> <userinput>exit</userinput></screen>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="release-candidate">
- <para xml:lang="en">I tried to update my system to the latest
- <emphasis>-STABLE</emphasis>, but got
- <emphasis>-BETA<replaceable>x</replaceable></emphasis>,
- <emphasis>-RC</emphasis> or
- <emphasis>-PRERELEASE</emphasis>! What is going
- on?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Short answer: it is just a name.
- <emphasis>RC</emphasis> stands for <quote>Release
- Candidate</quote>. It signifies that a release is
- imminent. In FreeBSD, <emphasis>-PRERELEASE</emphasis> is
- typically synonymous with the code freeze before a
- release. (For some releases, the
- <emphasis>-BETA</emphasis> label was used in the same way
- as <emphasis>-PRERELEASE</emphasis>.)</para>
-
- <para xml:lang="en">Long answer: FreeBSD derives its releases from one of two
- places. Major, dot-zero, releases, such as 9.0-RELEASE
- are branched from the head of the development stream,
- commonly referred to as <link linkend="current">-CURRENT</link>. Minor releases, such
- as 6.3-RELEASE or 5.2-RELEASE, have been snapshots of the
- active <link linkend="stable">-STABLE</link> branch.
- Starting with 4.3-RELEASE, each release also now has its
- own branch which can be tracked by people requiring an
- extremely conservative rate of development (typically only
- security advisories).</para>
-
- <para xml:lang="en">When a release is about to be made, the branch from
- which it will be derived from has to undergo a certain
- process. Part of this process is a code freeze. When a
- code freeze is initiated, the name of the branch is
- changed to reflect that it is about to become a release.
- For example, if the branch used to be called 6.2-STABLE,
- its name will be changed to 6.3-PRERELEASE to signify the
- code freeze and signify that extra pre-release testing
- should be happening. Bug fixes can still be committed to
- be part of the release. When the source code is in shape
- for the release the name will be changed to 6.3-RC to
- signify that a release is about to be made from it. Once
- in the RC stage, only the most critical bugs found can be
- fixed. Once the release (6.3-RELEASE in this example) and
- release branch have been made, the branch will be renamed
- to 6.3-STABLE.</para>
-
- <para xml:lang="en">For more information on version numbers and the
- various Subversion branches, refer to the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/articles/releng/article.html">Release
- Engineering</link> article.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="kernel-chflag-failure">
- <para xml:lang="en">I tried to install a new kernel, and the
- <citerefentry><refentrytitle>chflags</refentrytitle><manvolnum>1</manvolnum></citerefentry> failed. How do I get around this?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Short answer: the security level is
- greater than 0. Reboot directly to single-user mode to
- install the kernel.</para>
-
- <para xml:lang="en">Long answer: FreeBSD disallows changing system flags at
- security levels greater than 0. To check the current
- security level:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>sysctl kern.securelevel</userinput></screen>
-
- <para xml:lang="en">The security level cannot be lowered in multi-user
- mode, so boot to single-user mode to install the kernel,
- or change the security level in
- <filename>/etc/rc.conf</filename> then reboot. See the
- <citerefentry><refentrytitle>init</refentrytitle><manvolnum>8</manvolnum></citerefentry> manual page for details on
- <literal>securelevel</literal>, and see
- <filename>/etc/defaults/rc.conf</filename> and the
- <citerefentry><refentrytitle>rc.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> manual page for more information on
- <filename>rc.conf</filename>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="kernel-securelevel-time">
- <para xml:lang="en">I cannot change the time on my system by more than one
- second! How do I get around this?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Short answer: the system is at a security level
- greater than 1. Reboot directly to single-user mode to
- change the date.</para>
-
- <para xml:lang="en">Long answer: FreeBSD disallows changing the time by more
- that one second at security levels greater than 1. To
- check the security level:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>sysctl kern.securelevel</userinput></screen>
-
- <para xml:lang="en">The security level cannot be lowered in multi-user
- mode. Either boot to single-user mode to change the date
- or change the security level in
- <filename>/etc/rc.conf</filename> and reboot. See the
- <citerefentry><refentrytitle>init</refentrytitle><manvolnum>8</manvolnum></citerefentry> manual page for details on
- <literal>securelevel</literal>, and see
- <filename>/etc/defaults/rc.conf</filename> and the
- <citerefentry><refentrytitle>rc.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> manual page for more information on
- <filename>rc.conf</filename>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="statd-mem-leak">
- <para xml:lang="en">Why is <command>rpc.statd</command> using 256 MB
- of memory?</para>
- </question>
-
- <answer>
- <para xml:lang="en">No, there is no memory leak, and it is not using
- 256 MB of memory. For convenience,
- <command>rpc.statd</command> maps an obscene amount of
- memory into its address space. There is nothing terribly
- wrong with this from a technical standpoint; it just
- throws off things like <citerefentry><refentrytitle>top</refentrytitle><manvolnum>1</manvolnum></citerefentry> and <citerefentry><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
-
- <para xml:lang="en"><citerefentry><refentrytitle>rpc.statd</refentrytitle><manvolnum>8</manvolnum></citerefentry> maps its status file (resident on
- <filename>/var</filename>) into its address space; to save
- worrying about remapping the status file later when it
- needs to grow, it maps the status file with a generous
- size. This is very evident from the source code, where
- one can see that the length argument to <citerefentry><refentrytitle>mmap</refentrytitle><manvolnum>2</manvolnum></citerefentry> is
- <literal>0x10000000</literal>, or one sixteenth of the
- address space on an IA32, or exactly 256 MB.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="unsetting-schg">
- <para xml:lang="en">Why can I not unset the <literal>schg</literal> file
- flag?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The system is running at securelevel greater than 0.
- Lower the securelevel and try again. For more
- information, see <link linkend="securelevel">the
- <acronym>FAQ</acronym> entry on securelevel</link> and
- the <citerefentry><refentrytitle>init</refentrytitle><manvolnum>8</manvolnum></citerefentry> manual page.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="vnlru">
- <para xml:lang="en">What is <literal>vnlru</literal>?</para>
- </question>
-
- <answer>
- <para xml:lang="en"><literal>vnlru</literal> flushes and frees vnodes when
- the system hits the <varname>kern.maxvnodes</varname>
- limit. This kernel thread sits mostly idle, and only
- activates when there is a huge amount of RAM and users are
- accessing tens of thousands of tiny files.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="top-memory-states">
- <para xml:lang="en">What do the various memory states displayed by
- <command>top</command> mean?</para>
- </question>
-
- <!-- Provided by John Dyson via Usenet -->
- <answer>
- <itemizedlist>
- <listitem>
- <para xml:lang="en"><literal>Active</literal>: pages recently
- statistically used.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en"><literal>Inactive</literal>: pages recently
- statistically unused.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en"><literal>Cache</literal>: (most often) pages that
- have percolated from inactive to a status where they
- maintain their data, but can often be immediately
- reused (either with their old association, or reused
- with a new association). There can be certain
- immediate transitions from <literal>active</literal>
- to <literal>cache</literal> state if the page is known
- to be clean (unmodified), but that transition is a
- matter of policy, depending upon the algorithm choice
- of the VM system maintainer.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en"><literal>Free</literal>: pages without data
- content, and can be immediately used in certain
- circumstances where cache pages might be ineligible.
- Free pages can be reused at interrupt or process
- state.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en"><literal>Wired</literal>: pages that are fixed
- into memory, usually for kernel purposes, but also
- sometimes for special use in processes.</para>
- </listitem>
- </itemizedlist>
-
- <para xml:lang="en">Pages are most often written to disk (sort of a VM
- sync) when they are in the inactive state, but active
- pages can also be synced. This depends upon the CPU
- tracking of the modified bit being available, and in
- certain situations there can be an advantage for a block
- of VM pages to be synced, whether they are active or
- inactive. In most common cases, it is best to think of
- the inactive queue to be a queue of relatively unused
- pages that might or might not be in the process of being
- written to disk. Cached pages are already synced, not
- mapped, but available for immediate process use with their
- old association or with a new association. Free pages are
- available at interrupt level, but cached or free pages can
- be used at process state for reuse. Cache pages are not
- adequately locked to be available at interrupt
- level.</para>
-
- <para xml:lang="en">There are some other flags (e.g., busy flag or busy
- count) that might modify some of the described
- rules.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="free-memory-amount">
- <para xml:lang="en">How much free memory is available?</para>
- </question>
-
- <!-- Provided by John Dyson via Usenet -->
- <answer>
- <para xml:lang="en">There are a couple of kinds of <quote>free
- memory</quote>. One kind is the amount of memory
- immediately available without paging anything else out.
- That is approximately the size of cache queue + size of
- free queue (with a derating factor, depending upon system
- tuning). Another kind of <quote>free memory</quote> is
- the total amount of <acronym>VM</acronym> space. That can
- be complex, but is dependent upon the amount of swap space
- and memory. Other kinds of <quote>free memory</quote>
- descriptions are also possible, but it is relatively
- useless to define these, but rather it is important to
- make sure that the paging rate is kept low, and to avoid
- running out of swap space.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="var-empty">
- <para xml:lang="en">What is <filename>/var/empty</filename>?</para>
- </question>
-
- <answer>
- <para xml:lang="en"><filename>/var/empty</filename> is a directory that
- the <citerefentry><refentrytitle>sshd</refentrytitle><manvolnum>8</manvolnum></citerefentry> program uses when performing privilege
- separation. The <filename>/var/empty</filename>
- directory is empty, owned by <systemitem class="username">root</systemitem> and has the
- <literal>schg</literal> flag set. This directory should
- not be deleted.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="newsyslog-expectations">
- <para xml:lang="en">I just changed
- <filename>/etc/newsyslog.conf</filename>. How can I check
- if it does what I expect?</para>
- </question>
-
- <answer>
- <para xml:lang="en">To see what <citerefentry><refentrytitle>newsyslog</refentrytitle><manvolnum>8</manvolnum></citerefentry> will do, use the
- following:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>newsyslog -nrvv</userinput></screen>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="timezone">
- <para xml:lang="en">My time is wrong, how can I change the
- timezone?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Use <citerefentry><refentrytitle>tzsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="x">
- <title xml:lang="en">The X Window System and Virtual Consoles</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="whatis-X">
- <para xml:lang="en">What is the X Window System?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The X Window System (commonly <literal>X11</literal>)
- is the most widely available windowing system capable of
- running on <trademark class="registered">UNIX</trademark> or <trademark class="registered">UNIX</trademark> like systems, including
- FreeBSD. <link xlink:href="http://www.x.org/wiki/">The X.Org
- Foundation</link> administers the <link xlink:href="http://en.wikipedia.org/wiki/X_Window_System_core_protocol">X
- protocol standards</link>, with the current reference
- implementation, version 11 release 7.7, so
- references are often shortened to
- <literal>X11</literal>.</para>
-
- <para xml:lang="en">Many implementations are available for different
- architectures and operating systems. An implementation of
- the server-side code is properly known as an <literal>X
- server</literal>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="running-X">
- <para xml:lang="en">I want to run Xorg, how do I go about it?</para>
- </question>
-
- <answer>
- <para xml:lang="en">To install Xorg do one of the following:</para>
-
- <para xml:lang="en">Use the <package>x11/xorg</package>
- meta-port, which builds and installs every Xorg
- component.</para>
-
- <para xml:lang="en">Use <package>x11/xorg-minimal</package>, which builds
- and installs only the necessary Xorg components.</para>
-
- <para xml:lang="en">Install Xorg from FreeBSD packages:</para>
-
- <screen xml:lang="en"><userinput><prompt>#</prompt> pkg install xorg</userinput></screen>
-
- <para xml:lang="en">After the installation of Xorg, follow the
- instructions from the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/x-config.html">X11
- Configuration</link> section of the FreeBSD
- Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="running-X-securelevels">
- <para xml:lang="en">I <emphasis>tried</emphasis> to run X, but I get a
- <errorname>No devices detected.</errorname> error when I
- type <command>startx</command>. What do I do now?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The system is probably running at a raised
- <literal>securelevel</literal>. It is not possible to
- start X at a raised <literal>securelevel</literal> because
- X requires write access to <citerefentry><refentrytitle>io</refentrytitle><manvolnum>4</manvolnum></citerefentry>. For more
- information, see at the <citerefentry><refentrytitle>init</refentrytitle><manvolnum>8</manvolnum></citerefentry> manual page.</para>
-
- <para xml:lang="en">There are two solutions to the problem: set the
- <literal>securelevel</literal> back down to zero or run
- <citerefentry vendor="xfree86"><refentrytitle>xdm</refentrytitle><manvolnum>1</manvolnum></citerefentry> (or an alternative display manager) at boot
- time before the <literal>securelevel</literal> is
- raised.</para>
-
- <para xml:lang="en">See <xref linkend="xdm-boot"/> for more information
- about running <citerefentry vendor="xfree86"><refentrytitle>xdm</refentrytitle><manvolnum>1</manvolnum></citerefentry> at boot time.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="x-and-moused">
- <para xml:lang="en">Why does my mouse not work with X?</para>
- </question>
-
- <answer>
- <para xml:lang="en">When using <citerefentry><refentrytitle>syscons</refentrytitle><manvolnum>4</manvolnum></citerefentry>, the default console
- driver, FreeBSD can be configured to support a mouse pointer
- on each virtual screen. To avoid conflicting with X,
- <citerefentry><refentrytitle>syscons</refentrytitle><manvolnum>4</manvolnum></citerefentry> supports a virtual device called
- <filename>/dev/sysmouse</filename>. All mouse events
- received from the real mouse device are written to the
- <citerefentry><refentrytitle>sysmouse</refentrytitle><manvolnum>4</manvolnum></citerefentry> device via <citerefentry><refentrytitle>moused</refentrytitle><manvolnum>8</manvolnum></citerefentry>. To use the
- mouse on one or more virtual consoles,
- <emphasis>and</emphasis> use X, see <xref linkend="moused" remap="another section"/> and set up
- <citerefentry><refentrytitle>moused</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
-
- <para xml:lang="en">Then edit <filename>/etc/X11/xorg.conf</filename> and
- make sure the following lines exist:</para>
-
- <programlisting xml:lang="en">Section "InputDevice"
- Option "Protocol" "SysMouse"
- Option "Device" "/dev/sysmouse"
-.....</programlisting>
-
- <para xml:lang="en">Starting with Xorg version 7.4, the
- <literal>InputDevice</literal> sections in
- <filename>xorg.conf</filename> are ignored in favor of
- autodetected devices. To restore the old behavior, add
- the following line to the <literal>ServerLayout</literal>
- or <literal>ServerFlags</literal> section:</para>
-
- <programlisting xml:lang="en">Option "AutoAddDevices" "false"</programlisting>
-
- <para xml:lang="en">Some people prefer to use
- <filename>/dev/mouse</filename> under X. To make this
- work, <filename>/dev/mouse</filename> should be linked
- to <filename>/dev/sysmouse</filename> (see
- <citerefentry><refentrytitle>sysmouse</refentrytitle><manvolnum>4</manvolnum></citerefentry>) by adding the following line to
- <filename>/etc/devfs.conf</filename> (see
- <citerefentry><refentrytitle>devfs.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>):</para>
-
- <programlisting xml:lang="en">link sysmouse mouse</programlisting>
-
- <para xml:lang="en">This link can be created by restarting <citerefentry vendor="current"><refentrytitle>devfs</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- with the following command (as <systemitem class="username">root</systemitem>):</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>service devfs restart</userinput></screen>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="x-and-wheel">
- <para xml:lang="en">My mouse has a fancy wheel. Can I use it in X?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes, if X is configured for a 5 button mouse. To
- do this, add the lines <literal>Buttons 5</literal>
- and <literal>ZAxisMapping 4 5</literal> to the
- <quote>InputDevice</quote> section of
- <filename>/etc/X11/xorg.conf</filename>, as seen in this
- example:</para>
-
- <programlisting xml:lang="en">Section "InputDevice"
- Identifier "Mouse1"
- Driver "mouse"
- Option "Protocol" "auto"
- Option "Device" "/dev/sysmouse"
- Option "Buttons" "5"
- Option "ZAxisMapping" "4 5"
-EndSection</programlisting>
-
- <para xml:lang="en">The mouse can be enabled in
- <application>Emacs</application>by adding these
- lines to <filename>~/.emacs</filename>:</para>
-
- <programlisting xml:lang="en">;; wheel mouse
-(global-set-key [mouse-4] 'scroll-down)
-(global-set-key [mouse-5] 'scroll-up)</programlisting>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="x-and-synaptic">
- <para xml:lang="en">My laptop has a Synaptics touchpad. Can I use it in
- X?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes, after configuring a few things to make
- it work.</para>
-
- <para xml:lang="en">In order to use the Xorg synaptics driver,
- first remove <literal>moused_enable</literal> from
- <filename>rc.conf</filename>.</para>
-
- <para xml:lang="en">To enable synaptics, add the following line to
- <filename>/boot/loader.conf</filename>:</para>
-
- <programlisting xml:lang="en">hw.psm.synaptics_support="1"</programlisting>
-
- <para xml:lang="en">Add the following to
- <filename>/etc/X11/xorg.conf</filename>:</para>
-
- <programlisting xml:lang="en">Section "InputDevice"
-Identifier "Touchpad0"
-Driver "synaptics"
-Option "Protocol" "psm"
-Option "Device" "/dev/psm0"
-EndSection</programlisting>
-
- <para xml:lang="en">And be sure to add the following into the
- <quote>ServerLayout</quote> section:</para>
-
- <programlisting xml:lang="en">InputDevice "Touchpad0" "SendCoreEvents"</programlisting>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="no-remote-x11">
- <para xml:lang="en">How do I use remote X displays?</para>
- </question>
-
- <answer>
- <para xml:lang="en">For security reasons, the default setting is to not
- allow a machine to remotely open a window.</para>
-
- <para xml:lang="en">To enable this feature, start
- <application>X</application> with the optional
- <option>-listen_tcp</option> argument:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>startx -listen_tcp</userinput></screen>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="virtual-console">
- <para xml:lang="en">What is a virtual console and how do I make
- more?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Virtual consoles provide
- several simultaneous sessions on the same machine without
- doing anything complicated like setting up a network or
- running X.</para>
-
- <para xml:lang="en">When the system starts, it will display a login prompt
- on the monitor after displaying all the boot messages.
