Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!apple!portal!cup.portal.com!ekalenda
From: ekalenda@cup.portal.com (Edward John Kalenda)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Need help on unix->dos port
Message-ID: <41927@cup.portal.com>
Date: 2 May 91 06:02:18 GMT
References: <1991May1.091701@ecn.purdue.edu>
Organization: The Portal System (TM)
Lines: 26

>I've developed a C program on unix (Sun SPARC 1) that I need to port to
>DOS. The problem is that this program allocates large structures, and 
>the total memory requirements exceed 1Mb at times. Is there any way that
>I can get over the 640Kb limit of DOS without altering my code too much?
>I don't have much experience with the PC, so I'd like to avoid a lot of
>hacking if possible. I read an ad. in the BYTE magazine for something 
>called the "DOS extender" which claims to get over the 640Kb limit. Has
>anyone used this software? In terms of ease of use, applicability etc.,
>is it worth the $1000 or so they are asking for it? 

The other approach commonly used is to use Expanded Memory. Your program
will be able to run on any PC that has an EMS board installed (or a 386
with a Memory Manager running). The main hassle is that you will need to
rework your memory usage to use the memory handle concept. This may be
far more than you will want to do.

I don't remember the name of the product, but there iss one that lets you
allocate memory and refer to it by handles which you "lock" and "unlock"
as you need them. It will use main memory, expanded memory, and page
unlocked blocks to and from disk as needed. Your individual memory blocks
are small (16K or so) but you can work with several megabytes worth in a
fairly transperant fashion. Not aas good as Unix virtual memory but it
works.

Ed
ekalenda@cup.portal.com