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Lou - N2MIY
December 21st, 2008, 07:16 PM
Folks,

Is there a way to force a VGA card to work like (look like to software) an MDA/HGC or CGA card?

I picked up an NIB 1987 vintage logic analyzer adapter for a PC that was intended to be used with an MDA or HGC video adapter. I have it working in a dos 6.22 P5200 with a diamond stealth 3D 2000. However, only the text based operations work with the software it came with. When I try to use the mode where it can display timing diagrams (which needs graphics support) I get an error that it can't find the graphics adapter.

Any thoughts are appreciated.

Lou

patscc
December 22nd, 2008, 12:17 AM
That's a PCI bus card, isn't it ?
Sounds like the software you're trying to run is DOS-based.
Just out of curiosity, are you trying to run it in a DOS-box( running the DOS app in Windows ) in a fairly recent pc( well, anything with a PCI bus) ?
patscc

Lou - N2MIY
December 22nd, 2008, 03:07 AM
Yeah, the video card is PCI. The computer has PCI and ISA slots. It supports plug and play ISA, so I had to use the plug and play configuration utility to set the I/O port addresses for the (non PNP) 8 bit ISA logic analyzer adapter.

I'm running real MS dos 6.22. No windows is involved here. Yes, the software (circa 1987) is dos based. It all runs fine (I've got the logic analyzer connected to a test circuit to stimulate the inputs) except the portion of the software that graphically displays the captured data. Fortunately, the captured data can be displayed in tabular form if we can't get the graphics dependant portion going.

Lou

patscc
December 22nd, 2008, 01:58 PM
Try typing mode co40 or mode co80 at the dos prompt before you load the app, see if that makes a difference. What you really is a utility that tells the graphics adapter to start up as cga. I have some for ATI cards, but none for Diamond. Anyone out there have one ?
patscc

NobodyIsHere
December 22nd, 2008, 02:54 PM
Hi!

I seem to recall being able to do exactly what you describe. It has to do with VESA modes or something like that. Maybe you can set your MB BIOS to expect a MDA/Herc and that might get it to work. There may be a DOS utility which can force the VGA to appear like a MDA/Herc on a VGA monitor. It will probably involve double scanning of some sort to get the monitor syncs to line up.

Probably you are going to get your best results by just using an XT clone though. Fortunately they are pretty inexpensive if you stick with the no-name stuff. Shipping a monochrome monitor does not sound appealing though.

Best of luck! Thanks and have a nice day!

Andrew Lynch

Chuck(G)
December 22nd, 2008, 04:38 PM
Try running the attached program at the DOS prompt. It puts the VGA into double-scan mode and sets CGA mode 2.

Since I don't know what test your program uses to determine display type, it may not fool the program. If not, let me know and I'll keep cogitating on it.

Lou - N2MIY
December 22nd, 2008, 05:04 PM
Guys,

I tried MODE CO40, and the screen went into 40 column mode, but the software still gave the same error. MODE CO80 put it back in 80 col mode and yields the same error. I also tried setting the bios to mono, then CGA, and got the same results.

I'm eager to try the setcga. It might be what the doctor ordered!

Lou

JohnElliott
December 23rd, 2008, 09:04 AM
The problem is, I don't think any modern VGA card will emulate the Hercules at a hardware level. And you need hardware-level emulation, because there was never any BIOS support for the Herc's 720x348 graphics mode. Your program may, for example, be checking for a vertical sync pulse on bit 7 of port 03BAh, which is only present on a real or emulated Herc.

The Paradise EGA chipset could emulate a real Herc, and I think the early Paradise VGA chipsets could as well; you'd use a DOS-based utility to set the emulation.

Chuck(G)
December 23rd, 2008, 09:54 AM
Yes, but many VGA cards can emulate CGA and MDA (but not MGA).

JohnElliott
December 23rd, 2008, 11:34 AM
The impression I got from the original post was that the software only supported Hercules graphics.

