mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-15 10:17:20 +00:00
111 lines
3.3 KiB
Groff
111 lines
3.3 KiB
Groff
.\" $Id$
|
|
.\" Copyright (c) 1996
|
|
.\" Julian Elischer <julian@freebsd.org>. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\"
|
|
.\" 2. Redistributions in binary form 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.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.Dd August 27, 1993
|
|
.Dt CH 4
|
|
.Os FreeBSD
|
|
.Sh NAME
|
|
.Nm ch
|
|
.Nd scsi media-changer (juke box) driver
|
|
.Sh SYNOPSIS
|
|
.Cd device ch
|
|
.Cd device ch1 target 4 lun 0
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Xr ch
|
|
driver provides support for a
|
|
.Em scsi
|
|
juke box. It allows many slots of media to be multiplexed between a number
|
|
of drives.
|
|
.Pp
|
|
A scsi adapter must also be separately configured into the system
|
|
before a scsi changer can be configured.
|
|
.Pp
|
|
As the scsi adapter is probed during boot, the
|
|
.Em SCSI
|
|
bus is scanned for devices. Any devices found which answer as 'Changer'
|
|
type devices will be 'attached' to the
|
|
.Nm
|
|
driver.
|
|
In FreeBSD releases prior to 2.1, the first found will be attached as
|
|
.Em ch0
|
|
and the next,
|
|
.Em ch1
|
|
etc.
|
|
Beginning in 2.1 it is possible to specify what ch unit a device should
|
|
come on line as; refer to
|
|
.Xr scsi 4
|
|
for details on kernel configuration.
|
|
.Pp
|
|
|
|
.Sh KERNEL CONFIGURATION
|
|
In configuring, if an optional
|
|
.Ar count
|
|
is given in the specification, that number of scsi media changers
|
|
are configured; Most storage for them is allocated only when found
|
|
so a large number of configured devices is cheap. (once the first
|
|
has included the driver).
|
|
|
|
.Pp
|
|
.Sh IOCTLS
|
|
The following
|
|
.Xr ioctl 2
|
|
call applies to the changer. It is defined in
|
|
in the header file
|
|
.Em sys/chio.h.
|
|
|
|
.Bl -tag -width DIOCSDINFO
|
|
CHIOOP
|
|
This appears to be a 'do-everything' call.
|
|
.El
|
|
.Sh NOTES
|
|
The
|
|
.Nm
|
|
driver was added to the system by
|
|
Stefan Grefen (grefen@goofy.zdv.uni-mainz.de)
|
|
who apparently had such a device
|
|
however It appears as though no-one I have heard of has ever used this
|
|
driver. If you use it please let me know so I can test changes.
|
|
Stefan appears to have suffered net.death (or at least net.disconnection).
|
|
I (julian) have never used this device. If you do please re-write this
|
|
man page and send it to me..
|
|
|
|
.Sh FILES
|
|
.Bl -tag -width /dev/ch[0-9] -compact
|
|
.It Pa /dev/ch[0-9]
|
|
device entries
|
|
.El
|
|
.Sh DIAGNOSTICS
|
|
None.
|
|
.Sh SEE ALSO
|
|
.Xr cd 4 ,
|
|
.Xr sd 4 ,
|
|
.Xr st 4
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
driver appeared in 386BSD 0.1.
|