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From: mms00786@uxa.cso.uiuc.edu
Newsgroups: comp.sys.ibm.pc
Subject: Re: QEMM 5.0 Slo-o-o-o-ws system DMA
Message-ID: <46500128@uxa.cso.uiuc.edu>
Date: 28 Jun 90 18:54:00 GMT
References: <3863@trantor.harris-atd.com>
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Nf-ID: #R:trantor.harris-atd.com:3863:uxa.cso.uiuc.edu:46500128:000:491
Nf-From: uxa.cso.uiuc.edu!mms00786    Jun 28 13:54:00 1990


Umm, since the address translation unit is built into the 80386 as far as
I know, what, then, is the advantage of DMA? Obviously, since the 80386's
translation unit is tied up, the 'rest' of the 80386 cannot be doing anything
even if all it needs is in the cache /* assuming various things about the
cache */. Now, obviously, memory protection schemes and DMA have been around
for a long time, so anyone care to mention how a VAX or IBM or whatever
handles this type of situation?

Milan
.