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From: kent@sun.ufnet.ufl.edu (Kent Phelps)
Newsgroups: comp.sys.ibm.pc
Subject: Re: extended vs. expanded
Message-ID: <19330@uflorida.cis.ufl.EDU>
Date: 22 Nov 88 22:16:04 GMT
References: <1717I78BC@CUNYVM> <1090@esunix.UUCP> <1970@hoqax.UUCP>
Sender: news@uflorida.cis.ufl.EDU
Reply-To: kent@sun.ufnet.ufl.edu (Kent Phelps)
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NO, NO, NO.
System memory is from 0 to 640K
The RAM from 640K to 1M is reserved for video RAM and EMS ( expanded ).
Extended RAM is above 1M, not expanded.
EMS stands for Expanded Memory Specification.  There are two versions: 3.2
and 4.0.  Version 4.0 is also referred to as "LIM 4.0".  EMS is a bank
switching scheme that allows PC's that can't physically address RAM above
1M (8088 based machines) to break the 640K barrier.  The differences
between the 3.2 spec and the 4.0 spec is that 3.2 can only expand to
8M and can only be used to store data.  The 4.0 spec can expand up to
32M and can also be used to store applications so you can sort of 
do multi-tasking.  PC Tech Journal's July 1988 issue has a good article
that goes into much greater detail.  Hope this clears up any questions.
.

--
     Kent Phelps        | Internet:  kent@sun.ufnet.ufl.edu
 University of Florida  | UUCP:  ... ????
 Digital Design Facility| Phone: 904-335-8322