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From: stevel@eleazar.dartmouth.edu (Steve Ligett)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Why is DOS limited to 640K?
Message-ID: <16320@dartvax.Dartmouth.EDU>
Date: 24 Oct 89 13:46:30 GMT
References: <8909270503.AA28536@euler.Berkeley.EDU> <10253@cbnews.ATT.COM> <126@euteal.ele.tue.nl>
Sender: news@dartvax.Dartmouth.EDU
Reply-To: stevel@eleazar.dartmouth.edu (Steve Ligett)
Organization: Dartmouth College, Hanover, NH
Lines: 17

In article <126@euteal.ele.tue.nl> blitter@ele.tue.nl (Paul Derks) writes:
>In article <10253@cbnews.ATT.COM> rock@cbnews.ATT.COM (Y. Rock Lee,55212,cb,1J312E,6148604774) writes:
>>Why is a plain DOS limited to 640K memory?
...
>DOS on an IBM PC (or compatible) IS limited to 640k simply because the
>memory map of the PC only has room for 640k RAM and the rest is reserved 
>for ROM's and video ram.

PC-DOS is not limited to 640K.  At least version 2.1 wasn't, I'm not
sure about the newer ones.  That's because I sold my IBM PC.  On the
old PC, you set switches to tell it how much ram it had.  It wasn't
"smart" enough to look.  I had 704K (and MDA) in mine, and it believed
me when I told it so.  Alas, my "new" XT figures out how memory it has
by itself, and so only looks for 640K.
--
Steve Ligett       steve.ligett@dartmouth.edu or
(decvax harvard linus true)!dartvax!steve.ligett