Path: utzoo!attcan!uunet!van-bc!ubc-cs!uw-beaver!cornell!mailrus!tut.cis.ohio-state.edu!pt.cs.cmu.edu!b.gp.cs.cmu.edu!Ralf.Brown@B.GP.CS.CMU.EDU
From: Ralf.Brown@B.GP.CS.CMU.EDU
Newsgroups: comp.sys.ibm.pc
Subject: Re: What's Extented memory good for??
Message-ID: <251a2d86@ralf>
Date: 22 Sep 89 13:03:02 GMT
Sender: ralf@b.gp.cs.cmu.edu
Organization: Carnegie Mellon University School of Computer Science
Lines: 31
In-Reply-To: <2518F275.22253@maccs.dcss.mcmaster.ca>

In article <2518F275.22253@maccs.dcss.mcmaster.ca>, cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) wrote:
 >   AQA was an extension to LIM EMS 3.2 designed by AST, Quadram and Ashton-
 >Tate.  I'm not entirely sure of what differences it had; however, there
 >were extra calls available (perhaps AQA is where the idea of more than 4
 >logical pages came from?).

Yes.  Also the idea of multiple sets of mapping registers (AQA had two).
And the idea of backfilling the low 640K with mappable memory (which is
what lets DESQview really fly).

 >   Fortunately, LIM included AQA in the EMS 4.0 specification, so programs
 >written to require AQA will work under EMS 4.0.

Unfortunately, the calls are different, even though EMS 4.0 provides a
superset of the AQA functionality.  Programs that were written for AQA
must be modified to use the different calls in the LIM4 API (hopefully
while retaining AQA compatibility).

 >   BTW, are there any programs out there (common ones, I mean) that require
 >either AQA or EMS 4.0?

Yep.  DESQview through version 2.00 requires AQA, versions 2.01 and up
support both AQA and EMS4.
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