- Type in your login name and password to
- start working on the first virtual
- console.</para>
-
- <para xml:lang="en">To start another
- session, perhaps to look at documentation for a program
- or to read mail while waiting for an
- FTP transfer to finish,
- hold down <keycap>Alt</keycap> and press
- <keycap>F2</keycap>. This will display the login prompt
- for the second virtual
- console. To go back to the
- original session, press <keycombo action="simul"><keycap>Alt</keycap><keycap>F1</keycap></keycombo>.</para>
-
- <para xml:lang="en">The default FreeBSD installation has eight virtual
- consoles enabled. <keycombo action="simul"><keycap>Alt</keycap><keycap>F1</keycap></keycombo>,
- <keycombo action="simul"><keycap>Alt</keycap><keycap>F2</keycap></keycombo>,
- <keycombo action="simul"><keycap>Alt</keycap><keycap>F3</keycap></keycombo>,
- and so on will switch between these virtual
- consoles.</para>
-
- <para xml:lang="en">To enable more of virtual consoles, edit
- <filename>/etc/ttys</filename> (see <citerefentry><refentrytitle>ttys</refentrytitle><manvolnum>5</manvolnum></citerefentry>) and add
- entries for <filename>ttyv8</filename> to
- <filename>ttyvc</filename>, after the comment on
- <quote>Virtual terminals</quote>:</para>
-
- <programlisting xml:lang="en"># Edit the existing entry for ttyv8 in /etc/ttys and change
-# "off" to "on".
-ttyv8 "/usr/libexec/getty Pc" xterm on secure
-ttyv9 "/usr/libexec/getty Pc" xterm on secure
-ttyva "/usr/libexec/getty Pc" xterm on secure
-ttyvb "/usr/libexec/getty Pc" xterm on secure</programlisting>
-
- <para xml:lang="en">The more virtual
- terminals, the more resources that are used. This can be
- problematic on systems with 8 MB RAM or less.
- Consider changing <literal>secure</literal> to
- <literal>insecure</literal>.</para>
-
- <important>
- <para xml:lang="en">In order to run an X server, at least one virtual
- terminal must be left to <literal>off</literal> for it
- to use. This means that only eleven of the Alt-function
- keys can be used as virtual consoles so that one is left
- for the X server.</para>
- </important>
-
- <para xml:lang="en">For example, to run X and eleven virtual consoles, the
- setting for virtual terminal 12 should be:</para>
-
- <programlisting xml:lang="en">ttyvb "/usr/libexec/getty Pc" xterm off secure</programlisting>
-
- <para xml:lang="en">The easiest way to activate the
- virtual consoles is to reboot.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="vty-from-x">
- <para xml:lang="en">How do I access the virtual consoles from X?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Use <keycombo action="simul"><keycap>Ctrl</keycap><keycap>Alt</keycap><keycap>F<replaceable>n</replaceable></keycap></keycombo>
- to switch back to a virtual console. Press <keycombo action="simul"><keycap>Ctrl</keycap><keycap>Alt</keycap><keycap>F1</keycap></keycombo>
- to return to the first virtual console.</para>
-
- <para xml:lang="en">Once at a text console, use
- <keycombo action="simul"><keycap>Alt</keycap><keycap>F<replaceable>n</replaceable></keycap></keycombo>
- to move between them.</para>
-
- <para xml:lang="en">To return to the X session, switch to the
- virtual console running X. If X was started from the
- command line using <command>startx</command>,
- the X session will attach to the next unused virtual
- console, not the text console from which it was invoked.
- For eight active virtual terminals, X will
- run on the ninth, so use <keycombo action="simul"><keycap>Alt</keycap><keycap>F9</keycap></keycombo>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="xdm-boot">
- <para xml:lang="en">How do I start <application>XDM</application> on
- boot?</para>
- </question>
-
- <answer>
- <para xml:lang="en">There are two schools of thought on how to start
- <citerefentry vendor="xfree86"><refentrytitle>xdm</refentrytitle><manvolnum>1</manvolnum></citerefentry>. One school starts <command>xdm</command>
- from <filename>/etc/ttys</filename> (see <citerefentry><refentrytitle>ttys</refentrytitle><manvolnum>5</manvolnum></citerefentry>)
- using the supplied example, while the other runs
- <command>xdm</command> from
- <filename>rc.local</filename> (see <citerefentry><refentrytitle>rc</refentrytitle><manvolnum>8</manvolnum></citerefentry>) or from an
- <filename>X</filename> script in
- <filename>/usr/local/etc/rc.d</filename>. Both are
- equally valid, and one may work in situations where the
- other does not. In both cases the result is the same: X
- will pop up a graphical login prompt.</para>
-
- <para xml:lang="en">The <citerefentry><refentrytitle>ttys</refentrytitle><manvolnum>5</manvolnum></citerefentry> method has the advantage of
- documenting which vty X will start on and passing the
- responsibility of restarting the X server on logout to
- <citerefentry><refentrytitle>init</refentrytitle><manvolnum>8</manvolnum></citerefentry>. The <citerefentry><refentrytitle>rc</refentrytitle><manvolnum>8</manvolnum></citerefentry> method makes it easy to
- <command>kill</command> <command>xdm</command> if there is
- a problem starting the X server.</para>
-
- <para xml:lang="en">If loaded from <citerefentry><refentrytitle>rc</refentrytitle><manvolnum>8</manvolnum></citerefentry>, <command>xdm</command>
- should be started without any arguments.
- <command>xdm</command> must start
- <emphasis>after</emphasis> <citerefentry><refentrytitle>getty</refentrytitle><manvolnum>8</manvolnum></citerefentry> runs, or else
- <command>getty</command> and <command>xdm</command> will
- conflict, locking out the console. The best way around
- this is to have the script sleep 10 seconds or so then
- launch <command>xdm</command>.</para>
-
- <para xml:lang="en">When starting <command>xdm</command> from
- <filename>/etc/ttys</filename>, there still is a chance of
- conflict between <command>xdm</command> and <citerefentry><refentrytitle>getty</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
- One way to avoid this is to add the <literal>vt</literal>
- number in
- <filename>/usr/local/lib/X11/xdm/Xservers</filename>:</para>
-
- <programlisting xml:lang="en">:0 local /usr/local/bin/X vt4</programlisting>
-
- <para xml:lang="en">The above example will direct the X server to run in
- <filename>/dev/ttyv3</filename>. Note the number is
- offset by one. The X server counts the vty from one,
- whereas the FreeBSD kernel numbers the vty from zero.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="xconsole-failure">
- <para xml:lang="en">Why do I get <errorname>Couldn't open
- console</errorname> when I run
- <command>xconsole</command>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">When <application>X</application> is started with
- <command>startx</command>, the permissions on
- <filename>/dev/console</filename> will
- <emphasis>not</emphasis> get changed, resulting in things
- like <command>xterm -C</command> and
- <command>xconsole</command> not working.</para>
-
- <para xml:lang="en">This is because of the way console permissions are set
- by default. On a multi-user system, one does not
- necessarily want just any user to be able to write on the
- system console. For users who are logging directly onto a
- machine with a VTY, the <citerefentry><refentrytitle>fbtab</refentrytitle><manvolnum>5</manvolnum></citerefentry> file exists to solve
- such problems.</para>
-
- <para xml:lang="en">In a nutshell, make sure an uncommented line of the
- form is in <filename>/etc/fbtab</filename> (see
- <citerefentry><refentrytitle>fbtab</refentrytitle><manvolnum>5</manvolnum></citerefentry>):</para>
-
- <programlisting xml:lang="en">/dev/ttyv0 0600 /dev/console</programlisting>
-
- <para xml:lang="en">It will ensure that whomever logs in on
- <filename>/dev/ttyv0</filename> will own the
- console.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ps2-x">
- <para xml:lang="en">Why does my PS/2 mouse misbehave under X?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The mouse and the mouse driver may have become out of
- synchronization. In rare cases, the driver may also
- erroneously report synchronization errors:</para>
-
- <programlisting xml:lang="en">psmintr: out of sync (xxxx != yyyy)</programlisting>
-
- <para xml:lang="en">If this happens, disable the synchronization check
- code by setting the driver flags for the PS/2 mouse driver
- to <literal>0x100</literal>. This can be easiest achieved
- by adding <literal>hint.psm.0.flags="0x100"</literal> to
- <filename>/boot/loader.conf</filename> and
- rebooting.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="mouse-button-reverse">
- <para xml:lang="en">How do I reverse the mouse buttons?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Type
- <command>xmodmap -e "pointer = 3 2 1"</command>. Add this
- command to <filename>~/.xinitrc</filename> or
- <filename>~/.xsession</filename> to make it happen
- automatically.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="install-splash">
- <para xml:lang="en">How do I install a splash screen and where do I find
- them?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The detailed answer for this question can be found in
- the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/boot-splash.html">Boot
- Time Splash Screens</link> section of the FreeBSD
- Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="windows-keys">
- <para xml:lang="en">Can I use the <keycap>Windows</keycap> keys on my
- keyboard in X?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes. Use <citerefentry vendor="xfree86"><refentrytitle>xmodmap</refentrytitle><manvolnum>1</manvolnum></citerefentry> to
- define which functions the keys should perform.</para>
-
- <para xml:lang="en">Assuming all Windows keyboards are
- standard, the keycodes for these three keys are the
- following:</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en"><keycode>115</keycode> —
- <keycap>Windows</keycap> key, between the left-hand
- <keycap>Ctrl</keycap> and <keycap>Alt</keycap>
- keys</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en"><keycode>116</keycode> —
- <keycap>Windows</keycap> key, to the right of
- <keycap>AltGr</keycap></para>
- </listitem>
-
- <listitem>
- <para xml:lang="en"><keycode>117</keycode> —
- <keycap>Menu</keycap>, to the left of the right-hand
- <keycap>Ctrl</keycap></para>
- </listitem>
- </itemizedlist>
-
- <para xml:lang="en">To have the left <keycap>Windows</keycap> key print a
- comma, try this.</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>xmodmap -e "keycode 115 = comma"</userinput></screen>
-
- <para xml:lang="en">To have the <keycap>Windows</keycap> key-mappings
- enabled automatically every time X is started, either put
- the <command>xmodmap</command> commands in
- <filename>~/.xinitrc</filename> or, preferably, create
- a <filename>~/.xmodmaprc</filename> and include the
- <command>xmodmap</command> options, one per line, then add
- the following line to
- <filename>~/.xinitrc</filename>:</para>
-
- <programlisting xml:lang="en">xmodmap $HOME/.xmodmaprc</programlisting>
-
- <para xml:lang="en">For example, to map the 3 keys to be
- <keycap>F13</keycap>, <keycap>F14</keycap>, and
- <keycap>F15</keycap>, respectively. This would make it
- easy to map them to useful functions within applications
- or the window manager.</para>
-
- <para xml:lang="en">To do this, put the following in
- <filename>~/.xmodmaprc</filename>.</para>
-
- <programlisting xml:lang="en">keycode 115 = F13
-keycode 116 = F14
-keycode 117 = F15</programlisting>
-
- <para xml:lang="en">For the <package>x11-wm/fvwm2</package> desktop
- manager, one could map the keys so that
- <keycap>F13</keycap> iconifies or de-iconifies the
- window the cursor is in, <keycap>F14</keycap> brings the
- window the cursor is in to the front or, if it is already
- at the front, pushes it to the back, and
- <keycap>F15</keycap> pops up the main Workplace
- menu even if the cursor is not on the
- desktop, which is useful when no part of
- the desktop is visible.</para>
-
- <para xml:lang="en">The following entries in
- <filename>~/.fvwmrc</filename> implement the
- aforementioned setup:</para>
-
- <programlisting xml:lang="en">Key F13 FTIWS A Iconify
-Key F14 FTIWS A RaiseLower
-Key F15 A A Menu Workplace Nop</programlisting>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="x-3d-acceleration">
- <para xml:lang="en">How can I get 3D hardware acceleration for
- <trademark class="registered">OpenGL</trademark>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The availability of 3D acceleration depends on the
- version of Xorg and the type of video
- chip. For an nVidia chip, use
- the binary drivers provided for FreeBSD by installing one of
- the following ports:</para>
-
- <para xml:lang="en">The latest versions of nVidia cards are supported
- by the <package>x11/nvidia-driver</package>
- port.</para>
-
- <para xml:lang="en">Older drivers are available as
- <package>x11/nvidia-driver-<replaceable>###</replaceable></package></para>
-
- <para xml:lang="en">nVidia provides detailed information on which
- card is supported by which driver on their web site: <uri xlink:href="http://www.nvidia.com/object/IO_32667.html">http://www.nvidia.com/object/IO_32667.html</uri>.</para>
-
- <para xml:lang="en">For Matrox G200/G400, check the
- <package>x11-drivers/xf86-video-mga</package>
- port.</para>
-
- <para xml:lang="en">For ATI Rage 128 and Radeon see
- <citerefentry vendor="xorg"><refentrytitle>ati</refentrytitle><manvolnum>4</manvolnum></citerefentry>, <citerefentry vendor="xorg"><refentrytitle>r128</refentrytitle><manvolnum>4</manvolnum></citerefentry> and <citerefentry vendor="xorg"><refentrytitle>radeon</refentrytitle><manvolnum>4</manvolnum></citerefentry>.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="networking">
- <title xml:lang="en">Networking</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="diskless-booting">
- <para xml:lang="en">Where can I get information on <quote>diskless
- booting</quote>?</para>
- </question>
-
- <answer>
- <para xml:lang="en"><quote>Diskless booting</quote> means that the FreeBSD
- box is booted over a network, and reads the necessary
- files from a server instead of its hard disk. For full
- details, see <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/network-diskless.html">the
- Handbook entry on diskless booting</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="router">
- <para xml:lang="en">Can a FreeBSD box be used as a dedicated network
- router?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes. Refer to the Handbook entry on <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/advanced-networking.html">advanced
- networking</link>, specifically the section on <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/network-routing.html">routing
- and gateways</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="win95-connection">
- <para xml:lang="en">Can I connect my <trademark class="registered">Windows</trademark> box to the Internet via
- FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Typically, people who ask this question have two PCs
