Date: Sat, 15 Apr 1995 10:38:41 -0700 (PDT) From: Poul-Henning Kamp <phk@ref.tfs.com> To: uhclem@nemesis.lonestar.org (Frank Durda IV) Cc: freebsd-current@FreeBSD.org, uhclem@nemesis.lonestar.org Subject: Re: Memory init pattern Message-ID: <199504151738.KAA21617@ref.tfs.com> In-Reply-To: <m0s09Wp-0004vsC@nemesis.lonestar.org> from "Frank Durda IV" at Apr 15, 95 10:12:00 am
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> It is a good idea to at least initialize all of RAM that we plan to use > but I would pick a less annoying pattern. (Naturally there is some > low memory info like the CMOS size compute and other goodies that we should > utilize before we lay-waste to the below-640K areas, or perhaps we could > limit the re-write to above memory 1Meg, as that is where most of the > bad-inits usually occur.) > > Also, any pattern written must be unique across adjacent two 32-bit > values. In other words, don't write 0x12345678 and in the next 32 bits > write 0x12345678. You are setting yourself up for ghosting in 64/32-bit > system. You wouldn't believe how long it took to prove to SCO this was > happening on a 32/16 bit system, and we had the logic analyzer! > (If you want details on how this happens, send mail. I've written a few > dozen memory diags over the years.) :-( Hmm, how about writing one more ? -- Poul-Henning Kamp <phk@login.dknet.dk> -- TRW Financial Systems, Inc. 'All relevant people are pertinent' && 'All rude people are impertinent' => 'no rude people are relevant'
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