keshava@walt.cc.utexas.edu (Sanjay Keshava) (04/12/90)
Does anyone have a summary on which combinations of display adapters
can coexist in a PC? In particular, I would like 2 VGA cards
displaying different screens, eventually one will be upgraded to a
TIGA board. Simultaneous display would be great, but I can live with
a soft-switch to toggle between displays. Suggestions of other
combinations (eg CGA-VGA, Mono-VGA, Herc-EGA, etc) are also welcome.
Thanks in advance for any info.
Sanjay
->|<-
Student in the UT Graduate School of Business
DARPA: keshava@ccwf.cc.utexas.edu | Graduation Date: TBD
CSnet: keshava%ccwf@relay.cs.net | Greetings to fellow Anteaters,
UUCP: ...!ut-emx!ccwf.cc.utexas.edu!keshava | Trojans, and Longhorns.hd7x@vax5.cit.cornell.edu (04/13/90)
In article <28045@ut-emx.UUCP>, keshava@walt.cc.utexas.edu (Sanjay Keshava) writes: > Does anyone have a summary on which combinations of display adapters > can coexist in a PC? In particular, I would like 2 VGA cards > displaying different screens, eventually one will be upgraded to a > TIGA board. Simultaneous display would be great, but I can live with > a soft-switch to toggle between displays. Suggestions of other > combinations (eg CGA-VGA, Mono-VGA, Herc-EGA, etc) are also welcome. Basically, you can only have one monochrome adapter and one color adapter. This is because all IBM color adapters use the same memory location for text display, and there would be address conflicts. But monochrome adapters use different addresses. In short, you can have Herc simultaneously with CGA,EGA,or VGA, but you cannot have CGA-VGA or EGA-VGA, for example. In addition, if you go with Herc+IBM standard, you must make sure to set HGC HALF to avoid address conflicts. But, there is one exception to this rule that will allow your dream of two VGA displays. On an IBM PS/2, you CAN have the internal VGA coexist with an IBM 8514/A adapter and monitor. For this to work, one of the displays has to be using one of the 8514/A's advanced modes (1024x768) while the other displays standard VGA (640x480). -Sanjay Aiyagari (HD7X@vax5.cit.cornell.edu)
weisen@eniac.seas.upenn.edu (Neil Weisenfeld) (04/13/90)
In article <3871.26250e21@vax5.cit.cornell.edu> hd7x@vax5.cit.cornell.edu writes: >In article <28045@ut-emx.UUCP>, keshava@walt.cc.utexas.edu (Sanjay Keshava) >writes: >> Does anyone have a summary on which combinations of display adapters >> can coexist in a PC? In particular, I would like 2 VGA cards >> displaying different screens, eventually one will be upgraded to a >> TIGA board. Simultaneous display would be great, but I can live with >> a soft-switch to toggle between displays. Suggestions of other >> combinations (eg CGA-VGA, Mono-VGA, Herc-EGA, etc) are also welcome. > [ stuff deleted ... ] > >But, there is one exception to this rule that will allow your dream of two VGA >displays. On an IBM PS/2, you CAN have the internal VGA coexist with an IBM >8514/A adapter and monitor. For this to work, one of the displays has to be >using one of the 8514/A's advanced modes (1024x768) while the other displays >standard VGA (640x480). > >-Sanjay Aiyagari (HD7X@vax5.cit.cornell.edu) I wasn't the programmer who worked on the project, but... I believe that the 8514/A will drive two monitors -- one in text and one in graphics (both color) Neil _____ _____ ------------------------------------ \ / \ / / Neil Weisenfeld \ / \ / / Computer Science and Engineering \ / /\ \ / / Unviersity of Pennsylvania \ / / \ \ / / -------------------------------------- \ / / \ \/ / InterNet: weisen@eniac.seas.upenn.edu \ / / \ / USPS: 3700 Spruce St. Box 572 \/____/ \_____/ Philadelphia, PA 19104 --------------------------------------