Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!usc!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!gryphon!turnkey!jackv From: jackv@turnkey.gryphon.COM (Jack F. Vogel) Newsgroups: comp.unix.aix Subject: Re: Tape Drive Parms Message-ID: <6375@turnkey.gryphon.COM> Date: 26 Sep 89 20:31:53 GMT References: <1132@msa3b.UUCP> Reply-To: jackv@turnkey.gryphon.COM Organization: Turnkey Computer Consultants, Westchester, CA Lines: 35 In article <1132@msa3b.UUCP> kevin@msa3b.UUCP (Kevin P. Kleinfelter) writes: >Does anyone have the magic numbers for a 6157-002 tape drive? >I'm looking for the fun stuff that the backup command needs like >tracks, density, etc. I have looked in the AIX doc, which assumes that >your tape drive doc provides the info. I have looked in the tape >drive doc, which assumes you are running in a DOS environment, and >you have software which knows. >WHat are the numbers, and where are they documented (where did I fail >to look)? Kevin, the place you want to look I believe (the problem is that I have looked in the docs for the next release and not the AIXPS/2 manual) is the man page for backup itself. The trick is in the way in which the streaming drive writes to tape, it writes in a serpentine fashion on the 9 tracks. Therefore when you specify the length with the -s flag use the tape length multiplied by 9, i.e., 600*9 = 5400. Now on density I am not completely sure, the tapes I have say "12500 ftpi" and I am not sure if that is equivalent to bpi or not but as a test I would suggest setting -d 12500 and see how it works, basically these numbers are used by backup to calculate how much data it can write on a tape and not really anything to do with the hardware, so if you get a reasonable amount on the tape fine; otherwise it will get a hardware error before it finishes. If anyone out there thinks this is a braindead way for software to behave, and why it couldn't just rely on hardware in its operation, I agree wholeheartedly :-}!! Disclaimer: my opinions only! -- Jack F. Vogel jackv@seas.ucla.edu AIX Technical Support - or - Locus Computing Corp. jackv@ifs.umich.edu