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IBM PGA adapter

It's a wide mix ... here are some examples:

- My original DOS diskettes (DOS 2.1, DOS 3.3, etc.)
- Misc diskettes: (IBM Diagnostics, Exploring the PCjr, driver diskettes)
- Original program files: (Wordstar, Flight Sim, etc.)
- Diskettes that I did my work with
 
Re: IBM PGA adapter

mbbrutman said:
I think I have found an IBM Professional Graphics Adapter. It's three boards sandwiched together, taking up two slots. There are two connections to the bus, both designed for 8 bit buses. The output connector looks like CGA or EGA - 9 pin D shell.

Does anybody have documentation? I know they were very rare due to their cost, and there is no hope of finding the monitor. But being able to read the docs would give me an idea of what I need to look for.

Mike
Click to expand...

I had a PGA monitor about 6 years ago that I tried without avail to give
away on the classiccmp mail-list after many years of trying to find the adaptor for. IIRC it had a resolution in-between CGA and EGA, somewhat similar to RGBI. IIRC early Mueller books mentioned it and gave some specs. It had some built-in hardware perks related to 3d CAD I believe.
I might have some other info on one of my boxes, but it wouldn't be trivial
to find it.

Lawrence
 
An interesting thread.
I've been an IBM collector for some time and have many models , especially PS/2s. The box I'm posting this on is an upgraded PC350
my main computer. I have several IBM PCs but my favorite has an
Intel Inboard 386. I love the expressions when I turn it on and
scoffers see a PC running with a VGA monitor. It is a daughter-board
mounted on the original PC. There was also a memory expander card
for the mod but unfortunately I have yet to find one.

While I do have original configuration machines, I love the mods that
transcended the original limitations.

Lawrence
 
Terry Yager said:
Micom 2000 said:
While I do have original configuration machines, I love the mods that
transcended the original limitations.

Lawrence
Click to expand...

Oh, kinda like me, running MSDOS on my CP/M machine...

--T
Click to expand...

On a Dec Rainbow it was second nature. Was it Uniform that used to be able to do that ? An original simulator ? The Atari ST could run CP/M but that was really simulation, CP/M 68. Magic-Sac used actual Apple ROMS on an ST to run Apple-Dos. The maker was sued by Apple.
The C128 IIRC like the 'bow also had a second Z-80 processor IIRC.
 
PGA Card and display

PGA Card and display

I have both the IBM PGA display adapter and the 5175 monitor that goes with it. The display is in perfect condition, but is no longer functional. When I received the unit, the image displayed on the screen through the PGA adapter was distorted, so using some online documentation, I opened up the display and attempted to adjust the output. I successfully managed to clean up the picture, but after attempting to display some CGA graphics (which are emulated by the card), the display went dead on me. According to a repair guide on the internet, a capacitor in the power supply has likely gone bad with age and should be replaced. I have not messed with the monitor since, because I am affraid I will either electrocute myself, or damage the monitor in the process. Hopefully one day I will bump into somebody that is familiar with repairing these displays though.

According to several sources the 5175 monitor is identical to the 5154 with the exception of the electronics contained in the small metal box mounted in the inside of the unit. In theory the 5154 and 5175 electronics can be interchanged. I have not yet attempted to do this. I haven't had time to play with old computer crap for a good year now.

Lastly, some information on the internet claiming that PGA is TTL is incorrect. PGA and VGA are both analogue and have very similar pinouts. I think the only major difference has to do with the way in which PGA separates colour. I believe PGA uses composite, while VGA uses separate red, green and blue. I looked into building an adapter, and it looks relatively simple. But, since my PGA display is not working at the moment, I have no reason to do this. Converting a VGA monitor to work on a PGA card should be about the same thing.

To conclude my post, I would like to say that the PGA adapter is pretty much useless because there are no drivers available for it (unless some talented individual goes out of his/her way to write some). The 5175 display on the otherhand is quite nice, because combined with an adapter will allow you to display VGA graphics on your XT, AT without giving up the look of authenticity.
 
PGA signals

PGA signals

I can't read through all that crap right now. The PGA monitor (Princeton also offered one) DID use analog signals. How else would you get 256 colors. I don't know if it could put them all on screen at the same time though. Use it with a multisync - new ones may even work, because it's resolution was 640 x 480, so it's got to be near the bottom of vga in terms of sync rates. I have...well kinda...something similar. A Vermont Microsystems card with an 80186 onboard (the PGA had an 80188?). There's an interesting story about this company on the net somewhere. They took Autodesk to court over the use of some triangulation algorithm, and won. Mine takes up 2 slots (I thought the PGA took up 3?).
You need special drivers. I don't think it was compatible with the CGA/MDA, and came out prior to EGA. Probably only ran high end stuff, scientific/cad whatnot. Quite a find. I'm jealous too.
 
I coded a bunch of software for the PGA/PGC back when it was the latest and greatest. So here's a few tidbits for you from memory.

It had no BIOS support, except for a very basic CGA compatability mode that required throwing a hardware switch on the board--which never happened. It was usually used to drive a second display on a system, the main display would be a standard card like an MDA or HGC card.

There were some sample routines provided on disk, with some sample source code for IBM compilers. I built my own assembly routines then called those from MS Fortran or Turbo Pascal. You could put all 256 colors onscreen simultaneously. The resolution and color depth made it the equal of workstation display systems costing tens of thousands of dollars at the time, like the ones for Sun or Apollo (my favorite at the time.) Most professional programs intended for use with the PGC included their own software. Mostly CAD/CAM stuff. I was doing scientific visualization software on ours.

It was far more flexible and faster than VGA. I felt VGA was quite a step down when it came out, with its limited functions and limited memory window (the PGC took 2K of system memory, but you didn't talk to its memory, you passed it commands and it talked directly to all of its graphics memory while processing the display list you gave it.) Coding sophisticated graphics on the PGC was far more straightforward, more expressive thanks to a lot more hardware functions, and took a lot less overhead than VGA. But VGA was cheap. Personally I was hoping for wide acceptance of the TI 34010 and 34020, which were more like the PGC from a programmer's standpoint (and even more so, not to mention cheap, but not as cheap as a VGA fixed-function processor.)

The displays that could be programmed with the PGC made VGA look like garbage. Only when 8415 graphics came out did things start to look decent again. I still have some VGA software I ported from PGC. The look of it makes me gag compared to how it looked on PGC. Only the Amiga's HAM mode and the 34010 card produced as nice a display (almost as nice on the Amiga, even nicer on the 34010 with the right monitor.)

So, unless you're really into coding graphics and don't care how useful it is to others, there's not much point to one now.

Though turning up one of those 34010 boards might be worthwhile... ;)
 
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saundby said:
It had no BIOS support, except for a very basic CGA compatability mode that required throwing a hardware switch on the board--which never happened.
Click to expand...
My card got all the jumper present from factory, except for the light-pen interface (it was never supported by the firmware anyways).
 
saundby said:
So, unless you're really into coding graphics and don't care how useful it is to others, there's not much point to one now.
Click to expand...

Thanks for the info on the PGC card, I have one of the cards and monitor and have played around with it occasionally.
There were a couple of in depth articles about the card in several of the PC magazines. I scanned these in awhile
back lmk if anyone wants a copy. One thing I have been looking for is the demo diskettes that came with the PGC.
One of the articles mentions a demo diskette and also a graphics toolkit, which I've never seen.
 
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