PT(4)

NAME
pt - SCSI processor type driver

SYNOPSIS
device pt0 at scbus?

DESCRIPTION
The pt driver provides support for a SCSI processor type device. These are usually scanners and other devices using the SCSI link as a communication interface with device specific commands embedded in the data stream.

A SCSI adapter must be separately configured into the system before this driver can be used.

This device only supports read(2) and write(2), and the generic SCSI ioctl(2) calls. The ‘at scbus?’ is required in the config file for the configuration system to know this is a SCSI device and generate the appropriate tables.

The ‘0’ in ‘pt0’ in the configuration is required. This is a deficiency in config(8).

IOCTLS
The pt driver has no ioctl() commands of its own but rather acts as a medium for the generic scsi(4) commands. These are described in <sys/scsiio.h>. All scsi(4) debug ioctls work on pt devices.

FILES
/dev/ptN
    the Nth processor device.

SEE ALSO
scsi(4)

HISTORY
The pt driver appeared in FreeBSD 2.1.