*BSD News Article 56315


Return to BSD News archive

Newsgroups: comp.unix.bsd.freebsd.misc
Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.rmit.EDU.AU!news.unimelb.EDU.AU!munnari.OZ.AU!news.hawaii.edu!ames!usenet.kornet.nm.kr!usenet.hana.nm.kr!usenet.seri.re.kr!news.kreonet.re.kr!europa.chnt.gtegsc.com!news.msfc.nasa.gov!bcm.tmc.edu!cs.utexas.edu!howland.reston.ans.net!math.ohio-state.edu!news.physics.uiowa.edu!ljg
From: ljg@space.physics.uiowa.edu (Larry Granroth)
Subject: Re: Parity SIMMS really necessary?
X-Nntp-Posting-Host: ljgpc.physics.uiowa.edu
Message-ID: <DJ8wD5.4vA@sysadm.physics.uiowa.edu>
Sender: news@sysadm.physics.uiowa.edu (News Administrator)
Organization: The University of Iowa, Department of Physics and Astronomy
X-Newsreader: TIN [version 1.2 PL2]
References: <49lbnr$4fq@interport.net> <49qabp$efi@zuul.nmti.com> <4a2fug$b0u@cnn.nas.nasa.gov> <4a7kbb$8uj@overload.lbl.gov>
Date: Fri, 8 Dec 1995 02:03:04 GMT
Lines: 11

Any common commercial memory is susceptible to cosmic ray or other
statistical events that can flip a bit.  Given the small cross section
of the sensitive areas, this doesn't happen very often.  In my experience,
each of our Suns appear to experience isolated non-repeatable parity faults
about once every two or three years.  If your PC is rebooted a few times
a day, the importance of these errors is less than if you have a BSD
system that is up for months or years.  The bottom line is that if you
have an error, you don't want it to propagate, which is why parity
(or ECC) is necessary.

larry-granroth@uiowa.edu