TomRhodesWritten by File Systems File Systems Support File Systems File systems are an integral part of any operating system. They allow users to upload and store files, provide access to data, and make hard drives useful. Different operating systems differ in their native file system. Traditionally, the native &os; file system has been the Unix File System UFS which has been modernized as UFS2. Since &os; 7.0, the Z File System (ZFS) is also available as a native file system. See for more information. In addition to its native file systems, &os; supports a multitude of other file systems so that data from other operating systems can be accessed locally, such as data stored on locally attached USB storage devices, flash drives, and hard disks. This includes support for the &linux; Extended File System (EXT). There are different levels of &os; support for the various file systems. Some require a kernel module to be loaded and others may require a toolset to be installed. Some non-native file system support is full read-write while others are read-only. After reading this chapter, you will know: The difference between native and supported file systems. Which file systems are supported by &os;. How to enable, configure, access, and make use of non-native file systems. Before reading this chapter, you should: Understand &unix; and &os; basics. Be familiar with the basics of kernel configuration and compilation. Feel comfortable installing software in &os;. Have some familiarity with disks, storage, and device names in &os;. &os; provides built-in support for several &linux; file systems. This section demonstrates how to load support for and how to mount the supported &linux; file systems. Kernel support for ext2 file systems has been available since &os; 2.2. In &os; 8.x and earlier, the code is licensed under the GPL. Since &os; 9.0, the code has been rewritten and is now BSD licensed. The &man.ext2fs.5; driver allows the &os; kernel to both read and write to ext2 file systems. This driver can also be used to access ext3 and ext4 file systems. The &man.ext2fs.5; filesystem has full read and write support for ext4 as of &os; 12.0-RELEASE. Additionally, extended attributes and ACLs are also supported, while journalling and encryption are not. Starting with &os; 12.1-RELEASE, a DTrace provider will be available as well. Prior versions of &os; can access ext4 in read and write mode using sysutils/fusefs-ext2. To access an ext file system, first load the kernel loadable module: &prompt.root; kldload ext2fs Then, mount the ext volume by specifying its &os; partition name and an existing mount point. This example mounts /dev/ad1s1 on /mnt: &prompt.root; mount -t ext2fs /dev/ad1s1 /mnt