- at home, one with FreeBSD and one with some version of
- <trademark class="registered">Windows</trademark> the idea is to use the FreeBSD box to connect to
- the Internet and then be able to access the Internet from
- the <trademark class="registered">Windows</trademark> box through the FreeBSD box. This is really
- just a special case of the previous question and works
- perfectly well.</para>
-
- <para xml:lang="en">Dialup users must use <option>-nat</option>
- and set <literal>gateway_enable</literal> to
- <emphasis>YES</emphasis> in
- <filename>/etc/rc.conf</filename>. For more information,
- refer to <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> or the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/userppp.html">Handbook
- entry on user PPP</link>.</para>
-
- <para xml:lang="en">If the connection to the Internet is over Ethernet,
- use <citerefentry><refentrytitle>natd</refentrytitle><manvolnum>8</manvolnum></citerefentry>. A tutorial can be found in the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/firewalls-ipfw.html#network-natd">natd</link>
- section of the Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="slip-ppp-support">
- <para xml:lang="en">Does FreeBSD support PPP?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes. <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> provides support for both incoming
- and outgoing connections.</para>
-
- <para xml:lang="en">For more information on how to use this, refer to
- the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/ppp-and-slip.html">Handbook
- chapter on PPP</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="natd">
- <para xml:lang="en">Does FreeBSD support NAT or Masquerading?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes. For instructions on how to use NAT over a PPP
- connection, see the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/userppp.html">Handbook
- entry on PPP</link>. To use NAT over
- some other sort of network connection, look at the
- <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/firewalls-ipfw.html#network-natd">natd</link>
- section of the Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ethernet-aliases">
- <para xml:lang="en">How can I set up Ethernet aliases?</para>
- </question>
-
- <answer>
- <para xml:lang="en">If the alias is on the same subnet as an address
- already configured on the interface, add
- <literal>netmask 0xffffffff</literal> to this
- command:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>ifconfig <replaceable>ed0</replaceable> alias <replaceable>192.0.2.2 </replaceable>netmask 0xffffffff</userinput></screen>
-
- <para xml:lang="en">Otherwise, specify the network address and
- netmask as usual:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>ifconfig <replaceable>ed0</replaceable> alias <replaceable>172.16.141.5</replaceable> netmask 0xffffff00</userinput></screen>
-
- <para xml:lang="en">More information can be found in the FreeBSD <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/configtuning-virtual-hosts.html">Handbook</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="nfs-linux">
- <para xml:lang="en">Why can I not NFS-mount from a <trademark class="registered">Linux</trademark> box?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Some versions of the <trademark class="registered">Linux</trademark> NFS code only accept
- mount requests from a privileged port; try to issue the
- following command:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>mount -o -P linuxbox:/blah /mnt</userinput></screen>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="exports-errors">
- <para xml:lang="en">Why does <command>mountd</command> keep telling me it
- <errorname>can't change attributes</errorname> and that I
- have a <errorname>bad exports list</errorname> on my FreeBSD
- NFS server?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The most frequent problem is not understanding the
- correct format of <filename>/etc/exports</filename>.
- Review <citerefentry><refentrytitle>exports</refentrytitle><manvolnum>5</manvolnum></citerefentry> and the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/network-nfs.html">NFS</link>
- entry in the Handbook, especially the section on <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/network-nfs.html#configuring-nfs">configuring
- NFS</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ip-multicast">
- <para xml:lang="en">How do I enable IP multicast support?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Install the <package>net/mrouted</package> package
- or port and add
- <literal>mrouted_enable="YES"</literal> to
- <filename>/etc/rc.conf</filename> start this service at
- boot time.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="fqdn-hosts">
- <para xml:lang="en">Why do I have to use the FQDN for hosts on my
- site?</para>
- </question>
-
- <answer>
- <para xml:lang="en">See the answer in the FreeBSD <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/mail-trouble.html">Handbook</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="network-permission-denied">
- <para xml:lang="en">Why do I get an error, <errorname>Permission
- denied</errorname>, for all networking
- operations?</para>
- </question>
-
- <answer>
- <para xml:lang="en">If the kernel is compiled with the
- <literal>IPFIREWALL</literal> option, be aware
- that the default policy is to deny all packets that are
- not explicitly allowed.</para>
-
- <para xml:lang="en">If the firewall is unintentionally misconfigured,
- restore network operability by
- typing the following as <systemitem class="username">root</systemitem>:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>ipfw add 65534 allow all from any to any</userinput></screen>
-
- <para xml:lang="en">Consider setting
- <literal>firewall_type="open"</literal> in
- <filename>/etc/rc.conf</filename>.</para>
-
- <para xml:lang="en">For further information on configuring this
- firewall, see the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/firewalls-ipfw.html">Handbook
- chapter</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ipfw-fwd">
- <para xml:lang="en">Why is my <command>ipfw</command> <quote>fwd</quote>
- rule to redirect a service to another machine not
- working?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Possibly because network address translation (NAT) is
- needed instead of just forwarding packets. A
- <quote>fwd</quote> rule only forwards packets, it does not
- actually change the data inside the packet. Consider this
- rule:</para>
-
- <screen xml:lang="en">01000 fwd <replaceable>10.0.0.1</replaceable> from any to <replaceable>foo 21</replaceable></screen>
-
- <para xml:lang="en">When a packet with a destination address of
- <replaceable>foo</replaceable> arrives at the machine with
- this rule, the packet is forwarded to
- <replaceable>10.0.0.1</replaceable>, but it still has the
- destination address of <replaceable>foo</replaceable>.
- The destination address of the packet is
- not changed to
- <replaceable>10.0.0.1</replaceable>. Most machines would
- probably drop a packet that they receive with a
- destination address that is not their own. Therefore,
- using a <quote>fwd</quote> rule does not often work the
- way the user expects. This behavior is a feature and not
- a bug.</para>
-
- <para xml:lang="en">See the <link linkend="service-redirect"><acronym>FAQ</acronym> about
- redirecting services</link>, the <citerefentry><refentrytitle>natd</refentrytitle><manvolnum>8</manvolnum></citerefentry> manual, or
- one of the several port redirecting utilities in the <link xlink:href="@@URL_RELPREFIX@@/ports/index.html">Ports
- Collection</link> for a correct way to do this.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="service-redirect">
- <para xml:lang="en">How can I redirect service requests from one machine
- to another?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FTP and other service requests can be redirected with
- the <package>sysutils/socket</package> package or port.
- Replace the entry for the service in
- <filename>/etc/inetd.conf</filename> to call
- <command>socket</command>, as seen in this example for
- <application>ftpd</application>:</para>
-
- <programlisting xml:lang="en">ftp stream tcp nowait nobody /usr/local/bin/socket socket <replaceable>ftp.example.com</replaceable> <replaceable>ftp</replaceable></programlisting>
-
- <para xml:lang="en">where <replaceable>ftp.example.com</replaceable> and
- <replaceable>ftp</replaceable> are the host and port to
- redirect to, respectively.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="bandwidth-mgr-tool">
- <para xml:lang="en">Where can I get a bandwidth management tool?</para>
- </question>
-
- <answer>
- <para xml:lang="en">There are three bandwidth management tools available
- for FreeBSD. <citerefentry><refentrytitle>dummynet</refentrytitle><manvolnum>4</manvolnum></citerefentry> is integrated into FreeBSD as
- part of <citerefentry><refentrytitle>ipfw</refentrytitle><manvolnum>4</manvolnum></citerefentry>. <link xlink:href="http://www.sonycsl.co.jp/person/kjc/programs.html">ALTQ</link>
- has been integrated into FreeBSD as part of <citerefentry><refentrytitle>pf</refentrytitle><manvolnum>4</manvolnum></citerefentry>.
- Bandwidth Manager from <link xlink:href="http://www.etinc.com/">Emerging
- Technologies</link> is a commercial product.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="bpf-not-configured">
- <para xml:lang="en">Why do I get <errorname>/dev/bpf0: device not
- configured</errorname>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The running application requires the Berkeley
- Packet Filter (<citerefentry><refentrytitle>bpf</refentrytitle><manvolnum>4</manvolnum></citerefentry>), but it was removed from a
- custom kernel. Add this to the kernel config file and
- build a new kernel:</para>
-
- <programlisting xml:lang="en">device bpf # Berkeley Packet Filter</programlisting>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="mount-smb-share">
- <para xml:lang="en">How do I mount a disk from a <trademark class="registered">Windows</trademark> machine that is
- on my network, like smbmount in <trademark class="registered">Linux</trademark>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Use the <application>SMBFS</application> toolset. It
- includes a set of kernel modifications and a set of
- userland programs. The programs and information are
- available as <citerefentry><refentrytitle>mount_smbfs</refentrytitle><manvolnum>8</manvolnum></citerefentry> in the base
- system.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="icmp-response-bw-limit">
- <para xml:lang="en">What are these messages about: <errorname>Limiting
- icmp/open port/closed port response</errorname> in my
- log files?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This kernel message indicates that some activity is
- provoking it to send a large amount of ICMP or TCP reset
- (RST) responses. ICMP responses are
- often generated as a result of attempted connections to
- unused UDP ports. TCP resets are generated as a result of
- attempted connections to unopened TCP ports. Among
- others, these are the kinds of activities which may cause
- these messages:</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en">Brute-force denial of service (DoS) attacks (as
- opposed to single-packet attacks which exploit a
- specific vulnerability).</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Port scans which attempt to connect to a large
- number of ports (as opposed to only trying a few
- well-known ports).</para>
- </listitem>
- </itemizedlist>
-
- <para xml:lang="en">The first number in the message indicates how many
- packets the kernel would have sent if the limit was not in
- place, and the second indicates the limit. This limit
- is controlled using
- <varname>net.inet.icmp.icmplim</varname>. This example
- sets the limit to <literal>300</literal>
- packets per second:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>sysctl net.inet.icmp.icmplim=300</userinput></screen>
-
- <para xml:lang="en">To disable these messages
- without disabling response
- limiting, use
- <varname>net.inet.icmp.icmplim_output</varname>
- to disable the output:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>sysctl net.inet.icmp.icmplim_output=0</userinput></screen>
-
- <para xml:lang="en">Finally, to disable response limiting completely,
- set <varname>net.inet.icmp.icmplim</varname> to
- <literal>0</literal>. Disabling response limiting is
- discouraged for the reasons listed above.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="unknown-hw-addr-format">
- <para xml:lang="en">What are these <errorname>arp: unknown hardware
- address format</errorname> error messages?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This means that some device on the local Ethernet is
- using a MAC address in a format that FreeBSD does not
- recognize. This is probably caused by someone
- experimenting with an Ethernet card somewhere else on the
- network. This is most commonly seen on cable modem
- networks. It is harmless, and should not affect the
- performance of the FreeBSD system.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="arp-wrong-iface">
- <para xml:lang="en">Why do I keep seeing messages like:
- <errorname>192.168.0.10 is on
- fxp1 but got reply from 00:15:17:67:cf:82 on
- rl0</errorname>, and how do I disable it?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Because a packet is coming from outside the network
- unexpectedly. To disable them, set
- <varname>net.link.ether.inet.log_arp_wrong_iface</varname>
- to <literal>0</literal>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ipv6-only">
- <para xml:lang="en">How do I compile an IPv6 only kernel?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Configure your kernel with these settings:
-
- <screen xml:lang="en">include GENERIC
-ident GENERIC-IPV6ONLY
-makeoptions MKMODULESENV+="WITHOUT_INET_SUPPORT="
-nooptions INET
-nodevice gre</screen></para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="security">
- <title xml:lang="en">Security</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="sandbox">
- <para xml:lang="en">What is a sandbox?</para>
- </question>
- <answer>
- <para xml:lang="en"><quote>Sandbox</quote> is a security term. It can
- mean two things:</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en">A process which is placed inside a set of virtual
- walls that are designed to prevent someone who breaks
- into the process from being able to break into the
- wider system.</para>
-
- <para xml:lang="en">The process is only able to run inside the walls.
- Since nothing the process does in regards to executing
- code is supposed to be able to breach the walls, a
- detailed audit of its code is not needed in order to
- be able to say certain things about its
- security.</para>
-
- <para xml:lang="en">The walls might be a user ID, for example.
