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Thread: Via Mini-ITX EPIA as a retro DOS machine: setting up UMBs?

  1. #31
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    Quote Originally Posted by Chuck(G) View Post
    Does the BIOS setup include an option for using USB floppy under DOS as the A: drive? On my HP Neoware thin clients, it exists and works pretty well for standard 3.5" DOS formats.
    The only explicit "legacy USB" option in the BIOS is keyboard emulation, but after doing some experimentation it looks like there is a BIOS-level emulation for a floppy. But I have to say the implementation leaves something to be desired.

    It turns out I do get a working A: drive if I plug in the floppy before booting and don't have a memory manager loaded, at least with the normal greedy switches. With UBMPCI or EMM386 disabled poking around with Checkit there's a new 32k ROM signature that shows up in upper memory from D200-DA00h when the floppy drive is plugged in. (Oddly the PXE ROM that started at CC00h before also seems to go away? Checkit instead sees a 24k gap between the end of the video ROM and this new ROM that shows a mix of two 8k empty blocks and one 8k region of high RAM.(???)) So... yeah, I guess it can emulate a floppy, but it needs a shedload of upper memory to do it?
    Last edited by Eudimorphodon; February 4th, 2020 at 01:40 PM.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  2. #32
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    Quote Originally Posted by pcdosretro View Post
    When I had a CMI8738 soundcard I used it in an Intel chipset PC and later an AMD chipset PC. It worked on both but I do recall having to patch SETAUDIO.COM because it wasn't initializing the card properly based upon the spec, once I did that everything worked fine.
    Alas figuring that out is probably significantly beyond my abilities. Poking around Vogons posts it seems like most end up with tantalizing hints the card *can* work but they all seem to end in about the same boat I'm in, IE, it'll do Adlib and everything else is either broken always or worked once and never did again.

    I used the driver set that the guy who does "Phil's Computer Lab" has on his webpage, maybe I'll poke around and see if any of the other downloads for setaudio.com have a different checksum.

    The one thing I'll say about the VIA's built-in sound is it has *worked* with everything I've tried so far. The 40k of conventional RAM the FM sound emulation needs is the main bummer. Well, that and no game/midi port.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  3. #33

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    Quote Originally Posted by Eudimorphodon View Post
    Alas figuring that out is probably significantly beyond my abilities. Poking around Vogons posts it seems like most end up with tantalizing hints the card *can* work but they all seem to end in about the same boat I'm in, IE, it'll do Adlib and everything else is either broken always or worked once and never did again.

    I used the driver set that the guy who does "Phil's Computer Lab" has on his webpage, maybe I'll poke around and see if any of the other downloads for setaudio.com have a different checksum.

    The one thing I'll say about the VIA's built-in sound is it has *worked* with everything I've tried so far. The 40k of conventional RAM the FM sound emulation needs is the main bummer. Well, that and no game/midi port.
    Try the attached setaudio.com which I patched for my CMI8738 soundcard. I recall some games originally hung in a loop because one of the CMI8738 registers wasn't initialized properly which caused the DMA address and count registers to not be updated during playback which some games rely on.
    Attached Files Attached Files

  4. #34
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    Quote Originally Posted by pcdosretro View Post
    Try the attached setaudio.com which I patched for my CMI8738 soundcard.
    Thank you for posting this. I tried messing with various aspects of the config for about an hour and while there is some "change" it's still not working with most software. Strangely digitized sound in "Quake" suddenly works perfectly, but everything else I tried still crashes when trying to use it. ("Doom" crashes hard before even going to graphics mode, Jazz Jackrabbit is able to play a few seconds of FM music before it crashes in the opening cinematic, etc.) Adlib is still fine. I assume it must be some chipset-level incompatibility.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  5. #35

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    Really enjoying your adventure down memory lane. Back in the day I would hand look at the memory map for umb space, picking my own memory regions for inclusion with himem and emm386. And the MS versions of these were best for compatability as IBM's DOS was always slightly different.

    On the same oldskool site linked above there is a floppy emulator that allows you to write an image and then play it back, but I think your usb floppy works and that your umb was just overwriting the rom. You can always do what we did--copy the disk to the hard drive and then use the subst command to subst a: for c:\game. It worked pretty well for most games. And you could even subst b: for c:\gamedisk.2 so you didn't even have to swap disks anymore.

    And for some games you could just copy all the files to one directory and just run it from there.

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