Date: Mon, 10 Aug 2009 21:02:58 +0200 From: Erik Trulsson <ertr1013@student.uu.se> To: Dag-Erling =?iso-8859-1?Q?Sm=F8rgrav?= <des@des.no> Cc: "Julian H. Stacey" <jhs@berklix.com>, freebsd-hardware@FreeBSD.org, Alexander Motin <mav@FreeBSD.org>, freebsd-arch@FreeBSD.org Subject: Re: Do we still need ATA disk CHS addressing? Message-ID: <20090810190258.GA25641@owl.midgard.homeip.net> In-Reply-To: <86eirjbjl3.fsf@ds4.des.no> References: <200908101640.n7AGeYH0054650@fire.js.berklix.net> <86eirjbjl3.fsf@ds4.des.no>
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On Mon, Aug 10, 2009 at 08:38:16PM +0200, Dag-Erling Sm=F8rgrav wrote: > "Julian H. Stacey" <jhs@berklix.com> writes: > > Alexander Motin <mav@FreeBSD.org> writes: > > > Have anybody seen ATA drive without LBA support in last years? > > Yes >=20 > Have you really, or did you just assume that "old" means "no LBA"? >=20 > > I run 20+ assorted hosts from 4.11 to 7.2 Uni & Dual proc, i386 (real 3= 86!) > > to 686 & amd64 so I guess I'm=20 > > A) Pretty vulnerable to legacy scare. > > B) A litmus tesst for a wider community of others, some with older k= it,=20 > > not on lists or with bleeding edge latest hardware, but will=20 > > get hit when stuff eg HCS gets declared legacy=3Ddumped. >=20 > Do you seriously intend to run FreeBSD 9 on kit that is too old to > support LBA? We're talking early nineties here. CHS doesn't scale past > 504 MB, so any ATA disk larger than that must peforce support LBA. I > bought my first 1 GB drive (Connor CFP1080) in 1995. Actually I believe even the very first version of the ATA standard (long before support for LBA or any other modern features was added) could handle larger disks than 504MiB. I think the original limit of ATA was 2.1 GB.=20 The 504MiB limit was actually the intersection between the limits of the PC BIOS and the limits of the ATA standard. (ATA and the BIOS had different number of bits used to indicate each of cylinder, head and sector. When you took the lower number of bits for each you ended up with the 504MiB limit.) --=20 <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se
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