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The
utility is used to give commands to a magnetic tape drive. By default
performs the requested operation once. Operations may be performed multiple
times by specifying Note that must reference a raw (not block) tape device.
The available commands are listed below. Only as many characters as are
required to uniquely identify a command need be specified. Write end-of-file
marks at the current position on the tape. Write setmarks at the current
position on the tape. Forward space files. Forward space records. Forward
space setmarks. Backward space files. Backward space records. Backward
space setmarks. Read Hardware block position. Some drives do not support
this. The block number reported is specific for that hardware only. The count
argument is ignored. Read SCSI logical block position. Some drives do not
support this. The count argument is ignored. Set Hardware block position.
Some drives do not support this. The count argument is interpreted as a
hardware block to which to position the tape. Set SCSI logical block position.
Some drives do not support this. The count argument is interpreted as a
SCSI logical block to which to position the tape. Rewind the tape (Count
is ignored). Rewind the tape and place the tape unit off-line (Count is
ignored). Erase the tape. A count of 0 disables long erase, which is on
by default. Re-tension the tape (one full wind forth and back, Count is
ignored). Print status information about the tape unit. For SCSI magnetic
tape devices, the current operating modes of density, blocksize, and whether
compression is enabled is reported. The current state of the driver (what
it thinks that it is doing with the device) is reported. If the driver knows
the relative position from BOT (in terms of filemarks and records), it
prints that. Note that this information is not definitive (only BOT, End
of Recorded Media, and hardware or SCSI logical block position (if the
drive supports such) are considered definitive tape positions). Print (and
clear) error status information about this device. For every normal operation
(e.g., a read or a write) and every control operation (e.g,, a rewind), the
driver stores up the last command executed and it’s associated status and
any residual counts (if any). This command retrieves and prints this information.
If possible, this also clears any latched error information. Set the block
size for the tape unit. Zero means variable-length blocks. Set the density
for the tape unit. For the density codes, see below. The density value could
be given either numerically, or as a string, corresponding to the field.
If the string is abbreviated, it will be resolved in the order shown in
the table, and the first matching entry will be used. If the given string
and the resulting canonical density name do not match exactly, an informational
message is printed about what the given string has been taken for. Fetch
and print out the current EOT filemark model. The model states how many
filemarks will be written at close if a tape was being written. Set (from
the argument) and print out the current and EOT filemark model. Typically
this will be filemarks, but some devices (typically QIC cartridge drives)
can only write filemark. Currently you can only choose a value of or
Forward space to end of recorded medium (Count is ignored). Forward space
to end of data, identical to Set compression mode. There are currently
several possible values for the compression mode: Turn compression off.
Turn compression on. Same as Same as IBM Improved Data Recording Capability
compression (0x10). DCLZ compression algorithm (0x20). In addition to
the above recognized compression keywords, the user can supply a numeric
compression algorithm for the tape drive to use. In most cases, simply turning
the compression will have the desired effect of enabling the default compression
algorithm supported by the drive. If this is not the case (see the display
to see which compression algorithm is currently in use), the user can manually
