Date: Tue, 24 Jan 1995 22:37:31 +0300 (????) From: Dmitry Khrustalev <dima@sunny.bog.msu.su> To: Poul-Henning Kamp <phk@ref.tfs.com> Cc: Terry Lambert <terry@cs.weber.edu>, freebsd-hackers@freefall.cdrom.com Subject: Re: disklabel (1.1.5.1), partitions Message-ID: <Pine.SOL.3.91.950124222808.17078B-100000@sunny> In-Reply-To: <199501241823.KAA21387@ref.tfs.com>
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On Tue, 24 Jan 1995, Poul-Henning Kamp wrote: > > > > Not all SCSI devices are thus translated? > > > mostly they are, unless the "> 1GB" option is set. > > > > Sorry, this isn't really a valid reason for lying about the geometry > Hey terry, you lost the reason: A scsi-disk >HAS< no geometry we should > care about. It seems you are wrong: you can query scsi-2 disk for it's geometry. For details, see ftp://ftp.cdf.toronto.edu/pub/scsiinfo/scsiinfo-3.3.shar.gz dima. > > > > > Hold on! How about because the kernel should know the real BIOS apparent > > > > geometry for instead of making things up like that? > > > true, except we cannot trust this one anymore :-( Some IDE and SCSI > > > drivers get their "geometry" in CONFIG.SYS these days. > > > > Actually, most EIDE controllers get them from a modified system boot block > > installed by the OEM for the machine. Blowing the system boot block in > > that case really screws you up. > No, 540Mb and above seems to get it from various "disk-managers" loaded > in the config.sys with an increasingly annoying frequency. > > > I don't understand... what's wrong with: > > > > Geometry CCCC/HH/SS (Physical CCCC/HH/SS) > The Physical isn't true, It's two years since I saw anything which added > (multiplied actually) up to the number of sectors available. > The numbers are fiction, make belive, has no use, value or connection > with our use of the drive. > > > > Has nothing to do with it. If you pass some of the weird geometries to > > > newfs it will become very confused... 32/64 works sensibly most of the > > > time. > > > > This is a bug in newfs, like the one where it doesn't create a lost+found, > > not a reason to bogify other parts of the system to hack around it. > Not true. Newfs and UFS was optimized to know about disk-geometry. Since > most (95%) drives these days are zoned (variable sectors/track), this isn't > of any particular use. The existense of caches on the drives doesn't improve > it either. > All the geometry is really used for is to size the "cylinder"-groups. > > -- > Poul-Henning Kamp <phk@login.dknet.dk> > TRW Financial Systems, Inc. > FreeBSD has, until now, not one single time had an undetected error. :-) >
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