VOGONS


First post, by vanfanel

User metadata
Rank Newbie
Rank
Newbie

Hello there,

I found an apparently nice modern computer for DOS usage:

https://es.aliexpress.com/item/1005003330185279.html

It uses a compatible GPU (Gen7 is supposedly still good for DOS, isn't it??), CPU has no L3 cache, and SBEMU works on it nicely so I even have SoundBlaster audio on it.

However, USB keyboards stops working correctly when I enter any program or game. For example, if I load the classic EDIT.COM, ALT and other special keys stop working, and in games like Doom, ENTER or ESCAPE are ignored so I can't start a new game, etc.

Also, some games like Prince of Persia exhibit small graphical glitches (in demo mode, since keyboard stops responding in game) in torches an other elements... I guess that could be because of the 2.2 GHz CPU.

But compatibility seems to be good! Dune and Dune 2 work nicely (only mouse control available), Duke Nuken 3D also looks and sounds good (without working keyboard input as I said), etc
It seems to have all the video modes required and working.

I contacted the manufacturer in Aliexpress but they claim that DOS compatibility is broken because of the presence of one USB 3.0 port. Does that even make any sense? I have other computers with USB 3.0 where keyboard works perfectly well on DOS.

So, any ideas? Or maybe should I return this computer? I got it specifically for DOS gaming as it seems to use compatible components (for example, in this thread: DOS on a modern PC, it's said that Haswell graphics are adequate / old enough)

Reply 1 of 4, by Falcosoft

User metadata
Rank Oldbie
Rank
Oldbie

CPU/GPU DOS compatibility is necessary but not sufficient. Keyboard/mouse emulation by BIOS can be problematic. DOS itself and DOS programs/drivers do not support USB devices natively. Your BIOS/UEFI has to emulate the proper PS/2 devices required by DOS drivers /programs. On more modern PCs it's not rare that this emulation is broken and it's only enough to enter BIOS and change settings.
I would say that a perfect DOS PC has classic PS/2 ports for both keyboard and mouse.
If your problem was mouse related then you could use the COM port for a serial mouse but for keyboard problems COM port is not the answer.
Maybe you should try to find a PS/2 header on the motherboard.

Website, Facebook, Youtube
Falcosoft Soundfont Midi Player + Munt VSTi + BassMidi VSTi
VST Midi Driver Midi Mapper

Reply 2 of 4, by vanfanel

User metadata
Rank Newbie
Rank
Newbie

So, is it true that USB3 is a problem for DOS compatibility? My understanding is that, if PS/2 emulation in the BIOS is correct, USB should work correctly even if it's USB3.
The computer has two COM ports, but I don't think there are serial keyboards or USB-to-serial adapters to use USB keyboards on it...

Well, in the end I will return the computer I guess.

Reply 3 of 4, by elszgensa

User metadata
Rank Member
Rank
Member
Falcosoft wrote on 2023-08-24, 08:39:

On more modern PCs it's not rare that [PS/2 device] emulation is broken

I wonder how Coreboot is doing on that front? On one hand not very many boards are supported by it but on the other hand at least it'd cut down on guessing about compatibility.

Reply 4 of 4, by mirh

User metadata
Rank Member
Rank
Member

I'd wonder how FreeDOS is doing with it if any?
Or any of the USB drivers perhaps?

Then putting aside the many possible UEFI voodoo "hopeful workarounds", did you try to tinker with XHCI pre-boot mode, XHCI Hand-off or Port 60/64 Emulation options in its settings? (I mean, idk about your potato pc, but even the latest greatest and shiniest motherboards should still have them somewhere)

pcgamingwiki.com