rogerj@batcomputer.tn.cornell.edu (Roger Jagoda) (07/16/90)
Folks, I have inherited a UNIX system (VAX/ULTRIX) with a SCSI Exabyte (OEM'd 3rd Party as usual) Tape unit. My question regards the parameters for the best "dump" command use. For example, we're using now: dump <level>usdf 4800 6666 /dev/nrmt1h <f. system> This assumes a density or 4800 and a tape length of 6666 feet which CAN't be correct. Something is wrong as we can't restore files either..:-( The tape unit responds with "not a dump tape, I/O error" So, the tapes are SONY 120Ps and the ExaByte manual says the drive is capable of writing "linear recording density = 43200 bits/inch" Now, isn't this the number we should use instead of 4800 (which sounds more like a guess from the old 1600 bpi tape reel days..)? As for feet of tape length, we have asked everyone including the mail order house where the tapes were bought, NO ONE seesm to know how many feet of tape come on a 120 tape! The actual model number of the tape is "P6-120MP" for "Metal Particle". If anyone knows how long these tapes are can they post an answer? Thanks. Actually, couldn't we just put a very large number for the lenght (like 100000)? That number is just so the tape doesn't run off the reel during the dump, right? Well, our dumps don't take up 2.2G so there's probably no danger of that. Should our dump command be more like: dump <level>udsf 43200 100000 /dev/nrmt1h <f.system> ? Thanks in advance for any pointers or comments! --Roger Jagoda --Cornell University -- ------------------------------------------------------------------------- Roger Jagoda -- My employers don't even like paying Cornell University me, let alone accept responsibility fqoj@cornella.cit.cornell.edu for anything I say or do! --
grr@cbmvax.commodore.com (George Robbins) (07/16/90)
In article <10544@batcomputer.tn.cornell.edu> rogerj@tcgould.tn.cornell.edu (Roger Jagoda) writes: > Folks, > > I have inherited a UNIX system (VAX/ULTRIX) with a SCSI Exabyte (OEM'd 3rd Party as usual) Tape unit. My question regards the parameters for the best "dump" > command use. For example, we're using now: > > dump <level>usdf 4800 6666 /dev/nrmt1h <f. system> > > ... Actually, couldn't we just put a > very large number for the lenght (like 100000)? That number is just > so the tape doesn't run off the reel during the dump, right? Well, our > dumps don't take up 2.2G so there's probably no danger of that. Yes, subject to the concern that you don't use such impressive numbers that internal computations overflow... I'd use something like sd 36000 6250, which comes to "10 - 3600 foot tapes @6250 bpi, each of which hold not quite 200 M-byte". Other people have their own favorite lucky numbers. Uh, none of this should have the least effect on whether or not the dumps are readable - I'd look elsewhere for that problem! -- George Robbins - now working for, uucp: {uunet|pyramid|rutgers}!cbmvax!grr but no way officially representing: domain: grr@cbmvax.commodore.com Commodore, Engineering Department phone: 215-431-9349 (only by moonlite)