Date: Tue, 25 Jun 1996 19:15:51 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: dgy@rtd.com (Don Yuniskis) Cc: msmith@atrad.adelaide.edu.au, hua@xenon.chromatic.com, dgy@rtd.com, jsigmon@www.hsc.wvu.edu, hackers@freebsd.org Subject: Re: Memory tests ... Message-ID: <199606250945.TAA29306@genesis.atrad.adelaide.edu.au> In-Reply-To: <199606250900.CAA01330@seagull.rtd.com> from "Don Yuniskis" at Jun 25, 96 02:00:04 am
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Don Yuniskis stands accused of saying: > > > > So if you just want a 'does it work, yes/no' answer, put the memory into > > your favorite high-performance OS (I prefer FreeBSD, OS/2 and Novell are > > also popular), and thrash it mercilessly for a few days. > > I don't see the value of this -- except for the fact that it's "easy" > to invoke from a shell :> If the system seizes up, it just tells > you something died (most probably memory). You are counting on the > failure to happen in such a way as to corrupt the state of the > processor irrevocably. Yup, and giving the system a hard workout leads to lots of page reusage and a fairly good chance of having most pages in the system exercised with code or critical data. > I find use of a LFSR with a long, "relatively prime" period to > alternately fill and check memory contents is great as a quick > POST-style check. It can also be used for more thorough testing > (i.e. to catch thermal problems) if set in an endless loop. And, > unlike just running a system hard for a while, it (usually) > survives a memory failure and can report on the failure. > > Of course, this *doesn't* test other hardware that may be marginal, > etc. (i.e. DMAC's). ... nor does it consider crosstalk, or parts with marginal timing characteristics that take a little too long to deliver the data if the rail sags or spikes at the wrong time, or... Yes, the 'thrash' test is primitive, but it's highly statistical by nature, and at the end of the day, the results are generally pretty good. > --don Rant rant rant 8) -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] Collector of old Unix hardware. "Where are your PEZ?" The Tick [[
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