Message-ID: <k3$OilAm+j9yEwux@darkblak.demon.co.uk>
Date: Mon, 3 Feb 1997 19:42:30 +0000
To: opendos AT mail DOT tacoma DOT net
From: "Ian 'DrDebug' Day" <Ian AT darkblak DOT demon DOT co DOT uk>
Subject: Re: [opendos] speeding up command.com
In-Reply-To: <1357142637-14672907@diablo.eimages.co.uk>
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Sender: owner-opendos AT mail DOT tacoma DOT net
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In article <1357142637-14672907 AT diablo DOT eimages DOT co DOT uk>, David Cantrell
<david AT diablo DOT eimages DOT co DOT uk> writes
>bartosz AT bielbit DOT bielsko DOT pl wrote:
>> > Question:
>> >
>> > OpenDOS is for x86 processors, right?
>> > You're not going to break things by inserting a little ASM code - >
>>
>>   Maybe we can use some 386, 486, 586 or MMX specyfic opcodes inside
>> Open DOS. Executables will be smaller and faster but all machines
>> with less than (386...MMX) could be dropped into trash.
>
>There would be no benefit in using 386 (or higher) instructions.  All 
>existing DOS apps expect to use a 16-bit operating system, so even if 
>the app is 32-bit internally (such as those compiled with DJGPP), it 
>still has to go 16-bit for talking to device drivers - such as sound 
>cards, CDs, hard disks, and for allocating memory.  If you rewrote 
>these as 32-bit code, you would still have to provide 16-bit 
>emulations of them, just like Win95 does.  And you would get the same 
>code-bloat and horrendous number of bugs as Win95.

Well, it's very easy to use 386 instructions and still keep a 16-bit
arcitecture.

>Anyway, the performance advantage would not be noticeable.  You spend 
>very little productive time at the command prompt, so to gain a 
>performance increase from going 32-bit, you would either have to 
>rewrite all your APPS to be 32-bit, or be the demon-batch-coder-
>from-hell and do all your work in COMMAND.COM.

True.  The only real advantage would be the decrease in size, and thus
the saving of some of that 640K.

On that subject, are there plans to overcome this to some extent?

DrDebug

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