Mag Tape Duplication Problems

[russ]

After hearing me brag about how great unix "tools" are for doing just 
about everything, a friend of mine asked me to duplicate a reel of 
nine-track tape that was estimated to contain app. 60 megs of data.  

Although I only have one nine track drive, I do have a cartridge streamer 
(20 megs) so I naively assumed that I could read and write the contents of 
the nine-track in 20 meg segments to three separate cartridge tapes and 
then concatenate the three cartridge tapes back onto a new reel of 
nine-track tape.  I had figured that if 'dd' couldn't handle it, a 
simple-minded program (on the order of while getchar (putchar) would be 
able to do the job.  

Apart from my profound ignorance of whatever it is that passes for 
sentinel-like characters on tape devices, one of the things I didn't plan 
on was that the tape turned out to contain, not one big file, but rather a 
zillion or so small files that appear to range from two to seven blocks in 
length.  

I suppose I could repetitiously invoke 'dd' while keeping track of the 
total number of blocks, but I keep wondering what will happen if we get 
down to the end of a cartridge tape and then come across a five meg file.  

Any suggestions about how this thing could be handled "elegantly"?

-- 
Russell Lawrence, WP Group, POB 306, Metairie, LA 70004
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