- This is the definition used in the <citerefentry><refentrytitle>security</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- and <citerefentry><refentrytitle>named</refentrytitle><manvolnum>8</manvolnum></citerefentry> man pages.</para>
-
- <para xml:lang="en">Take the <literal>ntalk</literal> service, for
- example (see <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>). This service used to run
- as user ID <systemitem class="username">root</systemitem>. Now it runs as
- user ID <systemitem class="username">tty</systemitem>. The <systemitem class="username">tty</systemitem> user is a sandbox
- designed to make it more difficult for someone who has
- successfully hacked into the system via
- <literal>ntalk</literal> from being able to hack
- beyond that user ID.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">A process which is placed inside a simulation of
- the machine. It means that someone who is able to
- break into the process may believe that he can break
- into the wider machine but is, in fact, only breaking
- into a simulation of that machine and not modifying
- any real data.</para>
-
- <para xml:lang="en">The most common way to accomplish this is to build
- a simulated environment in a subdirectory and then run
- the processes in that directory chrooted so that
- <filename>/</filename> for that process is this
- directory, not the real <filename>/</filename> of the
- system).</para>
-
- <para xml:lang="en">Another common use is to mount an underlying file
- system read-only and then create a file system layer
- on top of it that gives a process a seemingly
- writeable view into that file system. The process may
- believe it is able to write to those files, but only
- the process sees the effects — other processes
- in the system do not, necessarily.</para>
-
- <para xml:lang="en">An attempt is made to make this sort of sandbox so
- transparent that the user (or hacker) does not realize
- that he is sitting in it.</para>
- </listitem>
- </itemizedlist>
-
- <para xml:lang="en"><trademark class="registered">UNIX</trademark> implements two core sandboxes. One is at the
- process level, and one is at the userid level.</para>
-
- <para xml:lang="en">Every <trademark class="registered">UNIX</trademark> process is completely firewalled off from
- every other <trademark class="registered">UNIX</trademark> process. One process cannot modify the
- address space of another.</para>
-
- <para xml:lang="en">A <trademark class="registered">UNIX</trademark> process is owned by a particular userid. If
- the user ID is not the <systemitem class="username">root</systemitem> user, it serves to
- firewall the process off from processes owned by other
- users. The user ID is also used to firewall off
- on-disk data.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="securelevel">
- <para xml:lang="en">What is securelevel?</para>
- </question>
-
- <answer>
- <para xml:lang="en"><literal>securelevel</literal> is a security
- mechanism implemented in the kernel. When the securelevel
- is positive, the kernel restricts certain tasks; not even
- the superuser (<systemitem class="username">root</systemitem>) is allowed to do
- them. The securelevel mechanism limits the ability
- to:</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en">Unset certain file flags, such as
- <literal>schg</literal> (the system immutable
- flag).</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Write to kernel memory via
- <filename>/dev/mem</filename> and
- <filename>/dev/kmem</filename>.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Load kernel modules.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Alter firewall rules.</para>
- </listitem>
- </itemizedlist>
-
- <para xml:lang="en">To check the status of the securelevel on a running
- system:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>sysctl -n kern.securelevel</userinput></screen>
-
- <para xml:lang="en">The output contains the current value of the
- securelevel. If it is greater than 0, at
- least some of the securelevel's protections are
- enabled.</para>
-
- <para xml:lang="en">The securelevel of a running system cannot be lowered
- as this would defeat its purpose. If a task requires that
- the securelevel be non-positive, change the
- <varname>kern_securelevel</varname> and
- <varname>kern_securelevel_enable</varname> variables in
- <filename>/etc/rc.conf</filename> and reboot.</para>
-
- <para xml:lang="en">For more information on securelevel and the specific
- things all the levels do, consult <citerefentry><refentrytitle>init</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
-
- <warning>
- <para xml:lang="en">Securelevel is not a silver bullet; it has many
- known deficiencies. More often than not, it provides a
- false sense of security.</para>
-
- <para xml:lang="en">One of its biggest problems is that in order for it
- to be at all effective, all files used in the boot
- process up until the securelevel is set must be
- protected. If an attacker can get the system to execute
- their code prior to the securelevel being set (which
- happens quite late in the boot process since some things
- the system must do at start-up cannot be done at an
- elevated securelevel), its protections are invalidated.
- While this task of protecting all files used in the boot
- process is not technically impossible, if it is
- achieved, system maintenance will become a nightmare
- since one would have to take the system down, at least
- to single-user mode, to modify a configuration
- file.</para>
-
- <para xml:lang="en">This point and others are often discussed on the
- mailing lists, particularly the <link xlink:href="http://lists.FreeBSD.org/mailman/listinfo/freebsd-security">FreeBSD security mailing list</link>.
- Search the archives <link xlink:href="@@URL_RELPREFIX@@/search/index.html">here</link>
- for an extensive discussion. A more fine-grained
- mechanism is preferred.</para>
- </warning>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="extra-named-port">
- <para xml:lang="en"><application>BIND9</application>
- (<command>named</command>) is listening on some
- high-numbered ports. What is going on?</para>
- </question>
-
- <answer>
- <para xml:lang="en">BIND uses a random high-numbered port for outgoing
- queries. Recent versions of it choose a new, random UDP
- port for each query. This may cause problems for some
- network configurations, especially if a firewall blocks
- incoming UDP packets on particular ports. To
- get past that firewall, try the
- <literal>avoid-v4-udp-ports</literal> and
- <literal>avoid-v6-udp-ports</literal> options to avoid
- selecting random port numbers within a blocked
- range.</para>
-
- <warning>
- <para xml:lang="en">If a port number (like 53) is specified via the
- <literal>query-source</literal> or
- <literal>query-source-v6</literal> options in
- <filename>/usr/local/etc/namedb/named.conf</filename>,
- randomized
- port selection will not be used. It is strongly
- recommended that these options not be used to specify
- fixed port numbers.</para>
- </warning>
-
- <para xml:lang="en">Congratulations, by the way. It is good practice to
- read <citerefentry><refentrytitle>sockstat</refentrytitle><manvolnum>1</manvolnum></citerefentry> output and notice odd
- things!</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="sendmail-port-587">
- <para xml:lang="en">The <application>Sendmail</application> daemon is
- listening on port 587 as well as the standard port 25!
- What is going on?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Recent versions of <application>Sendmail</application>
- support a mail submission feature that runs over port 587.
- This is not yet widely supported, but is growing in
- popularity.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="toor-account">
- <para xml:lang="en">What is this UID 0 <systemitem class="username">toor</systemitem> account? Have I been
- compromised?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Do not worry. <systemitem class="username">toor</systemitem> is an
- <quote>alternative</quote> superuser account, where toor
- is root spelled backwards. It is intended to be used with
- a non-standard shell so the default shell for <systemitem class="username">root</systemitem> does not need to
- change. This is important as shells which are not part of
- the base distribution, but are instead installed from
- ports or packages, are installed in
- <filename>/usr/local/bin</filename> which, by default,
- resides on a different file system. If <systemitem class="username">root</systemitem>'s shell is located in
- <filename>/usr/local/bin</filename> and the
- file system
- containing <filename>/usr/local/bin</filename>) is not
- mounted, <systemitem class="username">root</systemitem> will not be able to
- log in to fix a problem and will have to reboot into
- single-user mode in order to enter the path to a
- shell.</para>
-
- <para xml:lang="en">Some people use <systemitem class="username">toor</systemitem> for day-to-day
- <systemitem class="username">root</systemitem> tasks with
- a non-standard shell, leaving <systemitem class="username">root</systemitem>, with a standard
- shell, for single-user mode or emergencies. By default, a
- user cannot log in using <systemitem class="username">toor</systemitem> as it does not have a
- password, so log in as <systemitem class="username">root</systemitem> and set a password
- for <systemitem class="username">toor</systemitem> before
- using it to login.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="ppp">
- <title xml:lang="en">PPP</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="userppp">
- <para xml:lang="en">I cannot make <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> work. What am I doing
- wrong?</para>
- </question>
-
- <answer>
- <para xml:lang="en">First, read <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> and
- the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/ppp-and-slip.html#userppp">PPP
- section of the Handbook</link>. To assist in
- troubleshooting, enable logging with the
- following command:</para>
-
- <programlisting xml:lang="en">set log Phase Chat Connect Carrier lcp ipcp ccp command</programlisting>
-
- <para xml:lang="en">This command may be typed at the <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> command
- prompt or it may be entered at the start of the
- <literal>default</literal> section
- in <filename>/etc/ppp/ppp.conf</filename>. Make sure that
- <filename>/etc/syslog.conf</filename> contains the lines
- below and the file <filename>/var/log/ppp.log</filename>
- exists:</para>
-
- <programlisting xml:lang="en">!ppp
-*.* /var/log/ppp.log</programlisting>
-
- <para xml:lang="en">A lot about what is going can be learned from the log
- file. Do not worry if it does not all make sense as
- it may make sense to someone else.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-hangs">
- <para xml:lang="en">Why does <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> hang when I run it?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This is usually because the hostname will not
- resolve. The best way to fix this is to make sure that
- <filename>/etc/hosts</filename> is read first by the
- by ensuring that the <literal>hosts</literal> line is
- listed first in <filename>/etc/host.conf</filename>.
- Then, put an entry in <filename>/etc/hosts</filename> for
- the local machine. If there is no local network, change
- the <systemitem>localhost</systemitem> line:</para>
-
- <programlisting xml:lang="en">127.0.0.1 foo.example.com foo localhost</programlisting>
-
- <para xml:lang="en">Otherwise, add another entry for the host.
- Consult the relevant manual pages for more details.</para>
-
- <para xml:lang="en">When finished, verify that this command is successful:
- <command>ping -c1 `hostname`</command>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-nodial-auto">
- <para xml:lang="en">Why will <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> not dial in
- <literal>-auto</literal> mode?</para>
- </question>
-
- <answer>
- <para xml:lang="en">First, check that a default route exists. This
- command should display two entries:</para>
-
- <programlisting xml:lang="en">Destination Gateway Flags Refs Use Netif Expire
-default 10.0.0.2 UGSc 0 0 tun0
-10.0.0.2 10.0.0.1 UH 0 0 tun0</programlisting>
-
- <para xml:lang="en">If
- a default route is not listed, make sure that the
- <literal>HISADDR</literal> line has been added to
- <filename>/etc/ppp/ppp.conf</filename>.</para>
-
- <para xml:lang="en">Another reason for the default route line being
- missing is that a default
- route has been added to <filename>/etc/rc.conf</filename>
- and this line is missing
- from <filename>/etc/ppp/ppp.conf</filename>:</para>
-
- <programlisting xml:lang="en">delete ALL</programlisting>
-
- <para xml:lang="en">If this is the case, go back to the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/userppp.html#userppp-final">Final
- System Configuration</link> section of the
- Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="no-route-to-host">
- <para xml:lang="en">What does <errorname>No route to host</errorname>
- mean?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This error is usually because the following section
- is missing in
- <filename>/etc/ppp/ppp.linkup</filename>:</para>
-
- <programlisting xml:lang="en">MYADDR:
- delete ALL
- add 0 0 HISADDR</programlisting>
-
- <para xml:lang="en">This is only necessary for a dynamic IP address or
- when the address of the default gateway is unknown. When
- using interactive mode, the following can be typed in
- after entering packet mode. Packet mode
- is indicated by the capitalized <acronym>PPP</acronym> in
- the prompt:</para>
-
- <programlisting xml:lang="en">delete ALL
-add 0 0 HISADDR</programlisting>
-
- <para xml:lang="en">Refer to the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/userppp.html#userppp-dynamicip">PPP
- and Dynamic IP addresses</link> section of the Handbook
- for further details.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="connection-threeminutedrop">
- <para xml:lang="en">Why does my connection drop after about 3
- minutes?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The default PPP timeout is 3 minutes. This can be
- adjusted with the following line:</para>
-
- <programlisting xml:lang="en">set timeout <replaceable>NNN</replaceable></programlisting>
-
- <para xml:lang="en">where <replaceable>NNN</replaceable> is the number of
- seconds of inactivity before the connection is closed. If
- <replaceable>NNN</replaceable> is zero, the connection is
- never closed due to a timeout. It is possible to put this
- command in <filename>ppp.conf</filename>, or to type it at
- the prompt in interactive mode. It is also possible to
- adjust it on the fly while the line is active by
- connecting to <application>ppp</application>'s server
- socket using <citerefentry><refentrytitle>telnet</refentrytitle><manvolnum>1</manvolnum></citerefentry> or <citerefentry><refentrytitle>pppctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>. Refer to
- the <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> man page for further details.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-drop-heavy-load">
- <para xml:lang="en">Why does my connection drop under heavy load?</para>
- </question>
-
- <answer>
- <para xml:lang="en">If Link Quality Reporting (<acronym>LQR</acronym>) is
- configured, it is possible that too many
- <acronym>LQR</acronym> packets are lost between the FreeBSD
- system and the peer. <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> deduces that the line
- must therefore be bad, and disconnects.
- <acronym>LQR</acronym> is disabled by default and can be
- enabled with the following line:</para>
-
- <programlisting xml:lang="en">enable lqr</programlisting>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-drop-random">
- <para xml:lang="en">Why does my connection drop after a random amount of
- time?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Sometimes, on a noisy phone line or even on a line
- with call waiting enabled, the modem may hang up because
- it incorrectly thinks that it lost carrier.</para>
-
- <para xml:lang="en">There is a setting on most modems for determining how
- tolerant it should be to temporary losses of carrier.
- Refer to the modem manual for details.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-hangs-random">
- <para xml:lang="en">Why does my connection hang after a random amount of
- time?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Many people experience hung connections with no
- apparent explanation. The first thing to establish is
- which side of the link is hung.</para>
-
- <para xml:lang="en">When using an external modem, try
- using <citerefentry><refentrytitle>ping</refentrytitle><manvolnum>8</manvolnum></citerefentry> to see if the <acronym>TD</acronym>
- light is flashing when data is transmitted. If it flashes
- but the <acronym>RD</acronym> light does not, the
- problem is with the remote end. If <acronym>TD</acronym>
- does not flash, the problem is local. With an internal
- modem, use the <literal>set
- server</literal> command in
- <filename>ppp.conf</filename>. When the hang occurs,
- connect to <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> using <citerefentry><refentrytitle>pppctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>. If the
- network connection suddenly revives due to the activity on
- the diagnostic socket, or if it will not
- connect but the <literal>set socket</literal>
- command succeeded at startup time, the problem is local.
- If it can connect but things are still hung, enable local
- logging with <literal>set log local async</literal>
- and use <citerefentry><refentrytitle>ping</refentrytitle><manvolnum>8</manvolnum></citerefentry> from another window or terminal to
- make use of the link. The async logging will show the
- data being transmitted and received on the link. If data
- is going out and not coming back, the problem is
- remote.</para>
-
- <para xml:lang="en">Having established whether the problem is local or
- remote, there are now two possibilities:</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en">If the problem is remote, read on entry <xref linkend="ppp-remote-not-responding"/>.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">If the problem is local, read on entry <xref linkend="ppp-hung"/>.</para>
- </listitem>
- </itemizedlist>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-remote-not-responding">
- <para xml:lang="en">The remote end is not responding. What can I
- do?</para>
- </question>
-
- <answer>
- <para xml:lang="en">There is very little that can be done about this.
