Article View: comp.os.msdos.misc
Article #3497Re: Does MSDOS 5.0 support Upper Memory on a 286?
From: Wm E Davidsen Jr
Date: Tue, 25 Jun 1991 13:20
Date: Tue, 25 Jun 1991 13:20
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I think you are confusing high memory with upper memory. High memory starts at FFFF:0000 and goes up, on both [23]86. UMA is between C000 and F000 (or maybe B000 is the manager is smart enough to sneak under the VGA). So on a 286 you get 64k for the DOS, but not the memory space for the UMA. Since the 286 doesn't have the right hardware to do UMA, it would have to be faked in software. The software would take about as much space as it saved. No gain, so they didn't do it. I think you could do it in less, but that's the condition which prevails. You still save 64k, which would seem useful. -- bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) GE Corp R&D Center, Information Systems Operation, tech support group Moderator comp.binaries.ibm.pc and 386-users digest.
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!crdgw1!crdos1!davidsen From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) Newsgroups: comp.os.msdos.misc Subject: Re: Does MSDOS 5.0 support Upper Memory on a 286? Message-ID: <3464@crdos1.crd.ge.COM> Date: 25 Jun 91 13:20:07 GMT References: <811@wa3wbu.UUCP> <1991Jun21.082150.11675@csc.canberra.edu.au> <46R4MKP@dri.com> Reply-To: davidsen@crdos1.crd.ge.com (bill davidsen) Organization: GE Corp R&D Center, Schenectady NY Lines: 16