Path: utzoo!attcan!uunet!mcvax!enea!tut!mk59200
From: mk59200@tut.fi (Kolkka Markku Olavi)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Use of expanded memory on System 2 Model 50
Keywords: How to?
Message-ID: <4209@varis.tut.fi>
Date: 18 Jul 88 10:45:58 GMT
References: <322@mruxd.UUCP>
Organization: Tampere University of Technology, Finland
Lines: 31

In article <322@mruxd.UUCP> afd@mruxd.UUCP (A Dietz) writes:
>The model 50 has 1M on board, but DOS has access only to 
>640K.  How do I get to the other 360K, designated as "expanded
>memory"?  I have compiled a program that will not fit into
>the useable memory (640K), yet is far less than the 1M available.
>
>A Dietz
>Bellcore, Morristown
>(ulysses, rutgers, bellcore)!mruxd!afd

Here are two answers to your problem:

1. The hi-tech approach
	Buy 2 or 4 MB of additional memory, a large and fast
	hard disk and OS/2 or Unix.  Now you have virtual
	memory, and you can make programs as large as you like
	(well, almost).

2. The lo-tech solution (ie. use your brains instead of wallet)
	Modify the program to run in 640K memory: use overlays,
	temporary files, optimize your algorithms etc.

The extended memory can be used under Mess-DOS as RAM-disk
or disk cache.  To access it, you must switch the 80286 to
protected mode, copy the stuff you need to the 640K "normal"
area and switch back to real mode.  This isn't trivial at all.

--
	Markku Kolkka		| Tampere University of Technology
	mk59200@tut.fi		| Tampere, Finland
	...!mcvax!tut!mk59200	|