Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!munnari.oz.au!csource!david
From: david@csource.oz.au (david nugent)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: extended memory
Message-ID: <768@csource.oz.au>
Date: 17 Dec 90 06:01:47 GMT
References: <18374@rasp.eng.cam.ac.uk> <15090024@hpspcoi.HP.COM>
Organization: Unique Computing Pty Ltd., Melbourne, Aust.
Lines: 50

In article <15090024@hpspcoi.HP.COM> dlow@hpspcoi.HP.COM (Danny Low) writes:

>>(Kevin A.Price) 
>>We have a 286 PC/AT with 640k conventional memory and 384k
>>extended memory which is located at address 1 Megabyte.
>
>This does not sound quite right. It looks like you have 1MB of 
>convention memory divided into the usual 640K of available
>and 384K of reserved memory and not 640K of conventional and 384K of
>extended memory.

Eh?  The "usual" in most AT machines with 1 meg is that the upper 384K
starts at the 1 meg mark, NOT occupying so-called "reserved" areas.

I've only seen one AT/286 - a Compaq some time back - which mapped it's
memory otherwise (some technical reasons why, but in any case the RAM was
still not "available" for use by applications or device drivers).


> I do not believe you can add extended memory
> in anything less than 512KB chunks.

Sure you can.  9 x 64K RAM chips in one - many extended
memory boards can take them.


> The 384KB in the 640KB to 1MB address range is reserved but 
> is still part of the conventional memory space. Because much of 
> it is not in actual use, it is possible to "high load" TSRs 
> and drivers into this area.

Oh dear.  Where do I start?  :-)

No, it's not possible to load TSR's and device drivers into this
so-called "conventional" memory, with the exception of using the
extra 64K available via the A20 line at the 1 meg boundary....


> Try QRAM or Move'EM. They are designed to do this with 286 
> machine with or without the C&T NEAT chipset.

UNLESS - you have the C&T NEAT chipset or a true LIMS 4.x memory card,
using QRAM and Move'Em.  But then, we're not discussing "extended"
memory then, but "expanded" memory, which is an entirely different
thing.

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