- Many ISPs will refuse to help users not running a
- <trademark class="registered">Microsoft</trademark> OS. Add <literal>enable lqr</literal> to
- <filename>/etc/ppp/ppp.conf</filename>, allowing
- <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> to detect the remote failure and hang up.
- This detection is relatively slow and therefore not that
- useful.</para>
-
- <para xml:lang="en">First, try disabling all local compression by adding
- the following to the configuration:</para>
-
- <programlisting xml:lang="en">disable pred1 deflate deflate24 protocomp acfcomp shortseq vj
-deny pred1 deflate deflate24 protocomp acfcomp shortseq vj</programlisting>
-
- <para xml:lang="en">Then reconnect to ensure that this makes no
- difference. If things improve or if the problem is solved
- completely, determine which setting makes the difference
- through trial and error. This is good information for
- the ISP, although it may make
- it apparent that it is not a <trademark class="registered">Microsoft</trademark> system.</para>
-
- <para xml:lang="en">Before contacting the ISP, enable async logging
- locally and wait until the connection hangs again. This
- may use up quite a bit of disk space. The last data read
- from the port may be of interest. It is usually ASCII
- data, and may even describe the problem (<errorname>Memory
- fault</errorname>, <errorname>Core
- dumped</errorname>).</para>
-
- <para xml:lang="en">If the ISP is helpful, they should be able to enable
- logging on their end, then when the next link drop occurs,
- they may be able to tell why their side is having a
- problem.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-hung">
- <para xml:lang="en"><citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> has hung. What can I do?</para>
- </question>
-
- <answer>
- <para xml:lang="en">In this case, rebuild <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> with
- debugging information, and then use <citerefentry><refentrytitle>gdb</refentrytitle><manvolnum>1</manvolnum></citerefentry> to grab a
- stack trace from the <application>ppp</application>
- process that is stuck. To rebuild the
- <application>ppp</application> utility with debugging
- information, type:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>cd /usr/src/usr.sbin/ppp</userinput>
-<prompt>#</prompt> <userinput>env DEBUG_FLAGS='-g' make clean</userinput>
-<prompt>#</prompt> <userinput>env DEBUG_FLAGS='-g' make install</userinput></screen>
-
- <para xml:lang="en">Then, restart <application>ppp</application>
- and wait until it hangs again. When the debug build of
- <application>ppp</application> hangs, start
- <application>gdb</application> on the stuck process by
- typing:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>gdb ppp `pgrep ppp`</userinput></screen>
-
- <para xml:lang="en">At the <application>gdb</application> prompt,
- use the <command>bt</command> or <command>where</command>
- commands to get a stack trace. Save the output of the
- <application>gdb</application> session, and
- <quote>detach</quote> from the running process by typing
- <command>quit</command>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-same-magic">
- <para xml:lang="en">I keep seeing errors about magic being the same. What
- does it mean?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Occasionally, just after connecting, there may be
- messages in the log that say <errorname>Magic is
- same</errorname>. Sometimes, these messages are
- harmless, and sometimes one side or the other exits. Most
- PPP implementations cannot survive this problem, and even
- if the link seems to come up, there will be repeated
- configure requests and configure acknowledgments in the
- log file until <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> eventually gives up and closes
- the connection.</para>
-
- <para xml:lang="en">This normally happens on server machines with slow
- disks that are spawning a <citerefentry><refentrytitle>getty</refentrytitle><manvolnum>8</manvolnum></citerefentry> on the port, and
- executing <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> from a login script or program after
- login. There were reports of it happening consistently
- when using slirp. The reason is that in the time taken
- between <citerefentry><refentrytitle>getty</refentrytitle><manvolnum>8</manvolnum></citerefentry> exiting and <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> starting,
- the client-side <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> starts sending Line Control
- Protocol (LCP) packets. Because ECHO is still switched on
- for the port on the server, the client <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> sees
- these packets <quote>reflect</quote> back.</para>
-
- <para xml:lang="en">One part of the LCP negotiation is to establish a
- magic number for each side of the link so that
- <quote>reflections</quote> can be detected. The protocol
- says that when the peer tries to negotiate the same magic
- number, a NAK should be sent and a new magic number should
- be chosen. During the period that the server port has
- ECHO turned on, the client <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> sends LCP packets,
- sees the same magic in the reflected packet and NAKs it.
- It also sees the NAK reflect (which also means <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- must change its magic). This produces a potentially
- enormous number of magic number changes, all of which are
- happily piling into the server's tty buffer. As soon as
- <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> starts on the server, it is flooded with magic
- number changes and almost immediately decides it has tried
- enough to negotiate LCP and gives up. Meanwhile, the
- client, who no longer sees the reflections, becomes happy
- just in time to see a hangup from the server.</para>
-
- <para xml:lang="en">This can be avoided by allowing the peer to start
- negotiating with the following line in
- <filename>ppp.conf</filename>:</para>
-
- <programlisting xml:lang="en">set openmode passive</programlisting>
-
- <para xml:lang="en">This tells <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> to wait for the server to
- initiate LCP negotiations. Some servers however may never
- initiate negotiations. In this case, try
- something like:</para>
-
- <programlisting xml:lang="en">set openmode active 3</programlisting>
-
- <para xml:lang="en">This tells <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> to be passive for 3 seconds,
- and then to start sending LCP requests. If the peer
- starts sending requests during this period, <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- will immediately respond rather than waiting for the full
- 3 second period.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-lcp-constant">
- <para xml:lang="en">LCP negotiations continue until the connection is
- closed. What is wrong?</para>
- </question>
-
- <answer>
- <para xml:lang="en">There is currently an implementation mis-feature in
- <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> where it does not associate LCP, CCP &amp;
- IPCP responses with their original requests. As a result,
- if one PPP implementation is more than 6 seconds slower
- than the other side, the other side will send two
- additional LCP configuration requests. This is
- fatal.</para>
-
- <para xml:lang="en">Consider two implementations,
- <systemitem>A</systemitem> and <systemitem>B</systemitem>.
- <systemitem>A</systemitem> starts sending LCP requests
- immediately after connecting and
- <systemitem>B</systemitem> takes 7 seconds to start. When
- <systemitem>B</systemitem> starts,
- <systemitem>A</systemitem> has sent 3 LCP REQs. We are
- assuming the line has ECHO switched off, otherwise we
- would see magic number problems as described in the
- previous section. <systemitem>B</systemitem> sends a REQ,
- then an ACK to the first of <systemitem>A</systemitem>'s
- REQs. This results in <systemitem>A</systemitem> entering
- the <acronym>OPENED</acronym> state and sending and ACK
- (the first) back to <systemitem>B</systemitem>. In the
- meantime, <systemitem>B</systemitem> sends back two more
- ACKs in response to the two additional REQs sent by
- <systemitem>A</systemitem> before
- <systemitem>B</systemitem> started up.
- <systemitem>B</systemitem> then receives the first ACK
- from <systemitem>A</systemitem> and enters the
- <acronym>OPENED</acronym> state.
- <systemitem>A</systemitem> receives the second ACK from
- <systemitem>B</systemitem> and goes back to the
- <acronym>REQ-SENT</acronym> state, sending another (forth)
- REQ as per the RFC. It then receives the third ACK and
- enters the <acronym>OPENED</acronym> state. In the
- meantime, <systemitem>B</systemitem> receives the forth
- REQ from <systemitem>A</systemitem>, resulting in it
- reverting to the <acronym>ACK-SENT</acronym> state and
- sending another (second) REQ and (forth) ACK as per the
- RFC. <systemitem>A</systemitem> gets the REQ, goes into
- <acronym>REQ-SENT</acronym> and sends another REQ. It
- immediately receives the following ACK and enters
- <acronym>OPENED</acronym>.</para>
-
- <para xml:lang="en">This goes on until one side figures out that they are
- getting nowhere and gives up.</para>
-
- <para xml:lang="en">The best way to avoid this is to configure one side to
- be <literal>passive</literal> — that is, make one
- side wait for the other to start negotiating. This can be
- done with the following command:</para>
-
- <programlisting xml:lang="en">set openmode passive</programlisting>
-
- <para xml:lang="en">Care should be taken with this option. This command
- can also be used to limit the amount of time that
- <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> waits for the peer to begin
- negotiations:</para>
-
- <programlisting xml:lang="en">set stopped <replaceable>N</replaceable></programlisting>
-
- <para xml:lang="en">Alternatively, the following command (where
- <replaceable>N</replaceable> is the number of seconds to
- wait before starting negotiations) can be used:</para>
-
- <programlisting xml:lang="en">set openmode active <replaceable>N</replaceable></programlisting>
-
- <para xml:lang="en">Check the manual page for details.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-shell-test-lockup">
- <para xml:lang="en">Why does <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> lock up when I shell out to test
- it?</para>
- </question>
-
- <answer>
- <para xml:lang="en">When using <command>shell</command> or
- <command>!</command>, <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> executes a shell
- or the passed arguments. The
- <application>ppp</application> program will wait for the
- command to complete before continuing. Any attempt to
- use the PPP link while running the command will appear as
- a frozen link. This is because <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> is
- waiting for the command to complete.</para>
-
- <para xml:lang="en">To execute commands like this, use
- <command>!bg</command> instead. This will execute the
- given command in the background, and <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> can
- continue to service the link.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-null-modem">
- <para xml:lang="en">Why does <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> over a null-modem cable never
- exit?</para>
- </question>
-
- <answer>
- <para xml:lang="en">There is no way for <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> to automatically
- determine that a direct connection has been dropped. This
- is due to the lines that are used in a null-modem serial
- cable. When using this sort of connection, LQR should
- always be enabled with the following line:</para>
-
- <programlisting xml:lang="en">enable lqr</programlisting>
-
- <para xml:lang="en">LQR is accepted by default if negotiated by the
- peer.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-auto-noreasondial">
- <para xml:lang="en">Why does <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> dial for no reason in
- <option>-auto</option> mode?</para>
- </question>
-
- <answer>
- <para xml:lang="en">If <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> is dialing unexpectedly,
- determine the cause, and set up dial filters to
- prevent such dialing.</para>
-
- <para xml:lang="en">To determine the cause, use the following line:</para>
-
- <programlisting xml:lang="en">set log +tcp/ip</programlisting>
-
- <para xml:lang="en">This will log all traffic through the connection. The
- next time the line comes up unexpectedly, the
- reason will be logged with a convenient timestamp next to
- it.</para>
-
- <para xml:lang="en">Next, disable dialing under these circumstances.
- Usually, this sort of problem arises due to DNS lookups.
- To prevent DNS lookups from establishing a connection
- (this will <emphasis>not</emphasis> prevent <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- from passing the packets through an established
- connection), use the following:</para>
-
- <programlisting xml:lang="en">set dfilter 1 deny udp src eq 53
-set dfilter 2 deny udp dst eq 53
-set dfilter 3 permit 0/0 0/0</programlisting>
-
- <para xml:lang="en">This is not always suitable, as it will effectively
- break demand-dial capabilities. Most programs
- will need a DNS lookup before doing any other network
- related things.</para>
-
- <para xml:lang="en">In the DNS case, try to determine what is actually
- trying to resolve a host name. A lot of the time,
- <application>Sendmail</application> is the culprit. Make
- sure to configure <application>Sendmail</application> not
- to do any DNS lookups in its configuration file. See the
- section on <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/smtp-dialup.html">using
- email with a dialup connection</link> in the FreeBSD
- Handbook for details. You may
- also want to add the following line to
- <filename>.mc</filename>:</para>
-
- <programlisting xml:lang="en">define(`confDELIVERY_MODE', `d')dnl</programlisting>
-
- <para xml:lang="en">This will make <application>Sendmail</application>
- queue everything until the queue is run, usually,
- every 30 minutes, or until a <command>sendmail
- -q</command> is done, perhaps from
- <filename>/etc/ppp/ppp.linkup</filename>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ccp-errors">
- <para xml:lang="en">What do these CCP errors mean?</para>
- </question>
-
- <answer>
- <para xml:lang="en">I keep seeing the following errors in my log
- file:</para>
-
- <programlisting xml:lang="en">CCP: CcpSendConfigReq
-CCP: Received Terminate Ack (1) state = Req-Sent (6)</programlisting>
-
- <para xml:lang="en">This is because <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> is trying to negotiate
- Predictor1 compression, but the peer does not want to
- negotiate any compression at all. The messages are
- harmless, but can be silenced by disabling the
- compression:</para>
-
- <programlisting xml:lang="en">disable pred1</programlisting>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-connectionspeed">
- <para xml:lang="en">Why does <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> not log my connection
- speed?</para>
- </question>
-
- <answer>
- <para xml:lang="en">To log all lines of the modem
- conversation, enable the
- following:</para>
-
- <programlisting xml:lang="en">set log +connect</programlisting>
-
- <para xml:lang="en">This will make <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> log everything up until the
- last requested <quote>expect</quote> string.</para>
-
- <para xml:lang="en">To see the connect speed when using
- PAP or CHAP,
- make sure to configure <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> to
- expect the whole CONNECT line, using something
- like this:</para>
-
- <programlisting xml:lang="en">set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 4 \
- \"\" ATZ OK-ATZ-OK ATDT\\T TIMEOUT 60 CONNECT \\c \\n"</programlisting>
-
- <para xml:lang="en">This gets the CONNECT, sends nothing, then expects a
- line-feed, forcing <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> to read the whole CONNECT
- response.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="ppp-ignores-backslash">
- <para xml:lang="en">Why does <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> ignore the <literal>\</literal>
- character in my chat script?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The <application>ppp</application> utility parses each
- line in its configuration files so that it can interpret
- strings such as <literal>set phone "123 456 789"</literal>
- correctly and realize that the number is actually only
- one argument. To specify a
- <literal>"</literal> character, escape it
- using a backslash (<literal>\</literal>).</para>
-
- <para xml:lang="en">When the chat interpreter parses each argument, it
- re-interprets the argument to find any special escape
- sequences such as <literal>\P</literal> or
- <literal>\T</literal>. As a result
- of this double-parsing, remember to use the
- correct number of escapes.</para>
-
- <para xml:lang="en">To actually send a <literal>\</literal>
- character, do something
- like:</para>
-
- <programlisting xml:lang="en">set dial "\"\" ATZ OK-ATZ-OK AT\\\\X OK"</programlisting>
-
- <para xml:lang="en">It will result in the following sequence:</para>
-
- <programlisting xml:lang="en">ATZ
-OK
-AT\X
-OK</programlisting>
-
- <para xml:lang="en">Or:</para>
-
- <programlisting xml:lang="en">set phone 1234567
-set dial "\"\" ATZ OK ATDT\\T"</programlisting>
-
- <para xml:lang="en">It will result in the following sequence:</para>
-
- <programlisting xml:lang="en">ATZ
-OK
-ATDT1234567</programlisting>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="fcs-errors">
- <para xml:lang="en">What are FCS errors?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FCS stands for Frame Check Sequence. Each PPP packet
- has a checksum attached to ensure that the data being
- received is the data being sent. If the FCS of an
- incoming packet is incorrect, the packet is dropped and
- the HDLC FCS count is increased. The HDLC error values
- can be displayed using the <literal>show hdlc</literal>
- command.</para>
-
- <para xml:lang="en">If the link is bad or if the serial driver is dropping
- packets, it will produce the occasional FCS error.
