kaputnik wrote on 2024-05-30, 07:33:

dionb wrote on 2024-05-30, 06:02:

kaputnik wrote on 2024-05-29, 09:39:

That could be extended to KVM switches and other peripherals fed by the PS/2 port aswell. I wouldn't worry too much when plugging in a single keyboard no matter how old it is, but with some KVM switch configurations etc, power draw might become an issue 😀

KVM switches tend to be powered themselves. I've had the opposite experience - a KVM switch that was extremely flakey with an IBM Model M but worked fine with anything more modern / less thirsty.

Many (if not most) KVM switches with external PSU have the option be powered by the computer's PS/2 keyboard port aswell. Nice to avoid an additional wall wart when possible, and having the KVM switch powering on/shutting down with the computer(s) when they aren't running 24/7, hence the interest for their consumption 😀

Can you recommend a KVM Switch? I searched and all I found were ones that assumed USB devices and HDMI monitors, but of course my retro rigs (I have a second I'm bringing back to life) both use PS/2 and have a VGA port for monitors (one of my comps has a graphics card with a DVI port... interesting that standard VGA ports are still around but DVI isn't. That's kinda weird).

I don't know what country you are in, but if you plonk around at thrift stores in Murica, it's fairly easy to find old OEM PS/2 keyboards and the older USB ones from the early 2000's that have minimal bells and whistles.

EdmondDantes wrote on 2024-05-30, 08:06:

kaputnik wrote on 2024-05-30, 07:33:

dionb wrote on 2024-05-30, 06:02:

KVM switches tend to be powered themselves. I've had the opposite experience - a KVM switch that was extremely flakey with an IBM Model M but worked fine with anything more modern / less thirsty.

Many (if not most) KVM switches with external PSU have the option be powered by the computer's PS/2 keyboard port aswell. Nice to avoid an additional wall wart when possible, and having the KVM switch powering on/shutting down with the computer(s) when they aren't running 24/7, hence the interest for their consumption 😀

Can you recommend a KVM Switch? I searched and all I found were ones that assumed USB devices and HDMI monitors, but of course my retro rigs (I have a second I'm bringing back to life) both use PS/2 and have a VGA port for monitors (one of my comps has a graphics card with a DVI port... interesting that standard VGA ports are still around but DVI isn't. That's kinda weird).

Used a fair amount of different VGA PS/2 KVM switches through the years, my favorite by far is the Black Box Servswitch Wizard SW652A. Works with everything you throw at it, doesn't degrade image quality, does high resolutions/refresh rates, passes PS/2 mouse scrollwheel through, emulates serial mouse, etc, etc. There's really nothing I don't love about it, except maybe the physical size. It's quite large to be a desktop KVM switch of its time. There's a lot of air inside though, it can easily be modded to less than half the size, which I did with mine.

Check the manual for more specs/details. Oh, and that's another thing, Black Box' documentation is in a league of its own. The manual even contains diagrams of the special cables/adapters it uses, in case you want to make your own 😀

Remember that VGA had been around for decades, while DVI became something of a parenthesis, when HDMI and DP launched. If I'm to guess, there's a lot more hard/expensive to replace VGA equipment than DVI ditto in use. It could be compared to ISA vs VLB, where the former survived its short lived successor after PCI launched. Also, it's easy to convert DVI using cheap "dumb" adapters. Either you can use the digital signal with HDMI equipment, or the VGA signal most DVI sources also embed with VGA equipment.

There are a few issues here.

The first is that USB keyboards in general were kind of flaky in the early days of USB even at the time. That definitely has not improved when trying to hook up a *modern* USB keyboard to an older system with USB. I have an Abit KT7A motherboard in my retro system that has USB 1.1 ports. I always had issues with USB keyboards back when this board was new and stuck with PS2 (a Model M) up until I stopped using it as my daily PC. Now that I've turned it into a retro gaming PC, I picked up a used Corsair K70 in silver aluminum to match my case aesthetics and it's got the same type of issues I remember, plus more.

The biggest issue is that there seems to be some limitation in the USB 1.1 spec (I don't know if it's power or speed) that forces the keyboard to revert to "BIOS" mode when in Windows. (Note that this is different from the BIOS mode *in the BIOS*; it's the keyboard's own BIOS mode.) I've checked the drivers and they're working fine. The keyboard itself works, but in BIOS mode it's at its lowest polling rate and does not support ten-key rollover. Now, may not be that big of a problem for most people but I know the limitation is there and it might matter in some games (I haven't installed too many yet). But it also means the damn scroll lock LED blinks at me constantly.

Doesn't happen in DOS. Not sure why. Just Windows.

Also, USB keyboards in general will kind of turn on and off throughout the bootup process. This is something I remember with older USB keyboards too. On some older systems, they wouldn't turn on at all until your OS loaded a driver for them. My motherboard luckily has a setting where I can select between BIOS/OS for USB keyboard detection. That means I can use the keyboard in the BIOS and in DOS, but I can't use it on my bootloader screen - it's off at that point.

PS2 keyboards don't have these issues. I remember that for a long time, USB keyboards were kind of considered persona non-grata for real hardcore users; it took a while before the keyboards, USB itself and motherboards were all designed in such a way that you could rely on a USB keyboard actually being fully functional all the time.

So honestly, unless you just want a particular aesthetic like I did and are prepared to live with some flakiness/less than perfect functionality, I would just get a PS2 keyboard. That's probably going to limit you to Unicomp or something used, or potentially new old stock. I bought my Lexmark Model M NOS back in the day, and I bought a Compaq rubber dome silver plastic PS2 keyboard a while back for this same computer that was also NOS. Honestly, I may just go back to that, although I still have a hard time dealing with the feel of rubber domes. (But hey, it is period accurate!) But the point is, you can still find stuff NOS if you look. Keyboards were real commodities for a while.