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: <25A65F5E.1015@maccs.dcss.mcmaster.ca>
Date: 6 Jan 90 21:13:02 GMT
References: <7682@sunvice.UUCP>
Reply-To: cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn)
Organization: McMaster University, Hamilton, Ontario
Lines: 58

In article <7682@sunvice.UUCP> jeff@sunvice.UUCP (Jeff Rabin-Sun-Ft. Lauderdale FL-SE) writes:
$Could someone please post short definitions for LIMM, EEMS, EMS and any
$relationships between them.   Which is hardware dependent, and which is
$software?  

LIM:  Lotus-Intel-Microsoft.  This refers to the fact that the EMS 3.2 and
	higher specs were produced jointly by these three companies.

EMS:  Expanded Memory Specification.  This is the particular spec (e.g. 3.2
	or 4.0) used; also identifies the spec as one of the LIM family.

EEMS:  I forget what the first E stands for.  This is an enhancement to
	EMS 3.2 from (I believe) Ashton-Tate, Quadram, and AST which allows
	things like mapping memory into the conventional memory area.  Most,
	if not all, of this was included into EMS 4.0.

   The design of the hardware is left up to the manufacturer; the hardware
is interfaced to the user's software through the EMM (Expanded Memory Manager)
which is a driver that you include in your config.sys file.  All EMMs for a
given spec (e.g. EMS 4.0) provide the same interface to the software.  Due
to hardware differences, the EMM for a given piece of hardware generally will
work only on that particular board.

   I quote from _Advanced MS-DOS_, first edition (Duncan), p. 441, without
permission:

	The Lotus/Intel/Microsoft Expanded Memory Specification (EMS)
	defines a hardware/software subsystem, compatible with 8088/
	8086/80286-based microcomputers running MS-DOS, that allows
	applications to access as much as 8 megabytes of bank-switched
	random access memory.

   And now from page 182:

	At the Spring COMDEX in 1985, Lotus Development Corporation and
	Intel Corporation jointly announced the Expanded Memory Specification
	3.0 (EMS), which was designed to head off rapid obsolescence of the
	older PCs due to limited memory.  Shortly afterward, Microsoft
	announced that it would support the EMS ... Subsequently, the
	Expanded Memory Specification 3.2, modified from 3.0 ... was
	released as a joint effort of Lotus, Intel and Microsoft.

	The Intel/Lotus/Microsoft Expanded Memory Speficiation is a func-
	tional definition of a bank-switched memory-expansion subsystem.
	It is comprised of hardware expansion modules and a resident driver
	program specific to those modules.

	The EMS provides a uniform means for applications to access as much
	as 8 megabytes of memory.  The supporting software ... provides a
	hardware-independent interface between application software and the
	expanded memory board(s).

   (The first edition is too old to cover EEMS or EMS 4.0)
-- 
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