From:	Glen Miner <gminer AT ca DOT newbridge DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Memory Protection
Date:	Fri, 15 Nov 1996 07:47:00 -0500 (EST)
Organization:	Newbridge Networks Corporation
Lines:	33
Message-ID:	<Pine.SUN.3.90.961115072919.19765A-100000@coop10>
NNTP-Posting-Host:	138.120.136.238
Mime-Version:	1.0
To:	Ian D Romanick <idr AT cs DOT pdx DOT edu>
In-Reply-To:	<199611142317.PAA15327@sirius.cs.pdx.edu>
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

> > introduced to the wonderfull world or memory protection. It seems that
> > video memory is protected, and I'm not allowed to freely read/write in it.
> 
> Not exactly true.  All memory below *physical* 1Mb is *not* protected. 
> However, you can't just use a normal pointer to access it.

Aahhh, I see. I posted slightly in haste; I read much documentation last 
night, and learned about the dos memory functions.

> > If I disable memory protection, will my program run faster?
> 
> No.

Really? I find this hard to believe. How does it detect memory 
violations? I would tend to think that it doesn't managed to determine 
this for "free", and would have to waste cycles in order to detect it.

> > Would it be wiser to somehow take ownership of the video memory buffer so
> > that it doesn't have to be protected from me?
> 
> The FAQ details about half a dozen different ways to access video
> memory.  Please take a look at http://www.delorie.com/djgpp.  Hope this
> helps.

Ahh, I see. I found a lovely webpage devoted entirely to what I'm looking 
for. Thanks for your help! 

Peace
===[ Gabo / [ABC] : gaminer AT undergrad DOT math DOT uwaterloo DOT ca ]===================
Latest ABC Shogi: http://www.undergrad.math.uwaterloo.ca/~gaminer/shogi.html
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