June 10, 1998 CH 4

### NAME

ch - SCSI media changer driver

### SYNOPSIS

ch* at scsibus? target ? lun ?

### DESCRIPTION

The ch driver is essentially an ioctl(2) interface to a robot on a SCSI bus - a device that will change media (e.g. tapes, CD-ROMs, etc) in and out of drives for that media. The chio(1) utility program uses this interface to manipulate such robots.

### FILES

```/dev/ch`u
  SCSI bus media changer unit u

```/usr/include/sys/chio.h`

### DIAGNOSTICS

ch%d: waiting %d seconds for changer to settle...
  Some changers require a long time to settle out, to do tape inventory, for instance.

ch%d: offline
  The changer is not responding.

ch%d: warning, READ ELEMENT STATUS avail != count

ch%d: could not sense element address page

ch%d: could not sense capabilities page

### SEE ALSO

chio(1), ioctl(2), cd(4), intro(4), scsi(4), st(4)

### AUTHORS

Jason R. Thorpe