.\" Copyright (c) 1995
.\"	Peter Dufault,  All rights reserved.
.\"
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.\" $FreeBSD: head/share/man/man4/pt.4 213573 2010-10-08 12:40:16Z uqs $
.\"
.Dd March 2, 1995
.Dt PT 4
.Os
.Sh NAME
.Nm pt
.Nd SCSI processor type driver
.Sh SYNOPSIS
.Cd device pt
.Sh DESCRIPTION
The
.Nm
driver provides support for a
.Tn SCSI
processor type device.
These are usually scanners and other devices using the
.Tn SCSI
link as a communication interface with device
specific commands embedded in the data stream.
.Pp
A
.Tn SCSI
adapter must be separately configured into the system
before this driver can be used.
.Pp
This device supports
.Xr read 2
and
.Xr write 2 ,
and the
.Xr ioctl 2
calls described below.
.Sh IOCTLS
The following
.Xr ioctl 2
calls are supported by the
.Nm
driver.
They are defined in the header file
.In sys/ptio.h .
.Bl -tag -width 012345678901234
.It PTIOCGETTIMEOUT
This ioctl allows userland applications to fetch the current
.Nm
driver read and write timeout.
The value returned is in seconds.
.It PTIOCSETTIMEOUT
This ioctl allows userland applications to set the current
.Nm
driver read and write timeouts.
The value should be in seconds.
.El
.Sh FILES
.Bl -tag -width /dev/ptQQQ -compact
.It Pa /dev/pt Ns Ar N
the
.Ar N Ns th processor device.
.El
.Sh SEE ALSO
.Xr cam 4
.Sh HISTORY
The
.Nm
driver appeared in
.Fx 2.1 .