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From: boesch@Shasta.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Accessing extended memory in AT - a question.
Message-ID: <1679@Shasta.STANFORD.EDU>
Date: Wed, 20-May-87 20:07:56 EDT
Article-I.D.: Shasta.1679
Posted: Wed May 20 20:07:56 1987
Date-Received: Fri, 22-May-87 00:57:46 EDT
Reply-To: boesch@Shasta.UUCP (Brian Boesch)
Organization: Stanford University
Lines: 19
Keywords: extended memory

---
On an PC-AT, the memory is broken into the first 640K
and extended memory (which resides at addresses higher than 1M).
Since DOS runs in real mode (20 bit addresses), how do you access
the extended memory?

I know that in protected mode all addresses are accessable but the 
286 manual says that once in protected mode you cannot return to real mode.

Any help would be appreciated, code examples in any reasonable language
would be great.

Please don't clutter the net, send me email and I will post a summary.

thanks
  Brian Boesch

  boesch@shasta.stanford.edu
  boesch@shasta.UUCP