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From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Why is DOS limited to 640K?
Summary: It isn't
Message-ID: <1142@crdos1.crd.ge.COM>
Date: 16 Oct 89 16:38:31 GMT
References: <8909270503.AA28536@euler.Berkeley.EDU> <10253@cbnews.ATT.COM>
Reply-To: davidsen@crdos1.UUCP (bill davidsen)
Organization: GE Corp R&D Center
Lines: 17

In article <10253@cbnews.ATT.COM>, rock@cbnews.ATT.COM (Y. Rock Lee) writes:
|  Why is a plain DOS limited to 640K memory?

  It isn't. It's just that (a) IBM configures their DOS that way, and
(b) some video boards start after 640k. MS-DOS uses all of the memory in
other machines such as the Tandy 2000 (768k), but programs which write
directly to memory won't run. It's a problem with the applications.

  There is a patch for PC-DOS to use more memory, but you restrict the
programs you can run. Some programs can also take advantage of memory
about 640k but not contiguous, and the 63k about 1MB which can be
addresses by the 286.
-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
"The world is filled with fools. They blindly follow their so-called
'reason' in the face of the church and common sense. Any fool can see
that the world is flat!" - anon