Path: utzoo!censor!geac!maccs!cs4g6ag
From: cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn)
Newsgroups: comp.sys.ibm.pc
Subject: Re: LIMM, EEMS, EMS, ???
Message-ID: <25A66073.1203@maccs.dcss.mcmaster.ca>
Date: 6 Jan 90 21:17:39 GMT
References: <7682@sunvice.UUCP> <2504@jato.Jpl.Nasa.Gov>
Reply-To: cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn)
Organization: McMaster University, Hamilton, Ontario
Lines: 20

In article <2504@jato.Jpl.Nasa.Gov> kaleb@mars.UUCP (Kaleb Keithley) writes:
$ [...] In general (if not specifically) it involves hardware paging of
$memory on an LIM EMS board into a hole in ROM above A000:0000.  The current
$revision of this standard is 4.0. [...]

   Pretty close.  EMS 3.2 and earlier mapped four 16K pages into one
64K segment in an address hole above segment A000.  EMS 4.0 allows you to
have substantially more than four pages, including the possibility to map
expanded memory into large portions of the conventional memory space (the
first 640K of memory) to allow quick switching of that memory space for
multitasking operating systems (previously, the contents of memory would
have been copied into EMS 64K at a time, and the new contents would have
been copied down from EMS right after this ... time-consuming, to say the
least).

-- 
Stephen M. Dunn                               cs4g6ag@maccs.dcss.mcmaster.ca
          <std_disclaimer.h> = "\nI'm only an undergraduate!!!\n";
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    If it's true that love is only a game//Well, then I can play pretend