Path: utzoo!yunexus!maccs!cs4g6ag
From: cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Why is DOS limited to 640K?
Message-ID: <254F201F.22212@maccs.dcss.mcmaster.ca>
Date: 1 Nov 89 16:55:58 GMT
Article-I.D.: maccs.254F201F.22212
References: <8909270503.AA28536@euler.Berkeley.EDU> <10253@cbnews.ATT.COM> <126@euteal.ele.tue.nl> <16320@dartvax.Dartmouth.EDU>
Reply-To: cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn)
Organization: McMaster University, Hamilton, Ontario
Lines: 28

$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.

   That's no big problem ... if you do have nore than the 640K your machine
looks for, there are programs that will change the PC's internal count
of ho much memory it has.  These programs do the following:

1.  Find out how much RAM _really_ is there
2.  Change the low-memory variable that says how much memory you have
3.  Reboot the machine

   Bingo, you have more than 640K.  Anyone who wants a copy of such a
program (I've never tried it, but I imagine it works; it was printed in
BYTE a few years back), just e-mail me a note saying "I want that memory
expander" or something similar and I'll mail you the program (if you
want source, too, let me know).

-Steve

-- 
Stephen M. Dunn                               cs4g6ag@maccs.dcss.mcmaster.ca
          <std_disclaimer.h> = "\nI'm only an undergraduate!!!\n";
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