.\"	$Id: ssc.4,v 1.1 1997/12/29 21:07:10 brian Exp $
.\"
.\" Copyright (c) 1997 Brian Somers <brian@Awfulhak.org>
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.Dd December 29, 1997
.Dt SSC 4
.Os FreeBSD
.Sh NAME
.Nm ssc
.Nd The `super scsi' driver
.Sh SYNOPSIS
.Cd "pseudo-device ssc"
.Sh DESCRIPTION
The
.Nm
driver provides an access point into the SCSI driver code that can
be used when no SCSI devices have previously been detected.  This
is useful for systems that contain only external SCSI devices that
may be powered off at boot time.
.Pp
The
.Sq scsi user ,
or
.Xr su 4
pseudo-device is used by
.Nm ssc ,
and therefore must also be configured.
.Sh KERNEL CONFIGURATION
There are no configuration parameters for the ssc pseudo-device.
.Pp
.Sh IOCTLS
The 
.Nm
driver has a single
.Dv SCIOCADDR
ioctl of it's own.  This ioctl must be used after opening
.Pa /dev/ssc
and before issuing any other ioctl calls:
.Bd -literal -offset indent
.Fd #include <sys/scsiio.h>

.Ft int
.Fn ioctl "int fd" "SCIOCADDR" "struct scsi_addr *data"
.Ed
.Pp
.Ar Fd
refers to the descriptor returned by
.Xr open 2 ,
and
.Ar data
must have the
.Ar scbus ,
.Ar target
and
.Ar lun
fields set as required.  This ioctl may be used at will to change the
device to which subsequent ioctls affect.
.Pp
All other ioctls are passed directly to the
.Xr su 4
pseudo-device driver, using the Bus, Target and Lun that were set
with the last
.Dv SCIOCADDR
ioctl call.
.Sh FILES
.Bl -tag -width /dev/ssc -compact
.It Pa /dev/ssc
The device file used to access the
.Sq super scsi
driver.
.El
.Sh DIAGNOSTICS
If any ioctl is attempted before issuing a
.Dv SCIOCADDR
ioctl,
.Dv ENXIO
is returned.  Otherwise, the ioctl is passed directly to the
.Xr su 4
driver.
.Sh SEE ALSO
.Xr open 2 ,
.Xr su 4 ,
.Xr scsi 8
.Sh HISTORY
The
.Nm
driver originally appeared in FreeBSD 2.0.5.