Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!ucbvax!mtxinu!ed
From: ed@mtxinu.COM (Ed Gould)
Newsgroups: comp.unix.sysv386
Subject: Re: ESIX and Caching Motherboards
Message-ID: <1991Mar29.184802.17438@mtxinu.COM>
Date: 29 Mar 91 18:48:02 GMT
References: <824@oss670.UUCP> <1991Mar29.063058.18124@jwt.UUCP>
Reply-To: ed@mtxinu.COM (Ed Gould)
Organization: mt Xinu, Berkeley
Lines: 25

>>	"Our Acer's 32kb onboard cache must be disabled for
>>	proper installation.  The same is probably true for
>>	other machines with caches."

>ESIX runs without a hitch on my cached system.  This "reviewer" is
>rather bold to make such a statement based on a sample size of one.

This may not be based on a sample at all, but on analysis.  The
reason I can imagine for requiring the cache to be disabled is
this:  It's a write-back cache that doesn't snoop on DMA, and
there's no software support to maintain cache consistency.

One of the things that this means is that if there are no DMA
devices, then running with the cache enabled will work.  If there
are DMA devices, then it won't.

I am currently considering an Arche 486 box, containing a DMA-snooping
write-back cache, for personal use.  Does anyone have any experience
with Arche or their hardware?

-- 
Ed Gould                    mt Xinu, 2560 Ninth St., Berkeley, CA  94710  USA
ed@mtxinu.COM		    +1 415 644 0146

"I'll fight them as a woman, not a lady.  I'll fight them as an engineer."