Date: Thu, 16 Dec 1999 19:53:21 +0200 From: Ruslan Ermilov <ru@ucb.crimea.ua> To: Jonathon McKitrick <jcm@dogma.freebsd-uk.eu.org> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: LBA speed enhancements Message-ID: <19991216195321.A12391@relay.ucb.crimea.ua> In-Reply-To: <Pine.BSF.4.21.9912161648580.1526-100000@dogma.freebsd-uk.eu.org>; from Jonathon McKitrick on Thu, Dec 16, 1999 at 04:49:45PM %2B0000 References: <Pine.BSF.4.21.9912161648580.1526-100000@dogma.freebsd-uk.eu.org>
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On Thu, Dec 16, 1999 at 04:49:45PM +0000, Jonathon McKitrick wrote: > > In the LINT file, there are HD flags for LBA. Is this a performance > issue, or just to allow reading large drives? > This flag is to turn on logical block addressing mode on your drive. For example, one of my IDE drives becomes different with and without LBA. In CHS mode, BIOS reports 3298*16*63=3324384 geometry, and FreeBSD detects 3324384 sectors total. In LBA mode, BIOS reports 824*64*63=3322368 geometry, but FreeBSD detects 3324996 sectors!!! As you can see, using LBA mode gives me 612 "additional" sectors. Note, that you could turn on LBA mode only for "unformatted" drives, without existing filesystems. Changing the drive's current mode will certainly mess it up. Cheers, -- Ruslan Ermilov Sysadmin and DBA of the ru@ucb.crimea.ua United Commercial Bank, ru@FreeBSD.org FreeBSD committer, +380.652.247.647 Simferopol, Ukraine http://www.FreeBSD.org The Power To Serve http://www.oracle.com Enabling The Information Age To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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