DOS ain't dead - VDMA8.EXE the DDMA master emulator

RayeR

CZ,
29.12.2025, 07:45

VDMA8.EXE the DDMA master emulator (Announce)

Another interesting project based on SBEMU has appeared. It's just a strip down to minimal function of DDMA master emulator that can cooperate with PCI DDMA slaves. In this case the ITE8888 PCI to ISA bridge. Similar concept was done tens years ago by Yamaha - theirs DSDMA.EXE that I mentioned there about.
Maybe it could be accomodated also for others PCI sourdcards that supports DDMA. It simplifies things that there's no need of real soundcard drivers and other emulation stuff - may result in lower latencies, no sound stuttering, etc...

https://www.vogons.org/viewtopic.php?t=109297

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DOS gives me freedom to unlimited HW access.

Japheth

Germany (South),
29.12.2025, 09:32

@ RayeR

VDMA8.EXE the DDMA master emulator

Post reply

> Maybe it could be accomodated also for others PCI sourdcards that supports
> DDMA. It simplifies things that there's no need of real soundcard drivers
> and other emulation stuff - may result in lower latencies, no sound
> stuttering, etc...

Hm, remembering the history of VDMSOUND and DOSBOX I'd say full emulation wins in the long run...

The "sound stuttering" of SBEMU/VSBHDA is (most likely) caused by incomplete ISA DMA controller emulation - the index/count registers of the DMA channel are updated "occasionally" only (on sound hardware interrupt, which is usually each 2-3 ms; enough for games, but may be a problem for "hard core" SB applications like demos ).

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MS-DOS forever!

RayeR

CZ,
03.01.2026, 16:50

@ Japheth

VDMA8.EXE the DDMA master emulator

Post reply

> The "sound stuttering" of SBEMU/VSBHDA is (most likely) caused by
> incomplete ISA DMA controller emulation

Could it be improved in sw or is there some HW limitation?
I can understand that modern PCs are not realtime, with non-deterministic timings...

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DOS gives me freedom to unlimited HW access.