pt.4 revision 6894 
1.Dd March 2, 1995
2.Dt PT 4
3.Os FreeBSD
4.Sh NAME
5.Nm pt
6.Nd scsi processor type driver
7.Sh SYNOPSIS
8.Nm device pt0 at scbus?
9.Sh DESCRIPTION
10The
11.Xr pt
12driver provides support for a 
13SCSI processor type device.  These are usually scanners and other
14devices using the SCSI link as a communication interface with device
15specific commands embedded in the data stream.
16.Pp
17A scsi adapter must be separately configured into the system
18before this driver can be used.
19.Pp
20This device only supports
21.Xr read 2
22and
23.Xr write 2 ,
24and the general scsi ioctl calls.
25.Sh IOCTLS
26The 
27.Nm
28driver has no ioctls of it's own but rather acts as a medium for the
29generic 
30.Xr scsi 4
31ioctls. These are described in
32.Em sys/scsiio.h.
33.Sh FILES
34.Bl -tag -width /dev/pt -compact
35.It Pa /dev/pt[0-255]
36pt{x} is the  'xth' processor device.
37.El
38.Sh DIAGNOSTICS
39The
40.Em "at scbus?"
41is required in the config file for the configuration
42system to know this is a SCSI device and generate the appropriate
43tables.
44.Pp
45The 0 in 
46.Em pt0
47in the configuration is required.
48This is a bug in 
49.Xr config 8 .
50.Pp
51All
52.Xr scsi 4
53debug ioctls work on 
54.Nm
55devices.
56.Sh SEE ALSO
57.Xr sd 4
58.Xr st 4
59.Xr cd 4
60.Xr ch 4
61.Xr su 4
62.Xr scsi 4
63.Sh HISTORY
64The
65.Nm
66driver appeared in FreeBSD 2.1
67