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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!news.wildstar.net!news.ececs.uc.edu!news.kei.com!news.mathworks.com!hunter.premier.net!www.nntp.primenet.com!nntp.primenet.com!news1.best.com!nntp1.best.com!shellx.best.com!not-for-mail From: rcarter@best.com (Russell Carter) Newsgroups: comp.unix.bsd.freebsd.misc,comp.unix.bsd.bsdi.misc Subject: Re: Why one should buy parity memory for reliability? Date: 25 Sep 1996 08:49:56 -0700 Organization: BEST Internet Communications Lines: 30 Message-ID: <52bkb4$h0i@shellx.best.com> References: <32485B0D.41C6@austin.ibm.com> <52b1lk$ijl@hamilton.maths.tcd.ie> NNTP-Posting-Host: shellx.best.com Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:27965 comp.unix.bsd.bsdi.misc:4975 In article <52b1lk$ijl@hamilton.maths.tcd.ie>, David Malone <dwmalone@maths.tcd.ie> wrote: >Tushar Patel <tpatel@austin.ibm.com> writes: > >>There is a big difference in the price between the parity and non >>parity memory so I am trying to justify the parity memory purchase. > >I guess the big thing is that you will get definite failures, as >opposed to the machine running funny from time to time. Its always >such a pain if something works properly half the time. When your >machine crashes with a parity error at location blah, you know your >simm is probably at the end of its days. > > David. Right. The essential question is how much is your (or the person who has to care that the thing keeps running) time worth? With parity the system halts with an NMI message of some sort. Without it, it crashes, usually sporadically, often with different symptoms. Could it be a disk? Could it be a controller? Could it be that new kernel? It usually only takes about 8 hours to go down the list of possibilities. How often does it happen? I've seen 5 SIMM failures in about 4 years of running upto 20 PCs full time. Not very often, but often enough so that the last several GB of memory I've installed all had parity. Cheers, Russell