Date: Sat, 30 Nov 1996 17:40:37 -0500 From: Jeff Aitken <jaitken@dimension.net> To: "'questions@freebsd.org'" <questions@freebsd.org> Subject: HP T4000s tape drive Message-ID: <01BBDEE5.9AAD8240@floosie.aitken.com>
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Hello all, I recently purchased an HP T4000s "Colorado" SCSI-2 tape drive for use on a FreeBSD/NT box (FreeBSD-2.1.5-RELEASE, FWIW). This drive uses tapes which purport to back up 4/8GB (without/with compression). I found the following info in the hardware guide that came with the drive: Tape Format: QIC-3095 (Travan TR-4) # of tracks: 73 Bit density: 67733 I'm a little unsure just how I should invoke, e.g., dump(1) to have things work "optimally". If I specify no arguments at all, like this: dump 0uf /dev/nrst0 /home then I get nowhere near the advertised capacity (the tape "fills up" after only a few hundred MB's). So, I gather I need to specify the density and length of the tape (via the 'd' and 's' options, respectively). Is it as simple as: dump 0udsf 67733 740 /dev/nrst0 /home or not? I presume that the "bit density" the manual mentions is the bits per inch (BPI)? The tapes claim to be 740ft (225.6m) in length. Just for fun, I've experimented with a variety of different density/length values, none of which satisfy me (yet). Using the above-mentioned values doesn't even come close, so I've obviously missed something. After searching both the www.freebsd.org databases (WWW/Handbook and USENET archive) I could turn up only two references to this matter, neither of which was terribly specific. One person mentioned that they had a similar drive (Conner T4000) and that it worked well (it "ripped right along" was the comment). I figure I must be missing something, since my drive hardly "rips right along". I'm seeing between 100 and 300 KBps during backups, far from the advertised 514KBps (which, no doubt, only occurs under "optimal" circumstances, like when using the HP-provided software under an HP-supported platform :-) :-) I don't read -questions, so please CC me on any answer. Thanks! -- Jeff Aitken Dimension Enterprises
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