possible to add an isa graphics card? \ VOGONS

possible to add an isa graphics card?

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First post, by emosun

Posted on 2020-07-30, 18:25

emosun Offline

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Rank: Oldbie
Posts: 554
Joined: 2015-02-24, 17:28

Starting off this is the board

http://www.uktsupport.co.uk/pb/mb/450.htm

The board is inside an AIO machine. The machine currently uses 32mb of ram and a 75mhz overdrive cpu and runs 98 seemingly just fine. (i lightened 98 a lot)

The challenge that I presented myself (for fun , not for any preactical reason) was to see if I can ADD an external monitor to this AIO machine , and I feel as though I'm VERY close.

The built in graphics on the board works fine. When jumper j19 is set to disable the built in graphics , and jumper j9 is set to enable video irq the machine will work and boot with an ISA cirrus logic CL-5426 in the isa slot.

However the machine will not output video from the onboard with jumper 19 set to disable the onboard (obviously). But when the card is installed with the onboard graphics enabled only the board itself will output , and the graphics card will not be detected by plug n play or by search non plug and play.

This brings me to my current situation and question. I have the isa card activate now , I was wondering if changing the values of what resources it uses in windows in the device properties would effect if the gpu gets detected or not along with the onboard once the jumpers are set back?

And or.... if theres some hardware setting on the board I'm not doing correctly to POSSIBLY get both cards detected once in windows.

(Bonus question) Has anyone ever on earth got 2 isa gpus to work together within windows 98? From my understanding... you would need windows 98 for universal multimonitor support , and you would also need two windows 98 compatible isa graphics cards. but i'm told possibly that all isa graphics cards use the same irq or resources so you can't have more than one? i'm not sure enlighten me

Reply 1 of 1, by jakethompson1

Posted on 2020-07-30, 20:13

jakethompson1 Offline

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Posts: 1353
Joined: 2015-11-17, 04:16

When you change the resources assigned in Windows 95, and the card is a non-Plug and Play ISA card, all you're doing is informing Windows 95 of what the settings are. It's only PnP cards where you actually have the ability to change the resources from the GUI.

With non-PnP cards, you either have to change jumpers on the card, or use a special configuration utility just for that card.

Anonymous Coward pointed out on the other thread that there are actually some ISA VGA cards that have the ability to be set as a "secondary" card. I have never looked into that before but here is an example of the settings you would need. https://arvutimuuseum.ee/th99/v/E-H/51384.htm I can't imagine your CL-GD5426 card would have those. I also have no idea what i/o ranges and memory ranges it would use, or whether that's even standardized for a second card.

Multiple VGA cards were not contemplated in the age of ISA. Most cards are hardcoded to the correct i/o ports and upper memory address ranges for a VGA card. It's only special cards like that ELSA where that can be changed.

Plus, as someone else pointed out, apparently Win95 can do multiple monitors but only with special drivers from ELSA, who also made the card I just linked.

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