In some desparate cases in the past, where some mung brain had data on Sony Video 8 tapes (!) I ended up mucking around with "mt blksize" and just using "cat" to try to grab the stuff off the tape without any blocking, crazy as that sounds, but that was also on SGI IRIX with Exabyte 820 "Eagle" drives. It was a pain, and there were loads of errors, but I got most of the data off the tapes.
--jonathan
Joshua Baker-LePain wrote:
On Thu, 11 Mar 2004 at 2:21pm, Jonathan Dill wrote
I would try "amrestore -c" to just dump the image off the tape, and then do the uncompress and extraction separately, but you will need enough disk space to do it. Worst case, you could try "amrestore -r" and use "dd bs=32k skip=1 if=dump-file" to skip over the header, and then pipe that to the uncompress and extract processes.
The current slow-running process is 'amrestore -r'. I'm guessing it's forcing the block size that's the culprit here -- the amrestore man page isn't quite clear, but it seems to say that if you don't specify -b, it'll default to 32k. I tried just 'dd if=/dev/nst1 of=img.raw' but it said "dd: reading `/dev/nst1': Cannot allocate memory". tapeinfo says this about blocksizes for the drive:
MinBlock:2 MaxBlock:16777215
Maybe I should try dd with bs=16M? But will that pad the output file with an unacceptable-to-tar chunk at the end since the tapefile is unlikely to be an exact multiple of 16M?
Thanks.