From owner-freebsd-questions Mon Jul 14 05:06:03 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id FAA16615 for questions-outgoing; Mon, 14 Jul 1997 05:06:03 -0700 (PDT) Received: from gatekeeper.barcode.co.il (gatekeeper.barcode.co.il [192.116.93.17]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id FAA16610 for ; Mon, 14 Jul 1997 05:05:57 -0700 (PDT) Received: (from smap@localhost) by gatekeeper.barcode.co.il (8.8.5/8.6.12) id PAA24578; Mon, 14 Jul 1997 15:02:53 +0300 (IDT) X-Authentication-Warning: gatekeeper.barcode.co.il: smap set sender to using -f Received: from localhost.barcode.co.il(127.0.0.1) by gatekeeper.barcode.co.il via smap (V1.3) id sma024571; Mon Jul 14 15:02:09 1997 Message-ID: <33CA1547.AD3@barcode.co.il> Date: Mon, 14 Jul 1997 15:02:15 +0300 From: Nadav Eiron X-Mailer: Mozilla 3.0 (X11; I; SunOS 5.5 sun4m) MIME-Version: 1.0 To: dmaddox@scsn.net CC: Wes Peters - Softweyr LLC , Nick Johnson , questions@FreeBSD.ORG Subject: Re: A few solutions References: <199707140404.WAA07219@xmission.xmission.com> <19970714072626.64852@scsn.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-questions@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk Donald J. Maddox wrote: > > On Sun, Jul 13, 1997 at 10:04:27PM -0600, Wes Peters - Softweyr LLC wrote: > > > > Parity RAM won't prevent errors from happening, it will just tell you > > when they do. The system will respond by rebooting, which really > > doesn't get you much. You probably just ended up with better (or faster) > > RAM than what you had before. > > > > High-end UNIX workstations are often equipped with ECC RAM, which can > > actually "fix" one-bit errors in memory accesses. This is yet another > > area in which garden-variety PCs don't stack up to workstations, either > > in performance or cost. ;^) > > > > Buy good quality RAM, parity or not, and be happy. > > Feel free to correct me if I'm mistaken here, but I believe that there is > no such thing as "ECC RAM". ECC is a function of the motherboard, no? If > your motherboard supports ECC _and_ you have parity RAM, you can use ECC. 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. Nadav