Chuck(G)
December 23rd, 2008, 02:34 PM
The impression I got from the original post was that the software only supported Hercules graphics.

If that's the case, yeah, then there's a problem. If it'll work with CGA, then there's hope. It isn't clear (between his first and second paragraphs) if CGA is an option--I think that's confusing people a bit.

On old programs like this, sometimes there's a configuration file (.CFG, .INI,...) that indicates what sort of graphics adapter is expected.

Lou - N2MIY
December 23rd, 2008, 03:57 PM
Folks,

I tried the setcga, to no avail. So, I tried to re-educate (it's been a long time) myself on the difference between MDA/HGC/CGA. If support for graphics is truly required, then an MDA wasn't going to cut it. I must need HGC or CGA to make this work. I would guess that the program is trying to write to B000h or B800h, which are the two areas where HGC video data is stored.

The one configuration file where the program stores user preferences is not intelligible. I guess I should look at it with a hex editor for good measure. Also, there's no source code on the disk that came with the logic analyzer.

This diamond stealth 3d 2000 has a S3virge chipset, which may be able to emulate the HGC. I did find a dos TSR for this card, but running it did not fix the situation.

I do have a Paradise VGA card, with the original dos software that came with it. It is in my very first PC (a clone bought in 1990.) I'm going to give that a try tonight.

I still have an XT, but I haven't run it at least 10 years. I stole the MFM hard disk out to put on a pdp-11/23. (Is it a travesty to steal parts from one vintage machine to use on another?) I just opened it up though, and lo and behold it has a 1984 original Hercules card. However, I no longer have any TTL monitors.

I'm truly unsure if CGA would really work. The manual (of which english was not the author's native tongue) lists as the requirement "One Monochrome/Graphics Card." Since this was made in 1987 I assumed that CGA was supported.

I'll report on my progress later this evening... All of your ideas have been really helpful and are greatly appreciated!

Lou

Chuck(G)
December 23rd, 2008, 04:03 PM
Can you make enough of this program (it can't be too large for 1987, after all) available to those of us who'd like to take a poke at it?

Lou - N2MIY
December 23rd, 2008, 05:12 PM
Folks,

Here's the entire contents of the disk that came with the logic analyzer. I should mention that it was made by Axelen Industrial Inc. (Taiwan) and is model 24100A. A very simple 8 bit card plugs into the ISA bus and a cable connects it to an external box. The external box has 8255s, memory, and lots of 7400 series glue. Three 8 bit pods connect to this box. It's really el-cheapo (compared to an HP/Tek/Biomation) and looks like something that might have been in the Jameco catalog back in the day...

Lou

Terry Yager
December 23rd, 2008, 06:12 PM
Even in ESL-speak, I would interpret
The manual (of which english was not the author's native tongue) lists as the requirement "One Monochrome/Graphics Card." Since this was made in 1987 I assumed that CGA was supported.to mean, "Monochrome or Graphics Card," i.e. MDA/CGA, especially if the card is an early one, from a time when those were the only two choices (widely) available.

--T

Terry Yager
December 23rd, 2008, 06:22 PM
I don't know if it's pertinent here but, I have an old ROM burner with a similar 'problem', it only works with MDA or CGA. In my case tho, it's due to a memory conflict. The card/software grabs a 64K buffer that is in the same address range that later video standards use for their VRAM, hence, conflict. It may be a simple fix for someone who speaks 8086 assembler, but beyond my skillz. Much easier for me to just keep it installed in a machine with CGA, since I only actually use it once inna coon's age.

--T

Chuck(G)
December 23rd, 2008, 07:32 PM
I just tried the disk on a couple of machines (you don't need the logic analyzer hardware attached to see the display issues).

Indeed, the thing seems to have been written for an MGA/Herc card. The logic trace display fills the screen from corner to corner. Trying to see a trace on a CGA produces an error message complaining about the hardware. Even the text displays are partially dependent on the MGA display buffer location. If you hit F1 for help and then ESC to exit, the display stays up.

