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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.mel.connect.com.au!news.mira.net.au!news.vbc.net!samba.rahul.net!rahul.net!a2i!hustle.rahul.net!rahul.net!a2i!news.clark.net!noos.hooked.net!www.nntp.primenet.com!nntp.primenet.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: Sun, 15 Sep 1996 14:57:57 +0000 Organization: Erol's Internet Services Lines: 40 Message-ID: <323C1975.4FA7@www.play-hookey.com> References: <32388517.BA4@wsg.net> <3238632A.6516@www.play-hookey.com> <51eoiu$6ck@diemos.isdfa.sei-it.com> 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) To: vanvleet@rrnet.com James Van Vleet wrote: > > This is not really true.. I have two machines both running Win95 > just fine with a Monochrome and a SVGA card. It is great for > debugging programs. Both are running 1024x768 without problems. > Just type "mode mono" in a dos box. I too would be interested in a > technique for FreeBSD. > > -James > You weren't running an old Hercules card at any 1024x768 -- they didn't go that high. The basic problem is unchanged: to use two video cards for different displays at the same time, they cannot overlap in either memory usage or port addresses, nor in IRQ if they use it (EGA used IRQ2 for a vertical retrace signal). 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 see only one way to avoid the conflict. At least one video card, which must be the VGA card since the Hercules card can't, must get *all* of its video specifications via I/O operations to one or more ports, and not by bank-switching memory into the main processor's memory map. If you can find such cards that are mutually exclusive in their addressing and you want to adapt simultaneous drivers for them, you can make the combination work. However, I strongly suspect it will require two VGA cards in mutually exclusive modes, not a VGA card and a Hercules card. -- Ken Are you interested in | byte-sized education | http://www.play-hookey.com over the Internet? |