Date: Sun, 4 Aug 1996 09:30:40 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: randy@zyzzyva.com (Randy Terbush) Cc: hardware@freebsd.org Subject: Re: Mapped geometry vs. Actual Message-ID: <199608040000.JAA06275@genesis.atrad.adelaide.edu.au> In-Reply-To: <199608031613.LAA05555@sierra.zyzzyva.com> from "Randy Terbush" at Aug 3, 96 11:13:19 am
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Randy Terbush stands accused of saying: > > I've long been an advocate of working out the true geometry > issues when setting up SCSI drives. > > Could someone comment on whether this is still (ever) considered > to be worth the frustration? Consider this : most modern disk drives use ZBR; ie. they use differing numbers of sectors for different areas of the disk, because the recording limitation is the flux density on the media, not the data rate off the platter. So your average drive may have 5 or more zones, each with a different number of sectors per cylinder. Which one is "correct"? > I had a recently frustrating experience with a 540M Quantum Fireball > that FreeBSD simply refused to accept my "true" drive geometry. > FreeBSD won and mapped to ???/32/64. FreeBSD's only interest in the disk geometry is to match whatever the BIOS thinks, so that it can correctly locate the beginning of its partition on the disk. Finito. -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] Collector of old Unix hardware. "Where are your PEZ?" The Tick [[
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