Re:

> on Linux I could make a disk image of a tape using a command such as...
> 
> dd bs=265b if=/dev/st0 of=/tmp/tape.img

Note that the above would not make an image of the tape on any Unix/Linux
system.

It would, at best, be a linear copy of all the bytes from the first file
on the tape.  What's the difference?  Record sizes are lost.  You could
not recreate arbitrary tapes from such a dd output.  Only if the input
was fixed sized records (*and* you copied enough data per record :) could
you save and later recreate a tape with dd.

Now, going from tape to tape with dd is a different matter, because the
tape will preserve the record sizes ... if the tape drives are configured
correctly (i.e., to not pad out records).  And, of course, temporarily 
ignoring the "what if there is more than one file" question :)
And completely ignoring the "dd is ignorant of setmarks" problem.

If you want to copy arbitrary tapes to a disk image on a Unix/Linux system, 
for later writing to tape, feel free to contact us for a solution.

Stan


-- 
Stan Sieler
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www.allegro.com/sieler/wanted/index.html 

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