Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!oliveb!ames!elroy!peregrine!ccicpg!conexch!rob
From: rob@conexch.UUCP (Robert Collins)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Extended memory determination
Keywords: Extended memory
Message-ID: <30421@conexch.UUCP>
Date: 3 Jun 89 04:12:49 GMT
References: <630@hatter.Tops.Sun.COM>
Reply-To: rob@conexch.UUCP (Robert Collins)
Organization: The Consultants' Exchange, Orange County, CA.  (714) 842-6348
Lines: 26

In article <630@hatter.Tops.Sun.COM> rdas@hatter.Tops.Sun.COM (Robin Das) writes:
>Does anyone know how to determine how much extended memory is available on a 286 or 386 
>processor?

There are a couple of ways to do it:
1) There is a CMOS word available for how much RAM is currently in the RAM
   Pool.  The current RAM pool is defined as how much RAM is available after
   VDISK, DISK_CACHE and other utilities that use, or reside in extended
   memory.
2) There is another CMOS word available for how much RAM is in the system.
   This is regardless of VDISK et al.
3) Do it the way the SYSTEM BIOS does it during POST.  This is very
   dangerous since in order to determine how much ram is there, you must
   look for ram being written to 2 locations (a non-existant address
   line).  And guess where you will overwrite using this method?  Right
   over your interrupt vectors.

I'm sure some other users can give you the CMOS locations, as I'm too
lazy right now to look them up.


-- 
"Worship the Lord your God, and serve him only."  Mat. 4:10
Robert Collins                 UUCP:  ucbvax!ucivax!icnvax!conexch!rob
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