Date: Sun, 23 Feb 1997 14:08:29 +0200 (EET) From: Indrek Mandre To: "J. Kroll" cc: djgpp AT delorie DOT com Subject: Re: Why DOS so slow? In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII On Sat, 22 Feb 1997, J. Kroll wrote: > I made a program under Linux last night which had I think 10 guys (80x120) > flying around the screen in a sincos pattern over a background of the > palettes (like each horizontal line is color c where c is 0 through > 255 then to 480)... > So it's 640x480x256. > Then I scroll the background downwards. > Short simple program. > I test compile it to DOS and even without the background scrolling it's > terribly blurry... > I had to remove all but one of the guys in order to get it to work. > It works perfectly under Linux without background scrolling and a little > jumpy (you don't notice unless you look) with the background scrolling... > I have P166/64 with 2MB S3 Trio... > > So the question is, what is the problem here? > Is the problem something I'm doing? > Is it the svgalib 1.2.7 (this is djgpp's svgalib I think)? > Is it inadequate support for my specific card? > Or is it just DOS? It is just DOS. I can say that DOS is compared to Linux in svgalib about 10% faster and a lot more stable (I mean access disk during drawing graphics in Linux and watch what happens...). I'v compared the graphics libraries (allegro <-> svgalib) and svgalib was almost always a lot faster. Of course they are not at some ways comparable. Allegro has many other better things like all the bitmap stuff, sound, fl[ic], compressed files and now even 3d and so on. You are possibly doing something Linux specifing in DOS which does not work properly (eg signals, gettimeofday, etc.) The problem is in DOS, in Linux and in your code. Of course I may be wrong and it is a bug in dos port of svgalib but I havn't seen your code so I can't say it surely. Also it may be again that versions diference. /* * Indrek Mandre * indrek AT warp DOT edu DOT ee */