Date: Mon, 14 Jul 1997 05:47:10 -0700 From: David Greenman <dg@root.com> To: Nadav Eiron <nadav@barcode.co.il> Cc: dmaddox@scsn.net, Wes Peters - Softweyr LLC <softweyr@xmission.com>, Nick Johnson <spatula@gulf.net>, questions@FreeBSD.ORG Subject: Re: A few solutions Message-ID: <199707141247.FAA06163@implode.root.com> In-Reply-To: Your message of "Mon, 14 Jul 1997 15:02:15 %2B0300." <33CA1547.AD3@barcode.co.il>
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>No. What you need is ECC motherboard and ECC RAM. To be able to correct >memeory errors you need more bits than what's available on a parity >SIMM. Some ECC implementation (the one I have in mind is the AlphaServer >1000, don't know if Pentium MBs have this too) use standard RAM, but in >greater quantity. The AlphaServer 1000 has banks of 5 standard SIMMs, >instead of the 4 that would otherwise be required for its 128 bit memory >bus. It uses the extra memory to implement ECC. Later models used 4 ECC >SIMMs instead. ECC for 64bit words requires 8 syndrome bits. Coincidently, that just happens to be the number of parity bits you'd have if you had byte parity SIMMs, so modern PC motherboards use the 8 parity bits to implement ECC and no special ECC SIMMs are required. -DG David Greenman Core-team/Principal Architect, The FreeBSD Project
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