Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!bionet!apple!dlyons
From: dlyons@Apple.COM (David Lyons)
Newsgroups: comp.sys.apple
Subject: ROM-3 GS Memory Expansion slot
Message-ID: <34535@apple.Apple.COM>
Date: 5 Sep 89 19:41:25 GMT
References: <8909021018.AA01275@trout.nosc.mil>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 25

In article <8909021018.AA01275@trout.nosc.mil> sb@pro-generic.cts.com (Stephen Brown) writes:
>Can anyone comment on the memory expansion slot in the new version of the
>Apple IIGS (IIbdGS).  I am wondering how compatible this slot is with the
>original IIGS, and what will happen if you were to stick a memory expansion
>card (such as Apple's own, or an AE card) into the slot. Would the machine get
>confused and sit there twiddling its thumbs? Would the extra memory be mapped
>above and beyond the motherboard RAM?   Just wondering.

Apple's card works fine--yes, the extra RAM is mapped above the motherboard
RAM.

Third-party cards work fine *if* they use the signals intended for deciding
which row of RAM chips to activate at a given time.  As I understand it,
some 3rd-party cards ignore these signals and decode the address bus directly,
allowing them to get more rows of chips on the card than they could otherwise.
Such cards need to be revised to work properly in the ROM-3 GS.

 --Dave Lyons, Apple Computer, Inc.          |   DAL Systems
   AppleLink--Apple Edition: DAVE.LYONS      |   P.O. Box 875
   AppleLink--Personal Edition: Dave Lyons   |   Cupertino, CA 95015-0875
   GEnie: D.LYONS2 or DAVE.LYONS         CompuServe: 72177,3233
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   My opinions are my own, not Apple's.