- This is not usually worth worrying about although it does
- slow down the compression protocols substantially.</para>
-
- <para xml:lang="en">If the link freezes as soon as it connects and
- produces a large number of FCS errors, make sure the modem
- is not using software flow control (XON/XOFF). If the
- link must use software flow control, use
- <literal>set accmap 0x000a0000</literal> to
- tell <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> to escape the <literal>^Q</literal> and
- <literal>^S</literal> characters.</para>
-
- <para xml:lang="en">Another reason for too many FCS errors may be
- that the remote end has stopped talking
- <acronym>PPP</acronym>. In this case, enable
- <literal>async</literal> logging to
- determine if the incoming data is actually a login or
- shell prompt. If it is a shell prompt at the remote
- end, it is possible to terminate <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> without
- dropping the line by using <command>close lcp</command>
- followed by <command>term</command>) to reconnect to
- the shell on the remote machine.</para>
-
- <para xml:lang="en">If nothing in the log file indicates why the link
- was terminated, ask the remote
- administrator or ISP why the session was
- terminated.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="desperation">
- <para xml:lang="en">None of this helps — I am desperate! What can I
- do?</para>
- </question>
-
- <answer>
- <para xml:lang="en">If all else fails, send the details of the error, the
- configuration files, how <citerefentry><refentrytitle>ppp</refentrytitle><manvolnum>8</manvolnum></citerefentry> is being started, the
- relevant parts of the log file, and the
- output of <command>netstat -rn</command>, before and after
- connecting, to the <link xlink:href="http://lists.FreeBSD.org/mailman/listinfo/freebsd-questions">FreeBSD general questions mailing list</link>.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="serial">
- <title xml:lang="en">Serial Communications</title>
-
- <para xml:lang="en">This section answers common questions about serial
- communications with FreeBSD. PPP is covered in the <link linkend="networking">Networking</link> section.</para>
-
- <qandaset>
- <qandaentry>
- <question xml:id="multiport-serial-support">
- <para xml:lang="en">Which multi-port serial cards are supported by
- FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">There is a list of these in the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/serial.html">Serial
- Communications</link> chapter of the Handbook.</para>
-
- <para xml:lang="en">Most multi-port PCI cards that are based on 16550 or
- clones are supported with no extra effort.</para>
-
- <para xml:lang="en">Some unnamed clone cards have also been known to work,
- especially those that claim to be AST compatible.</para>
-
- <para xml:lang="en">Check <citerefentry><refentrytitle>uart</refentrytitle><manvolnum>4</manvolnum></citerefentry> and <citerefentry><refentrytitle>sio</refentrytitle><manvolnum>4</manvolnum></citerefentry> to get more
- information on configuring such cards.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="serial-console-prompt">
- <para xml:lang="en">How do I get the boot: prompt to show on the serial
- console?</para>
- </question>
-
- <answer>
- <para xml:lang="en">See <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/serialconsole-setup.html">this
- section of the Handbook</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="found-serial">
- <para xml:lang="en">How do I tell if FreeBSD found my serial ports or modem
- cards?</para>
- </question>
-
- <answer>
- <para xml:lang="en">As the FreeBSD kernel boots, it will probe for the serial
- ports for which the kernel is configured.
- Either watch the boot messages closely
- or run this command after the system is up and
- running:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>grep -E '^(sio|uart)[0-9]' &lt; /var/run/dmesg.boot</userinput>
-sio0: &lt;16550A-compatible COM port&gt; port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0
-sio0: type 16550A
-sio1: &lt;16550A-compatible COM port&gt; port 0x2f8-0x2ff irq 3 on acpi0
-sio1: type 16550A</screen>
-
- <para xml:lang="en">This example shows two serial ports. The first is on
- IRQ4, port address
- <literal>0x3f8</literal>, and has a 16550A-type UART chip.
- The second uses the same kind of chip but is on
- IRQ3 and is at port address
- <literal>0x2f8</literal>. Internal modem cards are
- treated just like serial ports, except that they
- always have a modem attached to the
- port.</para>
-
- <para xml:lang="en">The <filename>GENERIC</filename> kernel includes
- support for two serial ports using the same IRQ and port
- address settings in the above example. If these settings
- are not right for the system, or if there are more modem
- cards or serial ports than the kernel is
- configured for, reconfigure using the instructions in
- <link linkend="make-kernel">building a kernel</link>
- for more details.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="access-serial-ports">
- <para xml:lang="en">How do I access the serial ports on FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The third serial port, <filename>sio2</filename>,
- or <filename>COM3</filename>,
- is on <filename>/dev/cuad2</filename> for dial-out
- devices, and on <filename>/dev/ttyd2</filename> for
- dial-in devices. What is the difference between these two
- classes of devices?</para>
-
- <para xml:lang="en">When
- opening <filename>/dev/ttydX</filename> in blocking mode,
- a process will wait for the corresponding
- <filename>cuadX</filename> device to become inactive, and
- then wait for the carrier detect line to go active. When
- the <filename>cuadX</filename> device is opened, it makes
- sure the serial port is not already in use by the
- <filename>ttydX</filename> device. If the port is
- available, it steals it from the
- <filename>ttydX</filename> device. Also, the
- <filename>cuadX</filename> device does not care about
- carrier detect. With this scheme and an auto-answer
- modem, remote users can log in and local users can still
- dial out with the same modem and the system will take care
- of all the conflicts.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="enable-multiport-serial">
- <para xml:lang="en">How do I enable support for a multi-port serial
- card?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The section on kernel configuration provides
- information about configuring the kernel. For a
- multi-port serial card, place an <citerefentry><refentrytitle>sio</refentrytitle><manvolnum>4</manvolnum></citerefentry> line for each
- serial port on the card in the <citerefentry vendor="current"><refentrytitle>device.hints</refentrytitle><manvolnum>5</manvolnum></citerefentry> file.
- But place the IRQ specifiers on only one of the entries.
- All of the ports on the card should share one IRQ. For
- consistency, use the last serial port to specify the IRQ.
- Also, specify the following option in the kernel
- configuration file:</para>
-
- <programlisting xml:lang="en">options COM_MULTIPORT</programlisting>
-
- <para xml:lang="en">The following <filename>/boot/device.hints</filename>
- example is for an AST 4-port serial card on
- IRQ 12:</para>
-
- <programlisting xml:lang="en">hint.sio.4.at="isa"
-hint.sio.4.port="0x2a0"
-hint.sio.4.flags="0x701"
-hint.sio.5.at="isa"
-hint.sio.5.port="0x2a8"
-hint.sio.5.flags="0x701"
-hint.sio.6.at="isa"
-hint.sio.6.port="0x2b0"
-hint.sio.6.flags="0x701"
-hint.sio.7.at="isa"
-hint.sio.7.port="0x2b8"
-hint.sio.7.flags="0x701"
-hint.sio.7.irq="12"</programlisting>
-
- <para xml:lang="en">The flags indicate that the master port has minor
- number <literal>7</literal> (<literal>0x700</literal>),
- and all the ports share an IRQ
- (<literal>0x001</literal>).</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="default-serial-params">
- <para xml:lang="en">Can I set the default serial parameters for a
- port?</para>
- </question>
-
- <answer>
- <para xml:lang="en">See the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/serial.html#serial-hw-config">Serial
- Communications</link> section in the FreeBSD
- Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="enable-dialup">
- <para xml:lang="en">How can I enable dialup logins on my modem?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Refer to the section about <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/dialup.html">Dial-in
- Services</link> in the FreeBSD Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="dumb-terminal">
- <para xml:lang="en">How can I connect a dumb terminal to my FreeBSD
- box?</para>
- </question>
-
- <answer>
- <para xml:lang="en">This information is in the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/term.html">Terminals</link>
- section of the FreeBSD Handbook.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="cannot-tip">
- <para xml:lang="en">Why can I not run <command>tip</command> or
- <command>cu</command>?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The built-in <citerefentry><refentrytitle>tip</refentrytitle><manvolnum>1</manvolnum></citerefentry> and
- <citerefentry><refentrytitle>cu</refentrytitle><manvolnum>1</manvolnum></citerefentry> utilities can only access the
- <filename>/var/spool/lock</filename> directory via user
- <systemitem class="username">uucp</systemitem> and group
- <systemitem class="groupname">dialer</systemitem>.
- Use the <systemitem class="groupname">dialer</systemitem> group to control
- who has access to the modem or remote systems by adding
- user accounts to <systemitem class="groupname">dialer</systemitem>.</para>
-
- <para xml:lang="en">Alternatively, everyone can be configured to run
- <citerefentry><refentrytitle>tip</refentrytitle><manvolnum>1</manvolnum></citerefentry> and <citerefentry><refentrytitle>cu</refentrytitle><manvolnum>1</manvolnum></citerefentry> by typing:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>chmod 4511 /usr/bin/cu</userinput>
-<prompt>#</prompt> <userinput>chmod 4511 /usr/bin/tip</userinput></screen>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="misc">
- <title xml:lang="en">Miscellaneous Questions</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="more-swap">
- <para xml:lang="en">FreeBSD uses a lot of swap space even when the computer
- has free memory left. Why?</para>
- </question>
-
- <answer>
- <para xml:lang="en">FreeBSD will proactively move entirely idle, unused pages
- of main memory into swap in order to make more main memory
- available for active use. This heavy use of swap is
- balanced by using the extra free memory for
- caching.</para>
-
- <para xml:lang="en">Note that while FreeBSD is proactive in this regard, it
- does not arbitrarily decide to swap pages when the system
- is truly idle. Thus, the system will not be all
- paged out after leaving it
- idle overnight.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="top-freemem">
- <para xml:lang="en">Why does <command>top</command> show very little free
- memory even when I have very few programs running?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The simple answer is that free memory is wasted
- memory. Any memory that programs do not actively
- allocate is used within the FreeBSD kernel as disk cache.
- The values shown by <citerefentry><refentrytitle>top</refentrytitle><manvolnum>1</manvolnum></citerefentry> labeled as
- <literal>Inact</literal> and <literal>Laundry</literal>
- are cached data at different
- aging levels. This cached data means the system does not
- have to access a slow disk again for data it has accessed
- recently, thus increasing overall performance. In
- general, a low value shown for <literal>Free</literal>
- memory in <citerefentry><refentrytitle>top</refentrytitle><manvolnum>1</manvolnum></citerefentry> is good, provided it is not
- <emphasis>very</emphasis> low.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="chmod-symlinks">
- <para xml:lang="en">Why will <command>chmod</command> not change the
- permissions on symlinks?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Symlinks do not have permissions, and by default,
- <citerefentry><refentrytitle>chmod</refentrytitle><manvolnum>1</manvolnum></citerefentry> will follow symlinks to change the
- permissions on the source file, if possible. For
- the file, <filename>foo</filename> with a symlink named
- <filename>bar</filename>, this command
- will always succeed.</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>chmod g-w bar</userinput></screen>
-
- <para xml:lang="en">However, the permissions on <filename>bar</filename>
- will not have changed.</para>
-
- <para xml:lang="en">When changing modes of the file hierarchies rooted in
- the files instead of the files themselves, use
- either <option>-H</option> or <option>-L</option> together
- with <option>-R</option> to make this work. See
- <citerefentry><refentrytitle>chmod</refentrytitle><manvolnum>1</manvolnum></citerefentry> and <citerefentry><refentrytitle>symlink</refentrytitle><manvolnum>7</manvolnum></citerefentry> for more
- information.</para>
-
- <warning>
- <para xml:lang="en"><option>-R</option> does a
- <emphasis>recursive</emphasis> <citerefentry><refentrytitle>chmod</refentrytitle><manvolnum>1</manvolnum></citerefentry>. Be
- careful about specifying directories or symlinks to
- directories to <citerefentry><refentrytitle>chmod</refentrytitle><manvolnum>1</manvolnum></citerefentry>. To change the
- permissions of a directory referenced by a symlink, use
- <citerefentry><refentrytitle>chmod</refentrytitle><manvolnum>1</manvolnum></citerefentry> without any options and follow the symlink
- with a trailing slash (<filename>/</filename>). For
- example, if <filename>foo</filename> is a symlink to
- directory <filename>bar</filename>, to
- change the permissions of <filename>foo</filename>
- (actually <filename>bar</filename>), do
- something like:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>chmod 555 foo/</userinput></screen>
-
- <para xml:lang="en">With the trailing slash, <citerefentry><refentrytitle>chmod</refentrytitle><manvolnum>1</manvolnum></citerefentry> will follow
- the symlink, <filename>foo</filename>, to change the
- permissions of the directory,
- <filename>bar</filename>.</para>
- </warning>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="dos-binaries">
- <para xml:lang="en">Can I run DOS binaries under FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Yes. A DOS emulation program,
- <package>emulators/doscmd</package>, is available in the
- FreeBSD Ports Collection.</para>
-
- <para xml:lang="en">If <application>doscmd</application> will not suffice,
- <package>emulators/pcemu</package>
- emulates an 8088 and enough BIOS services to run many DOS
- text-mode applications. It requires the X Window
- System.</para>
-
- <para xml:lang="en">The Ports Collection also has
- <package>emulators/dosbox</package>. The main focus of
- this application is emulating old DOS games using the
- local file system for files.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="translation">
- <para xml:lang="en">What do I need to do to translate a FreeBSD document into
- my native language?</para>
- </question>
-
- <answer>
- <para xml:lang="en">See the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/fdp-primer/translations.html">Translation
- <acronym>FAQ</acronym></link> in the FreeBSD Documentation
- Project Primer.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="freebsd-mail-bounces">
- <para xml:lang="en">Why does my email to any address at <systemitem class="fqdomainname">FreeBSD.org</systemitem>
- bounce?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The <systemitem class="fqdomainname">FreeBSD.org</systemitem> mail
- system implements some <application>Postfix</application>
- checks on incoming mail and rejects mail that is either
- from misconfigured relays or otherwise appears likely to
- be spam. Some of the specific requirements are:</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en">The IP address of the SMTP client must
- "reverse-resolve" to a forward confirmed
- hostname.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">The fully-qualified hostname given in the
- SMTP conversation (either HELO or EHLO) must resolve
- to the IP address of the client.</para>
- </listitem>
- </itemizedlist>
-
- <para xml:lang="en">Other advice to help mail reach its destination
- include:</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en">Mail should be sent in plain text, and messages
- sent to mailing lists should generally be no more than
- 200KB in length.</para>
- </listitem>
-
- <listitem>
- <para xml:lang="en">Avoid excessive cross posting. Choose
- <emphasis>one</emphasis> mailing list which seems most
- relevant and send it there.</para>
- </listitem>
- </itemizedlist>
-
- <para xml:lang="en">If you still have trouble with email infrastructure at
- <systemitem class="fqdomainname">FreeBSD.org</systemitem>,
- send a note with the details to
- <email>postmaster@freebsd.org</email>; Include a
- date/time interval so that logs may be reviewed —
- and note that we only keep one week's worth of mail logs.
