From: J.P. M. <jp...@it...> - 2003-07-27 17:57:18
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On Sun, 27 Jul 2003 14:36:32 +0100 "William F B Labbett" <zh...@nt...> wrote: > > There is a little contention, however, about which modes are available > > (for instance, 320x200x15, 320x200x16, 320x200x24 etc). If you stick with > > 640x480 or 800x600, there shouldn't be any problem. > > someone told me 1024 by 768 was a standard 8-bit VESA res > is that right? Yes, that should be supported by all VESA cards with 1MB of memory or more. > > The trouble is, that when VESA was defined, everything was done in real > > mode, > > what is real mode plz? A CPU mode. It mimicks the 8086 processor. You get up to 1MB of memory, but in 64k chunks. DOS runs in real mode. As of about 1993, most programs were written in Protected Mode, which was added with the 386 processor. In theory you get something like 32 Terabytes of memory, in 4GB chunks. With Windows, Linux and most other systems, they prefer work in a single chunk and you get a maximum of 4GB to play with (which is what the AMD Opteron will fix) It was like the sun had risen for the first time, unless, like me you couldn't afford a 386 at the time. The sun rose a little later for me :) There were all kinds of weird tricks to allow 32-bit programs to be run in DOS.. you had to use a 'DOS extender' or DPMI system. The most popular was called 'DOS4G' and it shipped with the Watcom compiler. Many games used it, such as Doom, System Shock, Duke3d, Descent, Heretic, Simon The Sorcerer 2, etc. If you've ever seen a file called 'DOS4GW', that's what it is. Other people wrote their own proprietary extenders (Beneath A Steel Sky) or used even more bizarre methods (Ultima 7, Pagan, Wing Commander 3) which make it extremely difficult to run these excellent games today. And everyone of college or university age was trying to write their own OS to replace DOS. Only Linus really succeeded, but whatever. It was a really fun time to be a computer geek :-) Then Win95 came along and spoiled it all.. > > Time passed, and people started working in flat protected mode instead, > > with a limit of around 4194304k instead. > > That's a massive difference! > > > > I don't want to write a > > > game and find out that only > > > a handful of people can use it. > > > > Why should this happen? GFX_AUTODETECT should choose a driver that works. > > If you do have detection problems, add a switch on the command line to let > the > > user select a driver themselves. Or some kind of INI file. > > > > > > > > Plz say as much as you can. > > > > > > > Was that enough? :) > > > That was lots but as usual when people explain things to me it often > arouses lots more questions in me :) I only noticed two questions. If there's anything else, ask away. -- JP Morris - aka DOUG the Eagle (Dragon) -=UDIC=- jp...@it... Fun things to do with the Ultima games http://www.it-he.org Reign of the Just - An Ultima clone http://rotj.it-he.org d+++ e+ N+ T++ Om U1234!56!7'!S'!8!9!KAW u++ uC+++ uF+++ uG---- uLB---- uA--- nC+ nR---- nH+++ nP++ nI nPT nS nT wM- wC- y a(YEAR - 1976) |