xref: /netbsd/bin/mt/mt.1 (revision c4a72b64) 
1.\"	$NetBSD: mt.1,v 1.30 2002/09/25 15:18:41 wiz Exp $
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3.\" Copyright (c) 1981, 1990, 1993
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34.\"	@(#)mt.1	8.1 (Berkeley) 6/6/93
35.\"
36.Dd June 6, 1993
37.Dt MT 1
38.Os
39.Sh NAME
40.Nm mt
41.Nd magnetic tape manipulation
42.Sh SYNOPSIS
43.Nm
44.Op Fl f Ar tapename
45.Ar command
46.Op Ar count
47.Sh DESCRIPTION
48The
49.Nm
50program is used to give commands to a magnetic tape drive.
51By default
52.Nm
53performs the requested operation once.
54Operations may be performed multiple times by specifying
55.Ar count  .
56.Pp
57Note
58that
59.Ar tapename
60must reference a raw (not block) tape device.
61If
62.Ar tapename
63is of the form
64.Qq host:tapename ,
65or
66.Qq user@host:tapename ,
67.Nm
68writes to the named tape device on the remote host using
69.Xr rmt 8 .
70.Pp
71The
72.Xr rmt 8
73process on the remote host is typically initiated via
74.Xr rsh 1 ,
75although an alternate method such as
76.Xr ssh 1
77can be specified via the
78.Ev RCMD_CMD
79environment variable.
80.Pp
81The available commands are listed below.
82Only as many characters as are required to uniquely identify a command
83need be specified.
84.Bl -tag -width "eof, weof"
85.It Cm asf
86Move forward
87.Ar count
88files from the beginning of the tape.
89This is accomplished by a rewind followed by fsf
90.Ar count .
91.It Cm eof , weof
92Write
93.Ar count
94end-of-file marks at the current position on the tape.
95.It Cm fsf
96Forward space
97.Ar count
98files.
99.It Cm fsr
100Forward space
101.Ar count
102records.
103.It Cm bsf
104Back space
105.Ar count
106files.
107.It Cm bsr
108Back space
109.Ar count
110records.
111.It Cm rewind
112Rewind the tape
113(Count is ignored).
114.It Cm offline , rewoffl
115Rewind the tape and place the tape unit off-line
116(Count is ignored).
117.It Cm status
118Print status information about the tape unit
119(Count is ignored).
120.It Cm retension
121Retensions the tape
122(Not all tape drives support this feature; count is ignored).
123.It Cm erase
124Erases the tape
125(Not all tape drives support this feature; count is ignored).
126.It Cm eew
127Enable or disabled early warning EOM behaviour.
128.Ar Count
129is set to nonzero to enable, zero to disable.
130.It Cm eom
131Forward space to the end of recorded media
132(Count is ignored).
133.It Cm blocksize , setblk
134Set the tape blocksize to
135.Ar count
136bytes.
137A
138.Ar count
139of zero sets variable blocksize.
140.It Cm density , setdensity
141Set the tape density code to
142.Ar count
143as specified in the
144.Tn SCSI-3
145specification.
146See the
147.Sx DENSITY CODES
148section for a list of codes for commonly used media types.
149.It Cm rdspos
150Read the logical block position of the tape
151(Not all tape drives support this feature; count is ignored).
152.It Cm rdhpos
153Read the hardware block position of the tape
154(Not all tape drives support this feature; count is ignored).
155.It Cm setspos
156Set the logical block position of the tape to
157.Ar count
158(not all tape drives support this feature).
159.It Cm sethpos
160Set the hardware block position of the tape to
161.Ar count
162(not all tape drives support this feature).
163.It Cm compress
164If
165.Ar count
166is zero, disable compression.
167Otherwise enable compression (not all tape drives support this feature).
168.El
169.Pp
170If a tape name is not specified, and the environment variable
171.Ev TAPE
172is not set, then
173.Nm
174uses the device
175.Pa /dev/nrst0 .
176.Sh EXIT STATUS
177.Nm
178returns a 0 exit status when the operation(s) were successful,
1791 if the command was unrecognized, and 2 if an operation failed.
180.Sh DENSITY CODES
181The SCSI-3 specification defines a number of density codes for
182various tape media, some of which are listed here.
183Note that many tape drive vendors also define model-specific codes.
184.Pp
185.Bl -column "Code" "Format" -compact
186.It Em "Code	Format"
187.It Li 0 Ta Device default
188.It Li 1 Ta 1/2" 800 bpi
189.It Li 2 Ta 1/2" 1600 bpi
190.It Li 3 Ta 1/2" 6250 bpi
191.It Li 4 Ta QIC-11
192.It Li 5 Ta QIC-24
193.It Li 15 Ta QIC-120
194.It Li 16 Ta QIC-150
195.It Li 17 Ta QIC-320/525
196.It Li 18 Ta QIC-1320/1350
197.It Li 19 Ta DDS
198.It Li 28 Ta QIC-385M
199.It Li 29 Ta QIC-410M
200.It Li 30 Ta QIC-1000C
201.It Li 31 Ta QIC-2100C
202.It Li 32 Ta QIC-6GB
203.It Li 33 Ta QIC-20GB
204.It Li 34 Ta QIC-2GB
205.It Li 35 Ta QIC-875M
206.It Li 36 Ta DDS-2
207.It Li 37 Ta DDS-3
208.It Li 38 Ta DDS-4
209.El
210.Sh ENVIRONMENT
211If the following environment variables exist, they are utilized by
212.Nm "" .
213.Bl -tag -width Fl
214.It Ev TAPE
215.Nm
216uses device filename given in the
217.Ev TAPE
218environment variable if the
219.Ar tapename
220argument is not given.
221.It Ev RCMD_CMD
222.Nm
223will use
224.Ev RCMD_CMD
225rather than
226.Pa /usr/bin/rsh
227to invoke
228.Xr rmt 8
229on a remote machine.
230The full path name must be specified.
231.El
232.Sh FILES
233.Bl -tag -width /dev/rst* -compact
234.It Pa /dev/rst*
235Raw
236.Tn SCSI
237tape device
238.It Pa /dev/rmt*
239Raw magnetic tape device
240.El
241.Sh SEE ALSO
242.Xr dd 1 ,
243.Xr ioctl 2 ,
244.Xr mtio 4 ,
245.Xr st 4 ,
246.Xr environ 7
247.Sh HISTORY
248The
249.Nm
250utility appeared in
251.Bx 4.3 .
252