- (Be sure to specify the time zone or offset from
- UTC.)</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="free-account">
- <para xml:lang="en">Where can I find a free FreeBSD account?</para>
- </question>
-
- <answer>
- <para xml:lang="en">While FreeBSD does not provide open access to any of
- their servers, others do provide open access <trademark class="registered">UNIX</trademark>
- systems. The charge varies and limited services may be
- available.</para>
-
- <para xml:lang="en"><link xlink:href="http://www.arbornet.org/">Arbornet,
- Inc</link>, also known as <emphasis>M-Net</emphasis>,
- has been providing open access to <trademark class="registered">UNIX</trademark> systems since
- 1983. Starting on an Altos running System III, the site
- switched to BSD/OS in 1991. In June of 2000, the site
- switched again to FreeBSD. <emphasis>M-Net</emphasis> can be
- accessed via <application>telnet</application> and
- <application>SSH</application> and provides basic access
- to the entire FreeBSD software suite. However, network
- access is limited to members and patrons who donate to the
- system, which is run as a non-profit organization.
- <emphasis>M-Net</emphasis> also provides an bulletin board
- system and interactive chat.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="daemon-name">
- <para xml:lang="en">What is the cute little red guy's name?</para>
- </question>
-
- <answer>
- <para xml:lang="en">He does not have one, and is just called <quote>the
- BSD daemon</quote>. If you insist upon using a name,
- call him <quote>beastie</quote>. Note that
- <quote>beastie</quote> is pronounced
- <quote>BSD</quote>.</para>
-
- <para xml:lang="en">More about the BSD daemon is available on his <link xlink:href="http://www.mckusick.com/beastie/index.html">home
- page</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="use-beastie">
- <para xml:lang="en">Can I use the BSD daemon image?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Perhaps. The BSD daemon is copyrighted by Marshall
- Kirk McKusick. Check his <link xlink:href="http://www.mckusick.com/beastie/mainpage/copyright.html">Statement
- on the Use of the BSD Daemon Figure</link> for detailed
- usage terms.</para>
-
- <para xml:lang="en">In summary, the image can be used in a tasteful
- manner, for personal use, so long as appropriate credit
- is given. Before using the logo commercially, contact
- Kirk McKusick <email>mckusick@FreeBSD.org</email> for permission. More details are
- available on the <link xlink:href="http://www.mckusick.com/beastie/index.html">BSD
- Daemon's home page</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="daemon-images">
- <para xml:lang="en">Do you have any BSD daemon images I could use?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Xfig and eps drawings are available under
- <filename>/usr/share/examples/BSD_daemon/</filename>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="glossary">
- <para xml:lang="en">I have seen an acronym or other term on the mailing
- lists and I do not understand what it means. Where should
- I look?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Refer to the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/handbook/freebsd-glossary.html">FreeBSD
- Glossary</link>.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="bikeshed-painting">
- <para xml:lang="en">Why should I care what color the bikeshed is?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The really, really short answer is that you should
- not. The somewhat longer answer is that just because you
- are capable of building a bikeshed does not mean you
- should stop others from building one just because you do
- not like the color they plan to paint it. This is a
- metaphor indicating that you need not argue about every
- little feature just because you know enough to do so.
- Some people have commented that the amount of noise
- generated by a change is inversely proportional to the
- complexity of the change.</para>
-
- <para xml:lang="en">The longer and more complete answer is that after a
- very long argument about whether <citerefentry><refentrytitle>sleep</refentrytitle><manvolnum>1</manvolnum></citerefentry> should take
- fractional second arguments, Poul-Henning Kamp <email>phk@FreeBSD.org</email> posted a long
- message entitled <quote><link xlink:href="http://www.bikeshed.com">A
- bike shed (any color will do) on greener
- grass...</link></quote>. The appropriate portions of
- that message are quoted below.</para>
-
- <blockquote>
- <attribution xml:lang="en">Poul-Henning Kamp <email>phk@FreeBSD.org</email> on <link xlink:href="http://lists.FreeBSD.org/mailman/listinfo/freebsd-hackers">freebsd-hackers</link>, October 2,
- 1999</attribution>
-
- <para xml:lang="en"><quote>What is it about this bike shed?</quote>
- Some of you have asked me.</para>
-
- <para xml:lang="en">It is a long story, or rather it is an old story,
- but it is quite short actually. C. Northcote Parkinson
- wrote a book in the early 1960s, called
- <quote>Parkinson's Law</quote>, which contains a lot of
- insight into the dynamics of management.</para>
-
- <para xml:lang="en"><emphasis>[snip a bit of commentary on the
- book]</emphasis></para>
-
- <para xml:lang="en">In the specific example involving the bike shed, the
- other vital component is an atomic power-plant, I guess
- that illustrates the age of the book.</para>
-
- <para xml:lang="en">Parkinson shows how you can go into the board of
- directors and get approval for building a multi-million
- or even billion dollar atomic power plant, but if you
- want to build a bike shed you will be tangled up in
- endless discussions.</para>
-
- <para xml:lang="en">Parkinson explains that this is because an atomic
- plant is so vast, so expensive and so complicated that
- people cannot grasp it, and rather than try, they fall
- back on the assumption that somebody else checked all
- the details before it got this far. Richard P. Feynmann
- gives a couple of interesting, and very much to the
- point, examples relating to Los Alamos in his
- books.</para>
-
- <para xml:lang="en">A bike shed on the other hand. Anyone can build one
- of those over a weekend, and still have time to watch
- the game on TV. So no matter how well prepared, no
- matter how reasonable you are with your proposal,
- somebody will seize the chance to show that he is doing
- his job, that he is paying attention, that he is
- <emphasis>here</emphasis>.</para>
-
- <para xml:lang="en">In Denmark we call it <quote>setting your
- fingerprint</quote>. It is about personal pride and
- prestige, it is about being able to point somewhere and
- say <quote>There! <emphasis>I</emphasis> did
- that.</quote> It is a strong trait in politicians, but
- present in most people given the chance. Just think
- about footsteps in wet cement.</para>
- </blockquote>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="funnies">
- <title xml:lang="en">The FreeBSD Funnies</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="very-very-cool">
- <para xml:lang="en">How cool is FreeBSD?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Q. Has anyone done any temperature testing while
- running FreeBSD? I know <trademark class="registered">Linux</trademark> runs cooler than DOS, but
- have never seen a mention of FreeBSD. It seems to run really
- hot.</para>
-
- <para xml:lang="en">A. No, but we have done numerous taste tests on
- blindfolded volunteers who have also had 250 micrograms of
- LSD-25 administered beforehand. 35% of the volunteers
- said that FreeBSD tasted sort of orange, whereas <trademark class="registered">Linux</trademark>
- tasted like purple haze. Neither group mentioned any
- significant variances in temperature. We eventually had
- to throw the results of this survey out entirely anyway
- when we found that too many volunteers were wandering out
- of the room during the tests, thus skewing the results.
- We think most of the volunteers are at Apple now, working
- on their new <quote>scratch and sniff</quote> GUI. It is
- a funny old business we are in!</para>
-
- <para xml:lang="en">Seriously, FreeBSD uses the <acronym>HLT</acronym> (halt)
- instruction when the system is idle thus lowering its
- energy consumption and therefore the heat it generates.
- Also if you have <acronym>ACPI</acronym> (Advanced
- Configuration and Power Interface) configured, then FreeBSD
- can also put the CPU into a low power mode.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="letmeoutofhere">
- <para xml:lang="en">Who is scratching in my memory banks??</para>
- </question>
-
- <answer>
- <para xml:lang="en">Q. Is there anything <quote>odd</quote> that FreeBSD
- does when compiling the kernel which would cause the
- memory to make a scratchy sound? When compiling (and for
- a brief moment after recognizing the floppy drive upon
- startup, as well), a strange scratchy sound emanates from
- what appears to be the memory banks.</para>
-
- <para xml:lang="en">A. Yes! You will see frequent references to
- <quote>daemons</quote> in the BSD documentation, and what
- most people do not know is that this refers to genuine,
- non-corporeal entities that now possess your computer.
- The scratchy sound coming from your memory is actually
- high-pitched whispering exchanged among the daemons as
- they best decide how to deal with various system
- administration tasks.</para>
-
- <para xml:lang="en">If the noise gets to you, a good <command>fdisk
- /mbr</command> from DOS will get rid of them, but do not
- be surprised if they react adversely and try to stop you.
- In fact, if at any point during the exercise you hear the
- satanic voice of Bill Gates coming from the built-in
- speaker, take off running and do not ever look back!
- Freed from the counterbalancing influence of the BSD
- daemons, the twin demons of DOS and <trademark class="registered">Windows</trademark> are often
- able to re-assert total control over your machine to the
- eternal damnation of your soul. Now that you know, given
- a choice you would probably prefer to get used to the
- scratchy noises, no?</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="changing-lightbulbs">
- <para xml:lang="en">How many FreeBSD hackers does it take to change a
- lightbulb?</para>
- </question>
-
- <answer>
- <para xml:lang="en">One thousand, one hundred and sixty-nine:</para>
-
- <para xml:lang="en">Twenty-three to complain to -CURRENT about the lights
- being out;</para>
-
- <para xml:lang="en">Four to claim that it is a configuration problem, and
- that such matters really belong on -questions;</para>
-
- <para xml:lang="en">Three to submit PRs about it, one of which is misfiled
- under doc and consists only of <quote>it's
- dark</quote>;</para>
-
- <para xml:lang="en">One to commit an untested lightbulb which breaks
- buildworld, then back it out five minutes later;</para>
-
- <para xml:lang="en">Eight to flame the PR originators for not including
- patches in their PRs;</para>
-
- <para xml:lang="en">Five to complain about buildworld being broken;</para>
-
- <para xml:lang="en">Thirty-one to answer that it works for them, and they
- must have updated at a bad time;</para>
-
- <para xml:lang="en">One to post a patch for a new lightbulb to
- -hackers;</para>
-
- <para xml:lang="en">One to complain that he had patches for this three
- years ago, but when he sent them to -CURRENT they were
- just ignored, and he has had bad experiences with the PR
- system; besides, the proposed new lightbulb is
- non-reflexive;</para>
-
- <para xml:lang="en">Thirty-seven to scream that lightbulbs do not belong
- in the base system, that committers have no right to do
- things like this without consulting the Community, and
- WHAT IS -CORE DOING ABOUT IT!?</para>
-
- <para xml:lang="en">Two hundred to complain about the color of the bicycle
- shed;</para>
-
- <para xml:lang="en">Three to point out that the patch breaks
- <citerefentry><refentrytitle>style</refentrytitle><manvolnum>9</manvolnum></citerefentry>;</para>
-
- <para xml:lang="en">Seventeen to complain that the proposed new lightbulb
- is under GPL;</para>
-
- <para xml:lang="en">Five hundred and eighty-six to engage in a flame war
- about the comparative advantages of the GPL, the BSD
- license, the MIT license, the NPL, and the personal
- hygiene of unnamed FSF founders;</para>
-
- <para xml:lang="en">Seven to move various portions of the thread to -chat
- and -advocacy;</para>
-
- <para xml:lang="en">One to commit the suggested lightbulb, even though it
- shines dimmer than the old one;</para>
-
- <para xml:lang="en">Two to back it out with a furious flame of a commit
- message, arguing that FreeBSD is better off in the dark than
- with a dim lightbulb;</para>
-
- <para xml:lang="en">Forty-six to argue vociferously about the backing out
- of the dim lightbulb and demanding a statement from
- -core;</para>
-
- <para xml:lang="en">Eleven to request a smaller lightbulb so it will fit
- their Tamagotchi if we ever decide to port FreeBSD to that
- platform;</para>
-
- <para xml:lang="en">Seventy-three to complain about the SNR on -hackers
- and -chat and unsubscribe in protest;</para>
-
- <para xml:lang="en">Thirteen to post <quote>unsubscribe</quote>,
- <quote>How do I unsubscribe?</quote>, or <quote>Please
- remove me from the list</quote>, followed by the usual
- footer;</para>
-
- <para xml:lang="en">One to commit a working lightbulb while everybody is
- too busy flaming everybody else to notice;</para>
-
- <para xml:lang="en">Thirty-one to point out that the new lightbulb would
- shine 0.364% brighter if compiled with TenDRA (although it
- will have to be reshaped into a cube), and that FreeBSD
- should therefore switch to TenDRA instead of GCC;</para>
-
- <para xml:lang="en">One to complain that the new lightbulb lacks
- fairings;</para>
-
- <para xml:lang="en">Nine (including the PR originators) to ask <quote>what
- is MFC?</quote>;</para>
-
- <para xml:lang="en">Fifty-seven to complain about the lights being out two
- weeks after the bulb has been changed.</para>
-
- <para xml:lang="en"><emphasis>Nik Clayton <email>nik@FreeBSD.org</email> adds:</emphasis></para>
-
- <para xml:lang="en"><emphasis>I was laughing quite hard at
- this.</emphasis></para>
-
- <para xml:lang="en"><emphasis>And then I thought, <quote>Hang on,
- shouldn't there be '1 to document it.' in that list
- somewhere?</quote></emphasis></para>
-
- <para xml:lang="en"><emphasis>And then I was enlightened
- :-)</emphasis></para>
-
- <para xml:lang="en"><emphasis>Thomas Abthorpe <email>tabthorpe@FreeBSD.org</email></emphasis> says:
- <quote>None, <emphasis>real</emphasis> FreeBSD hackers are
- not afraid of the dark!</quote></para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="dev-null">
- <para xml:lang="en">Where does data written to
- <filename>/dev/null</filename> go?</para>
- </question>
-
- <answer>
- <para xml:lang="en">It goes into a special data sink in the CPU where it
- is converted to heat which is vented through the heatsink
- / fan assembly. This is why CPU cooling is increasingly
- important; as people get used to faster processors, they
- become careless with their data and more and more of it
- ends up in <filename>/dev/null</filename>, overheating
- their CPUs. If you delete <filename>/dev/null</filename>
- (which effectively disables the CPU data sink) your CPU
- may run cooler but your system will quickly become
- constipated with all that excess data and start to behave
- erratically. If you have a fast network connection you
- can cool down your CPU by reading data out of
- <filename>/dev/random</filename> and sending it off
- somewhere; however you run the risk of overheating your
- network connection and <filename>/</filename> or angering
- your ISP, as most of the data will end up getting
- converted to heat by their equipment, but they generally
- have good cooling, so if you do not overdo it you should
- be OK.</para>
-
- <para xml:lang="en"><emphasis>Paul Robinson adds:</emphasis></para>
-
- <para xml:lang="en">There are other methods. As every good sysadmin
- knows, it is part of standard practice to send data to the
- screen of interesting variety to keep all the pixies that
- make up your picture happy. Screen pixies (commonly
- mis-typed or re-named as <quote>pixels</quote>) are
- categorized by the type of hat they wear (red, green or
- blue) and will hide or appear (thereby showing the color
- of their hat) whenever they receive a little piece of
- food. Video cards turn data into pixie-food, and then
- send them to the pixies — the more expensive the
- card, the better the food, so the better behaved the
- pixies are. They also need constant stimulation —
- this is why screen savers exist.</para>
-
- <para xml:lang="en">To take your suggestions further, you could just throw
- the random data to console, thereby letting the pixies
- consume it. This causes no heat to be produced at all,
- keeps the pixies happy and gets rid of your data quite
- quickly, even if it does make things look a bit messy on
- your screen.</para>
-
- <para xml:lang="en">Incidentally, as an ex-admin of a large ISP who
- experienced many problems attempting to maintain a stable
- temperature in a server room, I would strongly discourage
- people sending the data they do not want out to the
- network. The fairies who do the packet switching and
- routing get annoyed by it as well.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="punk-my-friend">
- <para xml:lang="en">My colleague sits at the computer too much, how
- can I prank her?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Install <package role="port">games/sl</package> and
- wait for her to mistype <userinput>sl</userinput> for
- <command>ls</command>.</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="advanced">
- <title xml:lang="en">Advanced Topics</title>
-
- <qandaset>
- <qandaentry>
- <question xml:id="learn-advanced">
- <para xml:lang="en">How can I learn more about FreeBSD's internals?</para>
- </question>
-
- <answer>
- <para xml:lang="en">See the <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/books/arch-handbook">FreeBSD
- Architecture Handbook</link>.</para>
-
- <para xml:lang="en">Additionally, much general <trademark class="registered">UNIX</trademark> knowledge is
- directly applicable to FreeBSD.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="how-to-contribute">
- <para xml:lang="en">How can I contribute to FreeBSD? What can I do to
- help?</para>
- </question>
-
- <answer>
- <para xml:lang="en">We accept all types of contributions: documentation,
- code, and even art. See the article on <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/articles/contributing/article.html">Contributing
- to FreeBSD</link> for specific advice on how to do
- this.</para>
-
- <para xml:lang="en">And thanks for the thought!</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="define-snap-release">
- <para xml:lang="en">What are snapshots and releases?</para>
- </question>
-
- <answer>
- <para xml:lang="en">There are currently 2 active/semi-active
- branches in the FreeBSD <link xlink:href="http://svnweb.FreeBSD.org/base/">Subversion
- Repository</link>. (Earlier branches are only changed
- very rarely, which is why there are only 2
- active branches of development):</para>
-
- <itemizedlist>
- <listitem>
- <para xml:lang="en"><symbol>stable/11/</symbol> AKA
- <emphasis>11-STABLE</emphasis></para>
- </listitem>
-
- <listitem>
- <para xml:lang="en"><symbol>stable/12/</symbol> AKA
- <emphasis>12-STABLE</emphasis></para>
- </listitem>
-
- <listitem>
- <para xml:lang="en"><symbol>head/</symbol> AKA
- <emphasis>-CURRENT</emphasis> AKA
- <emphasis>12-CURRENT</emphasis></para>
- </listitem>
- </itemizedlist>
-
- <para xml:lang="en"><literal>HEAD</literal> is not an actual branch tag.
