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Thread: D-Link "Plus Card" - info needed

  1. #1

    Default D-Link "Plus Card" - info needed

    This card came in my IBM PS/2 Model 25 I got a few years back:


    IMG_4838.jpg


    It's a D-Link "Plus Card". I always thought it was an EMS board, but I don't think that's what it is after attempting to use it (I have the D-Link utility for it, which was still on the HardCard 20 that was also installed in the machine). I popped it in my Compaq Portable to try it, and it seems to extend the base memory? After I loaded the driver, I opened up CheckIt, and it said I had 704KB of base memory! Windows 2.03 and 3.0 wouldn't have it though; they both crashed on startup with the driver loaded. Windows 1.01 didn't mind it though! I had about 80KB more than usual free in Windows 1.01. So I don't know if maybe there is a bad RAM chip on the card, or if Windows 2.XX and 3.0 just don't like it.

    Does anyone know anything about this card? I couldn't find anything about it online.
    Compaq - “It simply works better”

  2. #2
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    That is an odd memory board. It looks like it can't hold more than 320K, which does suggest it was meant to fill UMB above 640k.

    There are no jumpers, which makes it dependent on having a driver loaded first. While that is awkward, trying to extend base memory rather than just adding UMB blocks requires jumping through hoops and reconfiguring on the fly if you are using VGA video.

    The problem is with VGA, unless you restrict yourself to color text mode or CGA graphics, VGA uses the A000-AFFF memory range, right after the end of the 640k.

    I recall some other DOS drivers that either used chipset memory mapping or used extra mapped video memory to get more base memory, but it would have to disable itself and switch back to 640k whenever using a VGA graphics program.

  3. #3

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    “Odd” is definitely the right word!

    Interesting about VGA. However, the machine I tested this in was a Compaq Portable, which is CGA, so there shouldn’t be any issue there.

    I’ll use it if I can figure out why it makes Windows crash. Windows in particular is one of the programs that could benefit from this card the most.
    Compaq - “It simply works better”

  4. #4

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    I've thrown this card in my newly-built IBM XT for now so I can play with it some. It works just fine under Windows 1.01 (as mentioned above).

    However, I can't get it to give me more than a 64KB increase. A manual would be really helpful, but I literally can't find any evidence of this card's existence other than the one I have! I was also able to use some of the RAM chips I pulled from my XT for the 640KB mod, so this card is fully-populated now.

    It's a damn good thing the utility was still on the hard drive that was in the machine this card came with, or this thing would be totally useless!
    Compaq - “It simply works better”

  5. #5
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    If you post the utility, perhaps someone could help figure out how else it can be used. (And it would help anyone else in the off chance they found another card like this).

    I am wondering if this card could also fill some amount of base memory, such as bringing a 512k system to 640k, but that would problematic if it was software controlled.

    Were there any other possibly related utilities on the hard drive, such as a print spooler?

    A lot of late dos-era programs make all kinds of assumptions about memory usage. Many assume the user always has at least 640. It does not surprise me that many would freak out if they saw more.

  6. #6

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    Here's the only two files related to it I could find:

    DPLUS.zip

    There is "DPLUS.EXE", which is the main utility, and then there's "HIEXEC.EXE", which I don't quite understand the purpose of, or how to use it.
    Compaq - “It simply works better”

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    HIEXEC, if the information returned by it is correct, will load a program in Segment C, D, or E. Presumably nothing else can be loaded there.

    DPLUS.EXE had very little within except for lots of text and long blocks of zeros. Two blocks both of about 17k of zeros except the first block also has the letters KOKO in it. That suggests it may be paired with some form of overlay system that inserts the needed code. The text talks about detecting memory segments in use or free and expanding the memory to 704k and doing something with addresses to 1024k. Check for any files with the same date in the same directory as the EXEs that were copied.

    Need a manual to get the correct syntax to set it up. The executable refers to a Pivitronic Plus Card but I can't find any relevant Pivitronic.

  8. #8

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    Guess this wasn’t a very popular expansion, huh?

    Anyways, thanks for having a look at the files for me. Anyone feel free to upload them anywhere you like. They definitely need to be preserved.
    Compaq - “It simply works better”

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    Unfortunately, saving these files won't benefit anyone since the executable program code is not included. Big banks of nulls will do nothing. Somewhere, maybe on the disk, maybe on install media, there should be additional files that include the executable code. Might be overlays; might be a patch run during install. I looked at a disassembly and didn't see any call to an overlay file so I can't tell you what file to look for.

    I had hoped to find at least a review of the card to figure out how useful it was. I remember a number of cards that did specialized memory expansion in conjunction with network adapters and redirectors. Slightly cheaper than an EMS card but really only useful for a 5150/5160 being networked.

  10. #10
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    Quote Originally Posted by krebizfan View Post
    Somewhere, maybe on the disk, maybe on install media, there should be additional files that include the executable code. Might be overlays; might be a patch run during install.
    Well, when I tried to run the program it at least starts to run, although it obviously complains that no card is installed, and exits.

    Compaqportableplus, are these the only two files you copied from that other computer? Could you try just running through all visible options in the dplus application and see if complains about anything missing?

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