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From: ftp@hpcvlo.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: IBM PC memory map locations
Message-ID: <1610017@hpcvlo.HP.COM>
Date: Mon, 6-Jul-87 12:49:02 EDT
Article-I.D.: hpcvlo.1610017
Posted: Mon Jul  6 12:49:02 1987
Date-Received: Thu, 9-Jul-87 05:52:06 EDT
References: <193@vmix.UUCP>
Organization: Hewlett-Packard Co., Corvallis, OR, USA
Lines: 18

According to the info in my manuals and books, the upper memory area is
organized like this:

            a000       video (EGA, VGA)
            b000       video (Mono, CGA, VGA, EGA)
            c000       expansion ROMs
            d000       ROMs (expansion and/or BIOS, I'm not sure)
            e000       ROM (usually BIOS on newer machines)
            f000       ROM (always BIOS)

Seems to me you're pretty much stuck with having to somehow share the 128K
of video space with the other video cards.  (CGA actually starts at b800,
while mono starts at b000, so they can both run at the same time.)
All addresses in this note are hex SEGMENT addresses.

Everett Kaser
Hewlett-Packard Co.
Corvallis, OR