Manual Reference Pages - COPYTAPE (1)
copytape - duplicate magtapes
copytape duplicates magtapes. It is intended for duplication of
bootable or other non-file-structured (non-tar-structured)
magtapes on systems with only one tape drive.
copytape is blissfully ignorant of tape formats. It merely makes
a bit-for-bit copy of its input.
In normal use,
copytape would be run twice. First, a boot tape is copied to an
intermediate disk file. The file is in a special format that
preserves the record boundaries and tape marks. On the second
copytape reads this file and generates a new tape. The second step
may be repeated if multiple copies are required. The typical
process would look like this:
tutorial% copytape /dev/rmt8 tape.tmp
tutorial% copytape tape.tmp /dev/rmt8
tutorial% rm tape.tmp
copytape copies from the standard input to the standard output, unless
input and output arguments are provided. It will automatically
determine whether its input and output are physical tapes, or
data files. Data files are encoded in a special (human-readable)
copytape will automatically determine what sort of thing its input
and output are, a twin-drive system can duplicate a tape in
one pass. The command would be
tutorial% copytape /dev/rmt8 /dev/rmt9
Skip tape marks. The specified number of tape marks are skipped
on the input tape, before the copy begins. By default, nothing is
skipped, resulting in a copy of the complete input tape. Multiple
tar(1) and dump(1) archives on a single tape are normally
separated by a single tape mark. On ANSI or IBM labelled tapes,
each file has three associated tape marks. Count carefully.
Limit. Only nnn files (data followed by a tape mark), at most,
are copied. This can be used to terminate a copy early. If the
skip option is also specified, the files skipped do not count
against the limit.
From tape. The input is treated as though it were a physical
tape, even if it is a data file. This option can be used
to copy block-structured device files other than magtapes.
To tape. The output is treated as though it were a physical
tape, even if it is a data file. Normally, data files mark
physical tape blocks with a (human-readable) header describing
the block. If the -t option is used when the output is
actually a disk file, these headers will not be written.
This will extract all the information from the tape, but
copytape will not be able to duplicate the original tape based on
the resulting data file.
copytape does not normally produce any output on the control terminal.
The verbose option will identify the input and output files,
tell whether they are physical tapes or data files, and
announce the size of each block copied. This can produce
a lot of output on even relatively short tapes. It is
intended mostly for diagnostic work.
ansitape(1), dd(1), tar(1), mtio(4), copytape(5)
David S. Hayes, Site Manager, US Army Artificial Intelligence Center.
Originally developed September 1984 at Rensselaer Polytechnic Institute,
Troy, New York.
Revised July 1986. This software is in the public domain.
copytape treats two successive file marks as logical end-of-tape.
The intermediate data file can consume huge amounts of
disk space. A 2400-foot reel at 6250-bpi can burn 140 megabytes.
This is not strictly speaking a bug, but users should
be aware of the possibility. Check disk space with
df(1) before starting
copytape. Caveat Emptor!
A 256K buffer is used internally. This limits the maximum block
size of the input tape.
|--> ||COPYTAPE (1) ||25 June 1986 |
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