Tape operation on Solaris

Post #37,602 by broomberg 5/5/02 11:06:45 PM Reply	Tape operation on Solaris I want to construct by own header file for each tape, which should be rewritable without harming the rest of it. Is there anyway to reserve 10MB at the begginning of each tape, and do rewrites? When I try, I always end up destroying the the true data file, using various dd options such as conv=notrunc, etc.
Post #37,627 by boxley 5/6/02 11:58:27 AM Reply	Write a 10meg file to /dev/rmt write all your other files to /dev/nrmt(no rewind mag tape.) when you change the header just make sure that you use the rmt device and dont overwrite the boundary. thanx, bill TAM ARIS QUAM ARMIPOTENS
Post #37,684 by broomberg 5/6/02 6:40:54 PM Reply	I did. I think do a 1k file: dd if=y of=/dev/rmt/0n bs=1k dd if=data of=/dev/rmt/0n bs=32k mt -f /dev/rmt/0 rewind dd if=/dev/rmt/0n of=y2 bs=1k dd of=data.2 if=/dev/rmt/0n bs=32k mt -f /dev/rmt/0 rewind Works find, rereads the data as expected. dd if=n of=/dev/rmt/0n bs=1k mt -f /dev/rmt/0 rewind dd if=/dev/rmt/0n of=n2 bs=1k dd of=data.3 if=/dev/rmt/0n bs=32k 'n2' comes back, matching 'n', but data.3 fails since the EOT was set to be at the end of 'n'.
Post #37,701 by morganek 5/6/02 10:19:52 PM Reply	Couple of ideas 1. Hardware compression? I remember SunOS has numbers tacked-onto the dev names to control this, but I've seen inconsistency between the device numbers and whatever the lights on the drive say it's doing for compression. I trust the lights. Lights is all Spock had. 2. Rather than try to read your data file sequentially after reading the header file, have you tried walking the tape forward with "mt fsf" to see if you can get to the data file? I would try it before rewriting the header file first just to see if it does what you expect. -Mike

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