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Open Source DOS Sound standards! (Developers)

posted by bretjohn Homepage E-mail, Rio Rancho, NM, 09.01.2013, 01:41

> Yes I know it emulate HW at low level and special VM drivers are needed.
Actually it doesn't necessarily take /special/ VM drivers, it just takes drivers for whatever elements the VM provides access to and isn't already virtualized (or isn't virtualized properly). What's virtualized is usually some subset of keyboards, mice, joysticks, disks, network cards, sound, USB hosts, serial, and parallel ports. Some VM's provide a lot of those different elements, some only a few. Of the different elements I've personally tried to any extent in different VM's (keyboards, mice, disks, and USB), all are problematic. I have a very difficult time believing the elements I haven't tried yet are going to perform any better than the ones I have.

> Do you know how hardware CPU Virtualization support helps the VM software?
Not exactly, but I do know that it's up to the VM to decide which peripheral hardware is virtualized. For the vast majority of users and applications, the limited number of virtualized elements they provide may be good enough. If the VM doesn't correctly virtualize the particular peripheral hardware you're wanting access to, you have to virtualize it yourself (without hardware assistance).

> What is the difference if VM runs on old CPU without HW virt. support and
> with it?
It doesn't matter -- all that matters is what the particular VM decides to virtualize for you. Whether it does it with hardware assistance or not is immaterial.

> If it also would help under d dos e.g. for IO or memory trapping or
> better/faster service handling...
It's conceivable that it could outside of a VM, though I don't know enough to say for sure. Even if it could, though, I personally don't think it's worth pursuing. Since it can't be used inside VM's, and VM's are what most people seem to be using these days, it doesn't make sense to spend a lot of effort on it. Solutions that /require/ special hardware, or that won't work in a VM as well as on real hardware (both old and new), aren't worth a large investment of time, IMO.

I don't know for sure about this either (it seems you know a LOT more about this stuff than I do), but I think the CoreBoot/SeaBIOS/UEFI route for "directly" booting DOS is going to be a virtualized environment too, probably not much different (at least in a practical sense) than the current VM's.

> Yes AFAIK it's not virtualized but I meant it just for real DOS.
Like I said, I'm not going to personally spend much effort exploring this, since I think it has such limited application. If you (or someone else) wants to figure it out and share your knowledge, I would certainly take a look -- especially if you could provide access to it through a common API.

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