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Mail Archives: opendos/2003/11/30/21:54:05

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Message-ID: <01FD6EC775C6D4119CDF0090273F74A4FD6C76@emwatent02.meters.com.au>
From: "da Silva, Joe" <Joe DOT daSilva AT emailmetering DOT com>
To: "'opendos AT delorie DOT com'" <opendos AT delorie DOT com>
Subject: RE: several technical problems [big DOS apps]
Date: Mon, 1 Dec 2003 13:58:57 +1100
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Reply-To: opendos AT delorie DOT com

Sure, you _could_ mess around with EMS or XMS to access
more memory within a DOS application, but few people bother
with this approach today. Incidentally, Arachne is one of those
applications that uses memory in this way.

These days, most large DOS applications use 32 bit protected
mode, giving them access to all the memory without any
messing around on the part of the programmer. For example,
GNU Pascal, Delphi with WDOSX, FreePascal and TMT Pascal
all produce 32 bit protected mode applications for DOS. Easy.
Need to use an array of 2 million bytes? No problem, go right
ahead! I'm sure there would be a similar situation with other
languages, such as C (eg. with GCC/DJGPP).

Donald :  I think the above answers your question ...
So what do I need to do to make use of "beyond 640k"?

Joe.

> -----Original Message-----
> From:	shadow AT shadowgard DOT com [SMTP:shadow AT shadowgard DOT com]
> Sent:	Friday, November 28, 2003 6:18 PM
> To:	opendos AT delorie DOT com
> Subject:	RE: several technical problems
> 
> On 28 Nov 2003 at 14:38, da Silva, Joe wrote:
> 
> > Leonard's statement that "anything running in any DOS" can only
> > use 640k, is not true of course, it is only true for some applications.
> > But as a FreePas user, you would already know this.
> 
> Sure, there's EMS, and XMS, and various other 
> tricks, including the HMA. But a program complaining 
> about being "out of memory" is almost always out of 
> conventional RAM. 
> 
> Yes, programs like QEMM can allow multiple programs 
> to have their own conventional RAM. But that max 
> limit still exists.
> 
> I've done stuff like use QRAM and included utilities 
> to get 768k of "conventional" RAM on an XT and on a 
> 286. And used QEMM with multiple tasks/sessions on 
> 386 and 486 systems. 
> 
> So I do have more than a passing familiarity with 
> what happens with DOS based software.
> 
> --
> Leonard Erickson (aka shadow)
> shadow at krypton dot rain dot com
> 

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