SUMMARY - reading old 1/2 inch tapes

From: Dennis Martens (MARTENSD@health.qld.gov.au)
Date: Mon Apr 06 1998 - 20:47:08 CDT


Thanks to Ian Parkin, who suggested tcopy. It was a good idea which
didn't work directly, but led me to a solution.
Also to:
Art Freeman, James Brigman, Jim Roy and Karl Vogel.

Still strange. tcopy reported that there were 3 x 80-byte records on the
tape.

I used: dd if=/dev/nrst1 of=file1 conv=ascii,notrunc,noerror and I
extracted what seemed to be a tape header.

I used tcopy again at this point but it said that the EOT had been
reached.

But when I eventually tried the dd command as above, but added bs=13200,
many records were extracted. Smaller block sizes were useless (nothing
extracted) and larger ones work as well. I guess knowing how the data
was recorded is crucial - and we didn't know it.

I don't know why tcopy couldn't see that there were more records on the
tape, and I don't know why the default block size wasn't enough to read
all the data. But I can read *some* data off the tapes, so I'm thankful.

Doc



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