specify one of the supported compression keywords (above), or supply a
numeric compression value. If a tape name is not specified, and the environment
variable does not exist; uses the device The utility returns a 0 exit
status when the operation(s) were successful, 1 if the command was unrecognized,
and 2 if an operation failed. The following density table was taken from
the table (A-1) in Revision 11 of the SCSI-3 Stream Device Commands (SSC)
working draft, dated November 11, 1997. The different density codes are
as follows: Value Width Tracks Density Code Type
Reference Note mm in bpmm bpi
0x01 12.7 (0.5) 9 32 (800) NRZI R X3.22-1983 2 0x02
12.7 (0.5) 9 63 (1,600) PE R X3.39-1986 2 0x03 12.7
(0.5) 9 246 (6,250) GCR R X3.54-1986 2 0x05 6.3 (0.25)
4/9 315 (8,000) GCR C X3.136-1986 1 0x06 12.7 (0.5) 9
126 (3,200) PE R X3.157-1987 2 0x07 6.3 (0.25) 4
252 (6,400) IMFM C X3.116-1986 1 0x08 3.81 (0.15) 4 315
(8,000) GCR CS X3.158-1987 1 0x09 12.7 (0.5) 18 1,491 (37,871)
GCR C X3.180 2 0x0A 12.7 (0.5) 22 262 (6,667) MFM
C X3B5/86-199 1 0x0B 6.3 (0.25) 4 63 (1,600) PE C
X3.56-1986 1 0x0C 12.7 (0.5) 24 500 (12,690) GCR C HI-TC1
1,6 0x0D 12.7 (0.5) 24 999 (25,380) GCR C HI-TC2
1,6 0x0F 6.3 (0.25) 15 394 (10,000) GCR C QIC-120
1,6 0x10 6.3 (0.25) 18 394 (10,000) GCR C QIC-150
1,6 0x11 6.3 (0.25) 26 630 (16,000) GCR C QIC-320
1,6 0x12 6.3 (0.25) 30 2,034 (51,667) RLL C QIC-1350
1,6 0x13 3.81 (0.15) 1 2,400 (61,000) DDS CS X3B5/88-185A
5 0x14 8.0 (0.315) 1 1,703 (43,245) RLL CS X3.202-1991 5 0x15
8.0 (0.315) 1 1,789 (45,434) RLL CS ECMA TC17 5 0x16
12.7 (0.5) 48 394 (10,000) MFM C X3.193-1990 1 0x17 12.7
(0.5) 48 1,673 (42,500) MFM C X3B5/91-174 1 0x18 12.7 (0.5)
112 1,673 (42,500) MFM C X3B5/92-50 1 0x19 12.7 (0.5) 128
2,460 (62,500) RLL C DLTapeIII 6,7 0x1A 12.7 (0.5) 128
3,214 (81,633) RLL C DLTapeIV(20) 6,7 0x1B 12.7 (0.5) 208
3,383 (85,937) RLL C DLTapeIV(35) 6,7 0x1C 6.3 (0.25) 34
1,654 (42,000) MFM C QIC-385M 1,6 0x1D 6.3 (0.25) 32
1,512 (38,400) GCR C QIC-410M 1,6 0x1E 6.3 (0.25) 30
1,385 (36,000) GCR C QIC-1000C 1,6 0x1F 6.3 (0.25) 30
2,666 (67,733) RLL C QIC-2100C 1,6 0x20 6.3 (0.25) 144
2,666 (67,733) RLL C QIC-6GB(M) 1,6 0x21 6.3 (0.25) 144
2,666 (67,733) RLL C QIC-20GB(C) 1,6 0x22 6.3 (0.25) 42 1,600
(40,640) GCR C QIC-2GB(C) ? 0x23 6.3 (0.25) 38 2,666 (67,733)
RLL C QIC-875M ? 0x24 3.81 (0.15) 1 2,400 (61,000)
CS DDS-2 5 0x25 3.81 (0.15) 1 3,816 (97,000)
CS DDS-3 5 0x26 3.81 (0.15) 1 3,816 (97,000) CS
DDS-4 5 0x27 8.0 (0.315) 1 3,056 (77,611) RLL CS Mammoth
5 0x28 12.7 (0.5) 36 1,491 (37,871) GCR C X3.224
1 0x29 12.7 (0.5) 0x2A 0x2B 12.7 (0.5) 3 ? ?
? C X3.267 5 0x41 12.7 (0.5) 208 3,868 (98,250) RLL
C DLTapeIV(40) 6,7 0x48 12.7 (0.5) 448 5,236 (133,000) PRML
C SDLTapeI(110) 6,8 0x49 12.7 (0.5) 448 7,598 (193,000) PRML
C SDLTapeI(160) 6,8 Code Description
Type Description ---------------- ---------------- NRZI Non return
to zero, change on ones R Reel-to-reel GCR Group code recording
C Cartridge PE Phase encoded
CS Cassette IMFM Inverted modified frequency modulation
MFM Modified frequency modulation DDS DAT data storage RLL
Run length limited PRML Partial Response Maximum Likelihood NOTES
1. Serial recorded. 2. Parallel recorded. 3. Old format known as QIC-11. 5. Helical
scan. 6. This is not an American National Standard. The reference is based
on an industry standard definition of the media format.
7. DLT recording: serially recorded track pairs (DLTapeIII and DLTapeIV(20)),
or track quads (DLTapeIV(35) and DLTapeIV(40)).
8. Super DLT (SDLT) recording: 56 serially recorded logical tracks with
8 physical tracks each.
If the following environment variable exists, it is utilized
by The utility checks the environment variable if the argument is
not given.
QIC-02/QIC-36 magnetic tape interface SCSI magnetic tape
interface
The command appeared in Extensions regarding
the driver appeared in as a separate command, and have been merged into
the command in The former command that used to be a synonym for has
been abandoned in since it was often confused with which is fairly dangerous.
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