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 general scsi ioctl calls.

IOCTLS
The pt driver has no ioctls of it's own but rather acts as a medium for the generic scsi(4) ioctls. These are described in sys/scsiio.h.

FILES
/dev/pt[0-255]
    pt{x} is the 'xth' processor device.

DIAGNOSTICS
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 bug in config(8).

All scsi(4) debug ioctls work on pt devices.

SEE ALSO
sd(4) st(4) cd(4) ch(4) su(4) scsi(4)

HISTORY
The pt driver appeared in FreeBSD 2.1