pt.4 revision 13479 
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.Cd device pt0 at scbus?
9.Sh DESCRIPTION
10The
11.Nm
12driver provides support for a 
13.Tn SCSI
14processor type device.  These are usually scanners and other
15devices using the
16.Tn SCSI
17link as a communication interface with device
18specific commands embedded in the data stream.
19.Pp
20A
21.Tn SCSI
22adapter must be separately configured into the system
23before this driver can be used.
24.Pp
25This device only supports
26.Xr read 2
27and
28.Xr write 2 ,
29and the generic
30.Tn SCSI
31.Xr ioctl 2
32calls.
33The
34.Sq Li at scbus?
35is required in the config file for the configuration
36system to know this is a SCSI device and generate the appropriate
37tables.
38.Pp
39The
40.Sq Li 0
41in 
42.Sq Li pt0
43in the configuration is required.
44This is a deficiency in 
45.Xr config 8 .
46.Sh IOCTLS
47The 
48.Nm
49driver has no
50.Fn ioctl
51commands of its own but rather acts as a medium for the
52generic 
53.Xr scsi 4
54commands. These are described in
55.Aq Pa sys/scsiio.h .
56All
57.Xr scsi 4
58debug ioctls work on 
59.Nm
60devices.
61.Sh FILES
62.Bl -tag -width /dev/ptQQQ -compact
63.It Pa /dev/pt Ns Ar N
64the
65.No Ar N Ns th processor device.
66.El
67.Sh SEE ALSO
68.Xr scsi 4
69.Sh HISTORY
70The
71.Nm
72driver appeared in 
73.Tn FreeBSD
742.1.
75