- It is a symbolic constant for
- the current, non-branched development
- stream known as
- <emphasis>-CURRENT</emphasis>.</para>
-
- <para xml:lang="en">Right now, <emphasis>-CURRENT</emphasis> is the
- 13.<replaceable>X</replaceable> development stream; the <emphasis>12-STABLE</emphasis>
- branch, <symbol>stable/12/</symbol>, forked off from
- <emphasis>-CURRENT</emphasis> in December 2018 and the
- <emphasis>11-STABLE</emphasis> branch, <symbol>stable/11/</symbol>, forked off from
- <emphasis>-CURRENT</emphasis> in October 2016.</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="kernel-panic-troubleshooting">
- <para xml:lang="en">How can I make the most of the data I see when my
- kernel panics?</para>
- </question>
-
- <answer>
- <para xml:lang="en">Here is typical kernel panic:</para>
-
- <programlisting xml:lang="en">Fatal trap 12: page fault while in kernel mode
-fault virtual address = 0x40
-fault code = supervisor read, page not present
-instruction pointer = 0x8:0xf014a7e5
-stack pointer = 0x10:0xf4ed6f24
-frame pointer = 0x10:0xf4ed6f28
-code segment = base 0x0, limit 0xfffff, type 0x1b
- = DPL 0, pres 1, def32 1, gran 1
-processor eflags = interrupt enabled, resume, IOPL = 0
-current process = 80 (mount)
-interrupt mask =
-trap number = 12
-panic: page fault</programlisting>
-
- <para xml:lang="en">This message is not enough. While the instruction
- pointer value is important, it is also configuration
- dependent as it varies depending on the kernel image.
- If it is a <filename>GENERIC</filename> kernel
- image from one of the snapshots, it is possible for
- somebody else to track down the offending function, but
- for a custom kernel, only you can tell us where the fault
- occurred.</para>
-
- <para xml:lang="en">To proceed:</para>
-
- <procedure>
- <step>
- <para xml:lang="en">Write down the instruction pointer value. Note
- that the <literal>0x8:</literal> part at the beginning
- is not significant in this case: it is the
- <literal>0xf0xxxxxx</literal> part that we
- want.</para>
- </step>
-
- <step>
- <para xml:lang="en">When the system reboots, do the following:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>nm -n kernel.that.caused.the.panic | grep f0xxxxxx</userinput></screen>
-
- <para xml:lang="en">where <literal>f0xxxxxx</literal> is the
- instruction pointer value. The odds are you will not
- get an exact match since the symbols in the kernel
- symbol table are for the entry points of functions and
- the instruction pointer address will be somewhere
- inside a function, not at the start. If you do not
- get an exact match, omit the last digit from the
- instruction pointer value and try again:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>nm -n kernel.that.caused.the.panic | grep f0xxxxx</userinput></screen>
-
- <para xml:lang="en">If that does not yield any results, chop off
- another digit. Repeat until there is some sort of
- output. The result will be a possible list of
- functions which caused the panic. This is a less than
- exact mechanism for tracking down the point of
- failure, but it is better than nothing.</para>
- </step>
- </procedure>
-
- <para xml:lang="en">However, the best way to track down the cause of a
- panic is by capturing a crash dump, then using
- <citerefentry><refentrytitle>kgdb</refentrytitle><manvolnum>1</manvolnum></citerefentry> to generate a stack trace on the crash
- dump.</para>
-
- <para xml:lang="en">In any case, the method is this:</para>
-
- <procedure>
- <step>
- <para xml:lang="en">Make sure that the following line is included in
- the kernel configuration file:</para>
-
- <programlisting xml:lang="en">makeoptions DEBUG=-g # Build kernel with gdb(1) debug symbols</programlisting>
- </step>
-
- <step>
- <para xml:lang="en">Change to the <filename>/usr/src</filename>
- directory:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>cd /usr/src</userinput></screen>
- </step>
-
- <step>
- <para xml:lang="en">Compile the kernel:</para>
-
- <screen xml:lang="en"><prompt>#</prompt> <userinput>make buildkernel KERNCONF=<replaceable>MYKERNEL</replaceable></userinput></screen>
- </step>
-
- <step>
- <para xml:lang="en">Wait for <citerefentry><refentrytitle>make</refentrytitle><manvolnum>1</manvolnum></citerefentry> to finish compiling.</para>
- </step>
-
- <step>
- <screen xml:lang="en"><prompt>#</prompt> <userinput>make installkernel KERNCONF=MYKERNEL</userinput></screen>
- </step>
-
- <step>
- <para xml:lang="en">Reboot.</para>
- </step>
- </procedure>
-
- <note>
- <para xml:lang="en">If <varname>KERNCONF</varname> is not included,
- the <filename>GENERIC</filename> kernel will instead
- be built and installed.</para>
- </note>
-
- <para xml:lang="en">The <citerefentry><refentrytitle>make</refentrytitle><manvolnum>1</manvolnum></citerefentry> process will have built two kernels.
- <filename>/usr/obj/usr/src/sys/MYKERNEL/kernel</filename>
- and
- <filename>/usr/obj/usr/src/sys/MYKERNEL/kernel.debug</filename>.
- <filename>kernel</filename> was installed as
- <filename>/boot/kernel/kernel</filename>, while
- <filename>kernel.debug</filename> can be used as the
- source of debugging symbols for <citerefentry><refentrytitle>kgdb</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
-
- <para xml:lang="en">To capture a crash dump, edit
- <filename>/etc/rc.conf</filename> and set
- <literal>dumpdev</literal> to point to either the swap
- partition or <literal>AUTO</literal>. This will cause the
- <citerefentry><refentrytitle>rc</refentrytitle><manvolnum>8</manvolnum></citerefentry> scripts to use the <citerefentry><refentrytitle>dumpon</refentrytitle><manvolnum>8</manvolnum></citerefentry> command to
- enable crash dumps. This command can also be run
- manually. After a panic, the crash dump can be recovered
- using <citerefentry><refentrytitle>savecore</refentrytitle><manvolnum>8</manvolnum></citerefentry>; if <literal>dumpdev</literal> is
- set in <filename>/etc/rc.conf</filename>, the <citerefentry><refentrytitle>rc</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- scripts will run <citerefentry><refentrytitle>savecore</refentrytitle><manvolnum>8</manvolnum></citerefentry> automatically and put
- the crash dump in <filename>/var/crash</filename>.</para>
-
- <note>
- <para xml:lang="en">FreeBSD crash dumps are usually the same size as
- physical RAM. Therefore, make sure there is enough
- space in <filename>/var/crash</filename> to hold the
- dump. Alternatively, run <citerefentry><refentrytitle>savecore</refentrytitle><manvolnum>8</manvolnum></citerefentry> manually
- and have it recover the crash dump to another directory
- with more room. It is possible to limit the
- size of the crash dump by using <literal>options
- MAXMEM=N</literal> where
- <replaceable>N</replaceable> is the size of kernel's
- memory usage in KBs. For example, for 1 GB
- of RAM, limit the kernel's memory usage to
- 128 MB, so that the crash dump size
- will be 128 MB instead of 1 GB.</para>
- </note>
-
- <para xml:lang="en">Once the crash dump has been recovered , get a
- stack trace as follows:</para>
-
- <screen xml:lang="en"><prompt>%</prompt> <userinput>kgdb /usr/obj/usr/src/sys/MYKERNEL/kernel.debug /var/crash/vmcore.0</userinput>
-<prompt>(kgdb)</prompt> <userinput>backtrace</userinput></screen>
-
- <para xml:lang="en">Note that there may be several screens worth of
- information. Ideally, use <citerefentry><refentrytitle>script</refentrytitle><manvolnum>1</manvolnum></citerefentry> to
- capture all of them. Using the unstripped kernel image
- with all the debug symbols should show the exact line of
- kernel source code where the panic occurred. The stack
- trace is usually read from the bottom up to trace
- the exact sequence of events that lead to the crash.
- <citerefentry><refentrytitle>kgdb</refentrytitle><manvolnum>1</manvolnum></citerefentry> can also be used to print out the contents of
- various variables or structures to examine the system
- state at the time of the crash.</para>
-
- <tip>
- <para xml:lang="en">If a second computer is available, <citerefentry><refentrytitle>kgdb</refentrytitle><manvolnum>1</manvolnum></citerefentry> can
- be configured to do remote debugging, including setting
- breakpoints and single-stepping through the kernel
- code.</para>
- </tip>
-
- <note>
- <para xml:lang="en">If <literal>DDB</literal> is enabled and the
- kernel drops into the debugger, a panic
- and a crash dump can be forced by typing
- <literal>panic</literal> at the <literal>ddb</literal>
- prompt. It may stop in the debugger again during the
- panic phase. If it does, type
- <literal>continue</literal> and it will finish the crash
- dump.</para>
- </note>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="dlsym-failure">
- <para xml:lang="en">Why has <function>dlsym()</function> stopped working
- for ELF executables?</para>
- </question>
-
- <answer>
- <para xml:lang="en">The ELF toolchain does not, by default, make the
- symbols defined in an executable visible to the dynamic
- linker. Consequently <function>dlsym()</function>
- searches on handles obtained from calls to
- <function>dlopen(NULL, flags)</function> will fail to find
- such symbols.</para>
-
- <para xml:lang="en">To search, using
- <function>dlsym()</function>, for symbols present in the
- main executable of a process, link the
- executable using the <option>--export-dynamic</option>
- option to the ELF linker (<citerefentry><refentrytitle>ld</refentrytitle><manvolnum>1</manvolnum></citerefentry>).</para>
- </answer>
- </qandaentry>
-
- <qandaentry>
- <question xml:id="change-kernel-address-space">
- <para xml:lang="en">How can I increase or reduce the kernel address space
- on i386?</para>
- </question>
-
- <answer>
- <para xml:lang="en">By default, the kernel address space is 1 GB
- (2 GB for PAE) for i386. When running a
- network-intensive server or using
- ZFS, this will probably not be
- enough.</para>
-
- <para xml:lang="en">Add the following line to the kernel configuration
- file to increase available space and rebuild the
- kernel:</para>
-
- <programlisting xml:lang="en">options KVA_PAGES=<replaceable>N</replaceable></programlisting>
-
- <para xml:lang="en">To find the correct value of
- <replaceable>N</replaceable>, divide the desired address
- space size (in megabytes) by four. (For example, it is
- <literal>512</literal> for 2 GB.)</para>
- </answer>
- </qandaentry>
- </qandaset>
- </chapter>
-
- <chapter xml:id="acknowledgments">
- <title xml:lang="en">Acknowledgments</title>
-
- <para xml:lang="en">This innocent little Frequently Asked Questions document has
- been written, rewritten, edited, folded, spindled, mutilated,
- eviscerated, contemplated, discombobulated, cogitated,
- regurgitated, rebuilt, castigated, and reinvigorated over the
- last decade, by a cast of hundreds if not thousands.
- Repeatedly.</para>
-
- <para xml:lang="en">We wish to thank every one of the people responsible, and we
- encourage you to <link xlink:href="@@URL_RELPREFIX@@/doc/en_US.ISO8859-1/articles/contributing/article.html">join
- them</link> in making this <acronym>FAQ</acronym> even
- better.</para>
- </chapter>
-</book>