Sun TAR

[Lawrence F. Strickland]

>From article <25434 at cca.CCA.COM>, by g-rh at cca.CCA.COM (Richard Harter):
> In article <327 at earth.atexrd.UUCP> mikeh at atexrd.UUCP (Mike Harris) writes:
>>Forgive me if this question has already been posed to the group, but can
>>anyone tell me how to extract from a tape, written by a MASSCOMP, from a
>>SUN??  I had have no trouble whatsoever reading and writing tapes between
>>Masscomp and Intel machines, but am unable to read the tape on a SUN.
>>Any Ideas?
> 
> Me thinks you are talking about 1/4 inch cartridge tapes rather than 1/2
> inch 9 track tapes.  1/2 inch 9 track TAR tapes all use the same format
> (excepting for delightful little bits like word order and BSD/Sys V block
> size differences).  They go all over the place.  Cartridges are a different
> matter -- there are several different formats in use in the industry and
> SUN follows their own drummer.  Someone have conversion software -- our
> experience is that life is a lot simpler if you stick to 9-track tape for
> inter machine transport.
> -- 

It is correct that there are numerous varieties of formats used by 1/4"
cartridge tapes.  In fact, AT&T cartridge tapes cannot be read/written by
anyone else in the known universe (this is the variety made by ctc routines.
Rumor has it there is another variety, but I can't find it).  However, I
don't believe this is the problem here.  Or at least not the major problem.

The original poster mentions that Intel machines could read/write the tape.
If these are XENIX machines with a standard drive, then the problem could
be the driver that is being used.  For tar tapes, it is common to use:

	$ tar xvf /dev/rst0

or the equivalent for creating the tape.  There is also a /dev/nrst0 which
is the non-rewinding version of the SCSI-tape driver.  It can be used for
multiple-file tapes (SUN does this on their boot tapes, though I always have
problems with it).

If you look in the /dev directory, you will also find a /dev/rst8 and a
/dev/nrst8.  By using:

	$ tar xvf /dev/rst8

I have been able to read tapes created on a number of different machines,
mostly XENIX, and write tapes that could be read on a XENIX machine.  I'm
not sure what the difference between the two drivers is, though.  Someone
once described it as a different 'density' (like mag tapes), but I doubt it.

If someone could shed more light on this, I'd love to know...

-larry
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