Date: Thu, 23 Nov 1995 02:16:13 +0000 () From: Michael Smith <msmith@atrad.adelaide.edu.au> To: terry@lambert.org (Terry Lambert) Cc: msmith@atrad.adelaide.edu.au, hasty@rah.star-gate.com, hackers@FreeBSD.org Subject: Re: Help! I got a bad block.... Message-ID: <199511230216.CAA27652@genesis.atrad.adelaide.edu.au> In-Reply-To: <199511222017.NAA06631@phaeton.artisoft.com> from "Terry Lambert" at Nov 22, 95 01:17:44 pm
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Terry Lambert stands accused of saying: > > and set AWRE and ARRE to enable reallocation on both read and write. > > Many drives ship with this off. > > I've always wondered about this. Join the club 8) > If the area is reserved anyway, then why ever ship with it off? Speed. Reliability - on a bad day, you may accidentally use half of the reallocation area remapping sectors that aren't really bad. Some drives (Quantum, fe.) don't support the SCSI Format command, and some do but insist on keeping their remapping information, so you may not be able to recover the unnecessarily replaced sectors. > If the area isn't reserved, then exactly what lossage should I expect > to see when enabling it? The area(s) are reserved. Some drives put them at the end of the disk, others band them across the disk to reduce the performance hit. > If the replacement sectors are otherwise exposed as usable data sectors, > turning it on would be Bad(tm) if you have already stored data on the > drive. I don't _think_ anyone would be that stupid. > If the replacement sectors are not otherwise exposed as usable data > sectors, having it off at all is silly. See above. Your point is arguably valid. > Terry Lambert -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 041-122-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] "Who does BSD?" "We do Chucky, we do." [[
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