*BSD News Article 18792


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Path: sserve!newshost.anu.edu.au!munnari.oz.au!ariel.ucs.unimelb.EDU.AU!ucsvc.ucs.unimelb.edu.au!emu.insted.unimelb.edu.au!s345002
Newsgroups: comp.os.386bsd.misc
Subject: Re: External Cache diagnostics
Message-ID: <1993Jul26.003225.1@emu.insted.unimelb.edu.au>
From: s345002@emu.insted.unimelb.edu.au
Date: 26 Jul 93 00:32:25 EST
References: <22pmv7$b80@europa.eng.gtefsd.com> <michaelv.743538616@ponderous.cc.iastate.edu>
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In article <michaelv.743538616@ponderous.cc.iastate.edu>, michaelv@iastate.edu (Michael L. VanLoon) writes:
> In <22pmv7$b80@europa.eng.gtefsd.com> niemidc@oasis.gtefsd.com (David C. Niemi) writes:
> 
> 
>>I have had some problems with the 256KB external cache in my 486 DX/33.
>>I think it is working now, but I'd like to verify that 256 KB of cache
>>is indeed active.
> 
>>Has anyone heard of any utilities, UNIX or DOS or otherwise, that look
>>at and/or test the external cache?
> 
> MFT (manifest), the diagnostic utility that comes with QEMM will test
> your processor cache.

he just asked for a test for EXTERNAL cache ... not processor [internal] cache.

the concept of testing cache memory is quite interesting, because it is
designed to be seemless between the processor and any onboard memory.

to address your problems:

1. verifying you have 256KB external cache - does your BIOS tell you that
you have 256KB external cache? If it doesn't, you'll have to grab out the
motherboard manual and check the jumpers and associated onboard CACHE & TAG
RAM.

2. verifying that the external cache is active - if you can disable your
external cache from your BIOS setup then you can 'feel' the difference or
use a program like MIPS by Chips & Technology (1986) which includes a
processor to memory speed test.

3. verifying that the cache is alive and well - use a memory checking
program like that in QAPlus or Checkit Pro. do an INTENSIVE TEST and let
it cycle for say, 24 hours. usually dud cache ram will show problems up
in about 2 to 3 hours.

dud cache is sometimes very hard to trace and play with - usually because
your vendor will never acknowledge the existance of such a problem. 
I have seen very few motherboards with dud cache ram as a one-off problem.
I have seen many motherboards with dud cache ram as part of a dud shipment.

-ah

> 
> 
> 
> -- 
> ------------------------------------------------------------------------------
>   Michael L. VanLoon                           Project Vincent Systems Staff
>   michaelv@iastate.edu              Iowa State University Computation Center
> ------------------------------------------------------------------------------