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First post, by darry

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Sorry if this is not the most appropriate forum, but it felt like the best place for this, since the PC is newer than the affected game .

I have a "retro" PC (Pentium 3) on which I use a mechanical USB keyboard . This usually works fine in DOS thanks to the BIOS routines for legacy keyboard emulation .

Doom, Duke Nukem 3D and others work fine under DOS too. BUT, when I tried Jazz Jackrabbit, I realized that any time a key is pressed, the animation starts to stutter . I plugged in a spare PS/2 keyboard (did not even bother unplugging the USB one), tried using it instead of the USB one and everything worked fine .

Moral of the story : PS/2 keyboard emulating BIOS code is not always perfect and having an actual PS/2 keyboard is better .

Last edited by darry on 2020-09-13, 02:50. Edited 1 time in total.

Reply 1 of 1, by darry

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darry wrote on 2020-09-13, 01:47:
Sorry if this is not the most appropriate forum, but it felt like the best place for this, since the PC is newer than the affect […]
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Sorry if this is not the most appropriate forum, but it felt like the best place for this, since the PC is newer than the affected game .

I have a "retro" PC (Pentium 3) on which I use a mechanical USB keyboard . This usually works fine in DOS thanks to the BIOS routines for legacy keyboard emulation .

Doom, Duke Nukem 3D and others work fine under DOS too. BUT, when I tried Jazz Jackrabbit, I realized that any time a key is pressed, the animation starts to stutter . I plugged in a spare PS/2 keyboard (did not even bother unplugging the USB one), tried using it instead of the USB one and everything worked fine .

Moral of the story : PS/2 keyboard emulating BIOS code is not always perfect and having an actual PS/2 keyboard is better .

Found a workaround. Using the drivers from here : http://www.bretjohnson.us/ fixed the issue completely in Jazz Jackrabbit .
All I needed to do is

a) Download and unzip http://bretjohnson.us/programs/usbdos.zip
b) Create and run a small batch file that invokes usbuhci.com and usbkeyb.com in sequence
c) Confirm that I wanted to run usbuhci.com even if I have legacy keyboard support enabled in BIOS (running usbuhci.com kills the keyboard in DOS, but running usbkeyb.com re-enables it, hence the batch file).

After that, Jazz Jackrabbit runs fine on my system with a USB keyboard .
The drivers have a rather large memory footprint, but they load high automatically if they can, which they did on my system .

EDIT: I used usbuhci.com , because my machine has a UHCI USB controller, so anyone with an OHCI USB controller would need to use usbohci.com instead .