From owner-freebsd-questions Fri Jul 2 10:25:55 1999 Delivered-To: freebsd-questions@freebsd.org Received: from ares.maths.adelaide.edu.au (Ares.maths.adelaide.edu.au [129.127.44.147]) by hub.freebsd.org (Postfix) with ESMTP id B7EC314C3E for ; Fri, 2 Jul 1999 10:25:51 -0700 (PDT) (envelope-from glewis@ares.maths.adelaide.edu.au) Received: (from glewis@localhost) by ares.maths.adelaide.edu.au (8.9.3/8.9.3) id CAA61497 for freebsd-questions@freebsd.org; Sat, 3 Jul 1999 02:56:57 +0930 (CST) (envelope-from glewis) From: Greg Lewis Message-Id: <199907021726.CAA61497@ares.maths.adelaide.edu.au> Subject: Density for tapes with dump To: freebsd-questions@freebsd.org Date: Sat, 3 Jul 1999 02:56:57 +0930 (CST) X-Mailer: ELM [version 2.4ME+ PL56 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Hi all, My home system is currently a 3.0-R beast which I'm wanting to upgrade to 3.2-R. Shouldn't be a problem, but I'd like to do a backup first. I have an atapi tape drive which detects as wdc1: unit 0 (atapi): , removable, accel, dma, iordis wst0: Drive empty, readonly, reverse, qfa, ecc, 512b wst0: Max speed=600Kb/s, Transfer limit=52 blocks, Buffer size=728 blocks (a Seagate TapeStor Travan TR-4 tape drive). Unfortunately the density seems incorrectly set as when I try to dump my file systems it clearly gets its calculations wrong: DUMP: estimated 3821513 tape blocks on 97.88 tape(s). These are 4GB tapes. I'd really like to have a hard drive that took 100 tapes to back up, but no such luck ;). "mt -f /dev/rwst0 status" tells me: Mode Density Blocksize bpi Compression Current: X3.22-1983 512 bytes 800 none ---------available modes--------- 0: 0x00 variable 0 none 1: 0x00 variable 0 none 2: 0x00 variable 0 none 3: 0x00 variable 0 none I'm sure the 800bpi number is wrong, and I know I can give the correct argument to dump with the -d option, but I've no idea how to calculate what it is. Is bpi bytes/inch or blocks/inch? I know the tapes are 740ft long, or thats what the manual for the drive tells me :). Any help appreciated, thanks. -- Greg Lewis glewis@trc.adelaide.edu.au Computing Officer +61 8 8303 3237 Teletraffic Research Centre To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message