Date: Fri, 16 Jun 1995 07:19:25 -0600 From: aflundi@sandia.gov (Alan F Lundin) To: freebsd-hackers@freebsd.org Subject: Re: HD Geometry dirty trick Message-ID: <199506161319.HAA02057@sargon.mdl.sandia.gov> In-Reply-To: Bruce Evans <bde@zeta.org.au> "Re: HD Geometry dirty trick" (Jun 16, 1:38pm)
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On Jun 16, 1:38pm, Bruce Evans wrote: > Subject: Re: HD Geometry dirty trick > > >> I've found that using "basic" geometry of 1023/64/32 > >> for SCSI HD with 1Gb capacity and just adjusting the first > >> value for other capacities , one can get painless install . > >> Foe example , if you install 4Gb HDD - we multiply 1023 by 4 > >> and use 4092/64/32 Geometry. > >> For 300Mb SCSI disk we use (Int(1023/3.3))/64/32 and so on. > > >Fine for Adaptec controllers, not so fine for NCR controllers that > >like to tranlate >1G drives to xxxx/62/34, yes that is right 62/34! > > I.e., 64/32 geometry works if it was the correct (BIOS) geometry all > along. Otherwise, it is unlikely to work. What do you mean by "correct"? I have a Fujitsu M2624 with an Adaptec 1542B in my home machine and a Micropolis 2217 with a Buslogic Bt445S in my machine at work, and neither have real geometries even in the ball park of xxxx/64/32, yet xxxx/64/32 is what DOS fdisk gave and is the only geometry of the several "reality based geometries" I tried that "worked" with 2.0.5R. I also have a Maxtor 7120a IDE drive that did not suffer from the need for this trick. I presume this is because the CMOS contains the IDE geometry, but not the SCSI geometries. --alan
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