Date: Mon, 14 Jan 2002 13:26:40 -0800 From: "Kevin Oberman" <oberman@ptavv.es.net> To: Doug Poland <doug@polands.org> Cc: questions@freebsd.org Subject: Re: disklabel, two questions... Message-ID: <20020114212640.05B8A5D2F@ptavv.es.net> In-Reply-To: Your message of "Mon, 14 Jan 2002 14:53:45 CST." <20020114145345.A16937@polands.org>
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> Date: Mon, 14 Jan 2002 14:53:45 -0600 > From: Doug Poland <doug@polands.org> > Sender: owner-freebsd-questions@FreeBSD.ORG > > Hello, > > I have two questions about the output of the disklabel command > when issued on SCSI hard drives > > 1. Is the rpm: field accurate? I *think* I have a 7200 R.P.M. > drive that is reported as 3600. No. It is almost totally obsolete as it is not relevant to IDE/ATA or SCSI disks. It is only meaningful for these old drive types and always shows 3600 for IDE/ATA and SCSI disks. > 2. Can one calculate the usable, formatted (ufs) capacity of the drive > from the bytes/sector: sectors/track: tracks/cylinder: sectors/cylinder: > cylinders: sectors/unit: fields? Probably not because modern drives are addressed by logical block and not CHS. CHS is not valid because modern drives pack more sectors on the cylinders near the outside of the disk than it does on the inner tracks. This is all hidden by the LBA scheme. Some old, small disks really ARE addressable by CHS and you can do some calculations on these. R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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