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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!solace!news.stealth.net!www.nntp.primenet.com!nntp.primenet.com!news.mathworks.com!hunter.premier.net!news1.erols.com!news From: Ken Bigelow <kbigelow@www.play-hookey.com> Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Simutaneous mono and vga under FreeBSD... Date: Tue, 24 Sep 1996 19:23:12 +0000 Organization: Erol's Internet Services Lines: 34 Message-ID: <32483520.628A@www.play-hookey.com> References: <32388517.BA4@wsg.net> <3238632A.6516@www.play-hookey.com> <51eoiu$6ck@diemos.isdfa.sei-it.com> <323C1975.4FA7@www.play-hookey.com> <01bbaa1e$83d5fa80$070906c6@roanoke> Reply-To: kbigelow@www.play-hookey.com NNTP-Posting-Host: kenjb05.play-hookey.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 3.0 (Win16; U) Arlie Davis wrote: > > Ken Bigelow <kbigelow@www.play-hookey.com> wrote in article > <323C1975.4FA7@www.play-hookey.com>... > > > Now, if you want the Hercules card to run in text mode (which was the > > original stated requirement) it will occupy at least 32K at segment B000 > > (in half mode; 64K in full mode). You can't change this, and any VGA > > graphics mode can't be allowed to use this memory space. This > > tremendously limits the graphics modes and amount of memory they can > > access directly. > > I agree with everything you've written about simultaneously using multiple > video adapters, except this. Many video cards can map their frame buffers > into a linear region of the processor's physical address space, far beyond > the realistic end of physical memory. For example, the Diamond Viper VLB > does this (I think); it can map it's frame buffer to any of these physical > addresses: 40000000H, 80000000H, or A0000000H. (I may be wrong on the > details, but the concept is right.) > The concept is indeed correct. I can only conclude that the combinations I was using at the time, for whatever reason, would not support this mode of operation. Whether it was the video card, the ROM BIOS, the support chipset, or whatever, I can't say now. All I can report is that all such attempts resulted in disaster on two displays as soon as I went into a VGA graphics mode. So, I gave it up as hopeless (which it was at the time). -- Ken Are you interested in | byte-sized education | http://www.play-hookey.com over the Internet? |