Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uunet!ficc!peter
From: peter@ficc.uu.net (Peter da Silva)
Newsgroups: comp.arch
Subject: Re: I/O, I/O, and off to work I go...
Summary: Amiga raving. Hit N if you don't want to hear it.
Message-ID: <7115@ficc.uu.net>
Date: 27 Nov 89 15:37:58 GMT
References: <1128@m3.mfci.UUCP> <1989Nov22.175128.24910@ico.isc.com> <3899@scolex.sco.COM> <10335@attctc.Dallas.TX.US>
Reply-To: peter@ficc.uu.net (Peter da Silva)
Distribution: usa
Organization: Xenix Support, FICC
Lines: 13

Two busses so DMA doesn't conflict with the CPU? The Amiga's had it since
1985. The major I/O processors (the Copper and Blitter) are limited to
below the 512K line, and extra memory (FAST RAM) goes on a seperate bus.
Other DMA devices may conflict with FAST RAM up to the 16 MB limit of the
68000, but the 68020 and 68030 can access memory beyond that (up to 64 MB
of it on the current 68030 with an (as yet non-existant) daughterboard).

Pretty good for a $1000 box.
-- 
`-_-' Peter da Silva <peter@ficc.uu.net> <peter@sugar.lonestar.org>.
 'U`  --------------  +1 713 274 5180.
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