Tape trivia (was Re: SCO/mountain streamer)

[W.c. Rothanburg]

In article <6806 at spdcc.SPDCC.COM> rbraun at spdcc.COM (Rich Braun) writes:

   This is a related question, regarding cpio under SCO and AIX:

	   How do I read tapes across two machines with byte-swapped
	   architectures?

I've successfully done this with tapes only (not diskettes) between
ISC, and AIX.  With the CPIO files, you need to make the tape with
the -c option to make the tapes compatible.  The tar files should
work un-modified.

As far as diskettes, I've only been able to do it with DOS files.
I use vpix (faster than dossette or mounting the diskette) and 
copy the files to the diskette.  On the aix side, I just use dosread
and doswrite as necessary.  (I don't have a tape drive on my
home system, so I use this more...)

   Another question:  how do I write multiple cpio archives to a single
   tape?  My AIX system doesn't seem to have the no-rewind device defined
   (and I can't find this item in the documentation), and SCO Unix doesn't
   seem to provide decent end-of-tape error handling.  You have to tell
   cpio how large your tape is, in kilobytes, which won't work correctly if
   you try to write multiple archives to one tape.  Also, because there
   seems to be no way to "seek to the beginning of the current archive"--
   it seems you have to rewind the tape and skip over the archives, an
   exceptionally slow process--I'm beginning to believe that I ought to just
   punt the idea of storing more than one archive per tape.

On AIX, the no-rewind setting is /dev/rmt?.1.  Also, tctl (I beleive
is the name of the program) will allow you to perform tape functions,
including forward spacing files.  Look in the files reference or
infoexplorer for all of the /dev/rmt* options.  There are 4 per
density.

Bill

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