The gotcha in all of this is that a Herc graphics display is what, 720x350? You could try to map it to a VGA 600x800 maybe, but that'd take some serious code plugging.

This may be a dead-end, but let me think on it a bit.

Lou - N2MIY
December 24th, 2008, 07:36 AM
Guys,

Thanks for all your help. JohnElliot's suggestion of using a Paradise VGA card has done the trick! Indeed, this software was MDA/HGC card specific.

I pulled the Paradise card (actually some knockoff called an NT-200B, but it used the right WD chipset) from the other computer. It had a utility called VGA1024.exe, that allowed me to set the card to HGC mode. Now it works!

Thank you Chuck for also confirming the software was HGC specific on your own hardware.

Now I just need to find another of these Paradise cards to make the other machine whole again (like Terry, it has my eprom programmer in it.)

Thanks again everyone!

Lou

Druid6900
December 24th, 2008, 06:40 PM
What's the chipset?

I might have a video card around with the same chipset on it.

Lou - N2MIY
December 25th, 2008, 06:44 AM
The NT-200B card had the WD90C00 chipset. I actually still had the manual for it and the 5-1/4" floppies (which still worked and I backed up.) Although it fits in an AT slot, it can be set to work in an XT slot (even in an XT!). Looks pretty versatile. I need to keep my eye out for some more at hamfests this coming year.

Merry Christmas!

Lou

NobodyIsHere
January 2nd, 2009, 02:22 PM
Guys,

Thanks for all your help. JohnElliot's suggestion of using a Paradise VGA card has done the trick! Indeed, this software was MDA/HGC card specific.

I pulled the Paradise card (actually some knockoff called an NT-200B, but it used the right WD chipset) from the other computer. It had a utility called VGA1024.exe, that allowed me to set the card to HGC mode. Now it works!

Thank you Chuck for also confirming the software was HGC specific on your own hardware.

Now I just need to find another of these Paradise cards to make the other machine whole again (like Terry, it has my eprom programmer in it.)

Thanks again everyone!

Lou

Hi! I am glad this ended on such a happy note! Is anyone aware of similar MSDOS programs for Cirrus and/or Tseng chipsets?

My guess is that these programs such as VGA1024.exe are highly chipset and card dependent.

Thanks and have a nice day!

Andrew Lynch

Druid6900
January 2nd, 2009, 07:35 PM
Ok, seems I have a Brilliant Technologies 16-bit ISA card on my site with the WD90C00-JK chipset on it.

It has 256K and can be upgraded to 512K with 8 x 4464-8 chips.

I haven't had a chance to look at the ones I DON'T have on the site yet, but, I will, over the next few days.

Lou - N2MIY
January 2nd, 2009, 07:39 PM
Let me know if you'd like me to send a copy of the VGA1024.exe utility. You could try it on that card.

Lou

Druid6900
January 3rd, 2009, 11:14 AM
I was under the impression that you were looking for a card with that chipset for one of your machines.

Did you want me to test it out with that software? If so, send me the file as an attachment in PM.

NobodyIsHere
January 3rd, 2009, 11:36 AM
Hi Richard! yes, I bought a couple of VGA cards with the Paradise chipset on them for this purpose. I used to have one of these cards and that is why I remember doing this. However, I lent that computer to a friend of the family who was in college and it was destroyed by lightning :-(

It was a great card though. It seems to me that other VGA ISA cards had DOS utilities similar to the Paradise VGA1024 but I can't seem to find any. Have all the free driver sites on the internet disappeared?

Thanks and have a nice day!

Andrew Lynch

patscc
January 3rd, 2009, 01:46 PM
http://www.drivermuseum.com/
http://www.oldapps.com/list_drivers.php
http://oldfiles.org.uk/

for starters

patscc