The
ch
driver provides support for SCSI juke boxes.
It allows many slots of media to be multiplexed between a number of drives.
A SCSI adapter and a logical scsibus must also be separately configured
into the system before a SCSI changer can be configured.
As the SCSI adapter is probed during boot, the SCSI bus is scanned for devices.
Any devices found which answer as
"Changer"
type devices will be
“attached”
to the
ch
driver.
The first device found will be attached as
ch0
and the next
ch1,
etc.
It is also possible to specify what
ch
unit a device should come on-line as; refer to
scsi(4)
for details on kernel configuration.