From owner-freebsd-hardware Sun Nov 5 15:20:10 1995 Return-Path: owner-hardware Received: (from root@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id PAA21416 for hardware-outgoing; Sun, 5 Nov 1995 15:20:10 -0800 Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by freefall.freebsd.org (8.6.12/8.6.6) with ESMTP id PAA21404 for ; Sun, 5 Nov 1995 15:20:03 -0800 Received: from msmith@localhost by genesis.atrad.adelaide.edu.au (8.6.9/8.6.9) id JAA28952; Mon, 6 Nov 1995 09:53:47 +1030 From: Michael Smith Message-Id: <199511052323.JAA28952@genesis.atrad.adelaide.edu.au> Subject: Re: Known working DAT drives To: mjdl@interlog.com Date: Mon, 6 Nov 1995 09:53:47 +1030 (CST) Cc: hardware@freebsd.org In-Reply-To: <199511031707.MAA01266@lotbiniere.interlog.com> from "Michel Joly de Lotbiniere" at Nov 3, 95 12:07:38 pm Content-Type: text Content-Length: 2551 Sender: owner-hardware@freebsd.org Precedence: bulk Michel Joly de Lotbiniere stands accused of saying: > I'm in the process of selecting some kind of reasonably priced SCSI-2 > backup drive for my 1GB disk (o.k., that's a bit of a joke); it seems > I have the choice of three different media for 1-2GB tape capacity: > 1/4 inch tape (QIC 1000,2000) e.g. Tandberg > Sony minitape (QIC3080) e.g. Conner, Tandberg > Low end DAT (1-2GB) e.g. HP, Conner DAT is the right place for price/performance. > Since these are expensive devices, reliability and lack of problems > over the long haul (e.g. alignment) are a major concern. Indeed; given that you're shopping for the long term, buy something that's a bit too big now, so you won't grow out of it. > I've seen earlier, lower capacity drives from Tandberg: really solid > construction, and the 1/4 inch tape mechanism seems relatively simple, > so probably reliable. Tandberg have an excellent name in the tape business, agreed. > I've not examined any of the other two types. DAT seems very attractive, > with low priced media, small media storage requirements, high backup > speeds, but I'm not sure of long term reliability, since this > technology is far more complex mechanically than any of the others (it > is, after all, an audio recording format). Also, given the fact that > DAT tapes have about 1/3 of their capacity taken up by ECC (versus less > than half that by other formats), what are people's experiences of > the "backup that failed to restore correctly" and similar disasters > with DAT? None; DAT is the way to go. As you've observed, the format was engineered to survive in the "professional audio" environment, so it's actually quite rugged and fault tolerant. Once you have a DAT drive that works, (I've heard nasty stories about the Conner units, but countless good ones about the WangDAT, HP and Sony ones) you're laughing. Don't buy a unit with hardware compression unless you're certain that you will be backing up easily-compressible data; I've found that compressing units actually run _slower_ than non-compressing ones if you feed them tough data, and gzip does a better job compaction-wise anyway. > Michel Joly de Lotbiniere -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] My car has "demand start" -Terry Lambert UNIX: live FreeBSD or die! [[