Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!ucsd!ucbvax!RELAY.NSWC.NAVY.MIL!kcables From: kcables@RELAY.NSWC.NAVY.MIL Newsgroups: comp.sys.sgi Subject: Multiple archives on one tape Message-ID: <9012030759.aa18247@VGR.BRL.MIL> Date: 3 Dec 90 13:03:08 GMT Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 40 Hi everyone. I'm trying to write a script to do incremental backups on an 8mm cartridge. What I'd like to do is create multiple archives on the same volume, i.e., start at the beginning of the cartridge for Monday's archive, append Tuesday's archive to Monday's, etc. The man page for tar says that the -r (no rewind) option only works for the 9 track tape, so I'm assuming I can't use tar for this purpose with an 8mm cartridge, or even if there is a way to use tar the SA book says it's unreliable. The System Admin class book, in the chapter "Backups", says that multiple archives are possible, and they recommend using bru (p. 15). Unfortunately, they don't explain the semantics. So then I tried bru, whose man page doesn't say anything about multiple archives, only multiple volumes. With bru you must specify one of the mode options, and the only one that instructs bru to actually write to the tape is -c ("create a new archive"). According to the man page, -c causes the writing to start at the first block, which I'm not sure means at the very first block of the cartridge, or at the beginning of the next full block (i.e., it skips any remainder of the current block). 'tape8' and 'tape8nr' are symbolic links to the cartridge tape drive. This is what I tried: find | bru -cvd -f /dev/tape8 - which works fine for the first archive. Then I tried: find | bru -cvd -f /dev/tape8nr - and it responded with bru: warning - assuming end of volume 1 (unknown size) bru: load volume 2 and enter device [default: /dev/tape8nr] >> What am I missing here? Thanks in advance. My address is kcables@relay.nswc.navy.mil