1995-01-25 09:18:56 +00:00
|
|
|
.Dd August 27, 1993
|
|
|
|
|
.Dt CH 4
|
|
|
|
|
.Os FreeBSD
|
|
|
|
|
.Sh NAME
|
|
|
|
|
.Nm ch
|
|
|
|
|
.Nd scsi media-changer (juke box) driver
|
|
|
|
|
.Sh SYNOPSIS
|
1995-03-01 22:32:38 +00:00
|
|
|
.Nm device ch
|
|
|
|
|
.Nm device ch1 target 4 lun 0
|
1995-01-25 09:18:56 +00:00
|
|
|
.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 separatly 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
|
1995-03-01 22:32:38 +00:00
|
|
|
driver.
|
|
|
|
|
In FreeBSD releases prior to 2.1, the first found will be attached as
|
1995-01-25 09:18:56 +00:00
|
|
|
.Em ch0
|
|
|
|
|
and the next,
|
|
|
|
|
.Em ch1
|
|
|
|
|
etc.
|
1995-03-01 22:32:38 +00:00
|
|
|
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.
|
1995-01-25 09:18:56 +00:00
|
|
|
.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 sd 4
|
|
|
|
|
.Xr st 4
|
|
|
|
|
.Xr cd 4
|
|
|
|
|
.Sh HISTORY
|
|
|
|
|
The
|
|
|
|
|
.Nm
|
|
|
|
|
driver appeared in 386BSD 0.1
|
|
|
|
|
|
