Return to BSD News archive
Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.mel.connect.com.au!munnari.OZ.AU!spool.mu.edu!howland.reston.ans.net!newsfeed.internetmci.com!news.mathworks.com!fu-berlin.de!zrz.TU-Berlin.DE!isst.fhg.de!berlin.fhg.de!news.fhg.de!blackbush.xlink.net!isar.de!krabat!leo From: leo@krabat.marco.de (Matthias Pfaller) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Parity SIMMS really necessary? Message-ID: <4923@krabat.marco.de> Date: 6 Dec 95 12:03:10 GMT References: <49lbnr$4fq@interport.net> <49qabp$efi@zuul.nmti.com> <49spbi$1m8@sixpack.wustl.edu> Organization: marco GmbH, D-85221 Dachau Lines: 22 X-Newsreader: TIN [version 1.2 PL2] Matt Lundberg (ml@sixpack.wustl.edu) wrote: > As for using non-parity SIMMS, what does that extra bit give you > anyway? I agree that ECC is an advantage, but parity will only > inform you that you have a memory error, in most cases by locking > up the machine. This is no help. Now for the brain-dead pcs that might be true. On a pc all you get on a parity error is a NMI. On a real machine you would get an interrupt *and* you would be able to get the address of the offending memory location. In alot of cases that's enough to recover: (1) The address is user process code area -> page it in again (2) The address is user process data area (!modified) -> page it in again (3) The address is user process data area (modified) -> kill process (4) The address is in kernel area -> panic Of course you have to mark the offending page if the error is permanent. Are you still unconvinced that parity is a *good* thing to have? Matthias -- leo@dachau.marco.de in real life: Matthias Pfaller marco GmbH, 85221 Dachau, Germany tel: +49 8131 516142