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Newsgroups: comp.os.386bsd.development Path: sserve!newshost.anu.edu.au!munnari.oz.au!mel.dit.csiro.au!etrog!kjb From: kjb@cgl.citri.edu.au (Kendall Bennett) Subject: Re: V86 mode & the BIOS (was Need advice: Which OS to port to?) Message-ID: <kjb.745145142@manda.cgl.citri.edu.au> Sender: news@etrog.se.citri.edu.au Organization: Collaborative Information Technology Research Institute References: <107725@hydra.gatech.EDU> <245jrfINNrc0@bonnie.tcd-dresden.de> <hastyCBLnIF.Cyq@netcom.com> <1993Aug11.164429.6015@fcom.cc.utah.edu> Date: 12 Aug 93 08:45:42 GMT Lines: 43 terry@cs.weber.edu (A Wizard of Earth C) writes: >In article <hastyCBLnIF.Cyq@netcom.com> hasty@netcom.com (Amancio Hasty Jr) writes: >>I am very interested on having a dosemu box for 386bsd. I am tired of >>initializing S3 cards and extracting the info from S3 like if I was >>a dentist pulling a teeth out of a patient not under anestesia. >I am concerned about the use of a VM86 to do S3 card initialization. What >happens when I take the same card and put it in a machine where a VM86 is >either not possible or requires writing an entire hardware emulation? >I am thinking in particular of the EISA-based DEC Alpha and MIPS R4000 >boxes currently being ported. With all the gyrations, as annoying as they >may be, I can still use the cards on diverse architectures without being >tied to an 8086 instruction set melted into the BIOS, because the BIOS is >ignored. If you stop ignoring the BIOS, this breaks these platforms. This is a valid point, but you must realise that ignoring the BIOS is not really a viable solution. Both Microsoft and IBM tried to do this with OS/2 and Windows NT, but have both gone back to using the BIOS at initialisation time to identify the underlying video hardware. This is really the only plausible solution since then you can write an X11 server that will work for generic VESA VBE video cards, without any type of acceleration. The biggest problem with video card initialisation, is that unless you know _everything_ about the underlying hardware, it is very hard to set up the correct video mode timings without a lot of hassles (ask anyone involved with the XFree86 and XS3 about this). By using the BIOS, you can let the hardware decide how it should be done. I also don't see that this is that much of a problem. Given the fact that you may be on a different arhictecture, you can simply have two compilable versions - one that uses the dosemu stuff to access the BIOS, and another that goes directly to the hardware for new architectures like the MIPS and DEC Alpha. +------------------------------------------+-------------------------------+ | Kendall Bennett | Internet: | | RMIT Advanced Computer Graphics Centre | kjb@citri.edu.au | | CITRI Building, 723 Swanston Street | rcskb@minyos.xx.rmit.oz.au | | Carlton Victoria 3053 AUSTRALIA. | | +------------------------------------------+-------------------------------+