View Full Version : Using a secondary display adapter

Anonymous Coward
January 6th, 2005, 11:49 AM
Is there anybody in this forum that has experience using dual video adapter systems? I am trying to assemble a 486 system using this setup, but I seem to be having some difficulties. The reason I would like to use two cards is because I would like to use one as a windows video accellerator, and the other as a DOS VGA graphics only card. There are very few single cards that are fast at doing both. I've tried just about everything except for maybe a P9000 and an S3-964. Anyway the system I am building is mostly EISA. This is because I wish to run my BUS at 50MHz. This means that I don't really like using local bus cards. However, I have decided to use a VLB adapter for DOS modes, because of ISA memory addressing restrictions. I am currently using a Hercules Dynamite Power VLB as my DOS card, which has a reputation for being able to handle the 50MHz bus. So far I have not encountered any stability issues. However, in the Hercules manual I discovered that this card has some issues co-existing with other graphics adapters since it is a memory address hog. Does anyone know of another ET4000W32p card that does not suffer from these problems? So for now I have ruled out the possibility of using another accellerator as a secondary adapter. But, I then learned it is possibe to disable the VGA BIOS on some of the higher end cards and feed the signal in through the VGA feature connector. I purchased an ELSA Winner 2000 4MB EISA adapter so I could try just that!!! The only problem is that I can't seem to get the damn feature connector on the ELSA card working. I read on the newsgroups that some cards do only output or input, but often not both. I am pretty sure my hercules card is output only, but I am not sure about the ELSA. I would hope that it does input, since that is what I need. So basically I need to find out how to get the damn feature connectors working.

Also, while I was fooling around with my system I enabled the VGA BIOS on my ELSA just for the hell of it (using a secondary address), and I discovered that my system would boot under this configuration. I also discovered that I could load windows on the secondary display adapter with the ELSA driver. However, when I try to run the ELSA controller panel, the display cuts out. However, the system does not crash. I am able to ALT-F4 back to the DOS prompt which appears on my primary display. I also discovered that after running some DOS programs, sometimes my machine locks up when I attempt to run Windows on the ELSA. This leads me to believe that there is a memory address conflict between my two cards. This is probably fault of the damn hercules!!! I need to know if there is a way to determine which addresses are being used by my display adapters...and then I need to figure out if it is possible to modify the ranges they are using. If it helps, my ELSA card uses an S3-928 chipset.

If anyone has any recommendations for me for a VLB card that is as fast as my Hercules Dynamite Power that can function at 50MHz, and co-exist with another graphics adapter I would really like to know. I would prefer a card with a feature connector that works in both directions.


January 6th, 2005, 02:54 PM
My recollection is that dual-head support on machines that old is almost non-existent. It's mostly a function of operating system and drivers .. what version of Windows are you using? Do the drivers for the cards have dual-head support?

Back in the old (older) days, dual head support meant a color card of some sort (VGA, EGA, CGA) and monochrome. The code jockeys would do their development work using the mono card, and run their software on the color card. That would let them debug without messing the screens up. (I did this for a while.)


Anonymous Coward
January 6th, 2005, 05:34 PM
I am running windows for workgroups 3.11. Incase I didn't do a good enough job saying so in the description, my intention is not to run Windows spanning two displays. I just wish to run Windows off a secondary display adapter.

January 6th, 2005, 07:25 PM
Oh no, you were clear, don't worry about that. I don't think that WFW could handle two displays anyway ... unless the device driver hid it and made it look like one display.

Good luck with it though .. I'd have sleazed out and just setup another box.


Anonymous Coward
January 6th, 2005, 08:29 PM
Well. I think I have managed to work out a decent solution for now. I believe that Windows locking up has something to do with the univbe TSR being present in memory. I think as long as I have it unloaded before I start Windows I should be fine. I also have a temporary solution for the ELSA driver program. I can run it as long as first switch the driver back to standard VGA (which then runs off the hercules card). Then I can make my changes, exit windows, reload the ELSA driver and restart windows. I guess it sounds like a pain in the ass, but it's the best I can do for now. If I could figure out the syntax the driver uses in the windows.ini file, I could probably write a batch file to do all this crap for me.

That's the price you have to pay in order to be "cool" I guess. Hopefully I'll figure out a way to get the VGA feature connector going at some point. I don't want the parts I bought for my VGA terminator to go to waste. I was pretty disappointed to find out that the feature connector only does 8-bit modes, and only up to 640x480. There's supposed to be an advanced feature connector, but I don't think I've ever seen a card that had one.