Today, I was reminded that at one point I had strong feelings on the issue of PS/2 versus USB for keyboards and mice, where I didn't like USB keyboards and my preferred mouse (or variety of them) was also a PS/2 mouse. However, these days I am entirely USB based for both keyboard and mouse and I don't particularly want to go back. What got me here is an assortment of issues, including the relentless march of time and 'progress' in the computing sense. Or, the short version, PS/2 is a de facto obsolete connector format.

Because PS/2 is de facto obsolete, increasingly many motherboards have one or zero PS/2 connectors; insisting on two or even one was clearly constraining my choices even back in 2015. I could have tried to keep using my 2015 favorite keyboard and mouse through PS/2 to USB converters, but I ran into issues with them that made me start to question the wisdom of that. In addition, new mice and keyboards were mostly or entirely USB (although there are probably mechanical keyboards that are PS/2 based). When I made my first foray into mechanical keyboards, it was with a USB mechanical keyboard, and that's continued to my current one. I also later changed my mouse to one that I'm now very fond of, and that again is USB based.

(This shift had happened by the time I put together my current work and home desktops; I didn't bother to specifically look for PS/2 ports on either of their motherboards.)

My pragmatic results are that USB has worked reliably for me here, more or less as expected; I don't do operating system development or, generally, shuffle USB things around or do weird USB stuff that could cause heartburn to Linux's USB stack. In addition, moving to USB has allowed me to switch to a keyboard and a mouse that I've come to believe are clearly nicer than my old keyboard and mouse. However fond I was of the BTC-5100C and its small size, I'm pretty sure that it had worse keyboard feel than my current mechanical keyboard. And the old plain three-button mice I used to use are clearly inferior to my current mouse.

(And the switch made selecting desktop motherboards much easier, since I no longer had to care about PS/2 port(s).)

USB is still more complex than PS/2 and is subject to fun issues from time to time. I mitigate some of these issues by connecting my keyboard directly to a desktop USB port, instead of going through a hub (and on my work machine, I think my mouse may also be directly connected).

Over time, the same shift has happened on our servers. Old servers used to have a PS/2 port, and we tended to use a PS/2 keyboard on them. Then we started getting some servers that were USB only, so we switched to USB keyboards in the machine room and lying around. Now I believe all of our servers are USB only, with no PS/2 left, and certainly I don't know where any remaining PS/2 keyboards we have would be. We may have thrown them out by now.

(Okay, I kept my PS/2 BTC-5100C keyboards and mice, so we still technically have some at work. I even have the PS/2 to USB converters for them, somewhere. If I really wanted to I could connect one up for a side by side comparison, although there's no real point; I'm not going back.)

All of this is unsurprising. Shifts in connector and interface technology have happened before over my time with computers. Disks have moved from SCSI to SATA (or IDE to SATA in some environments) and now toward NVMe; *-ROM drives moved from whatever it used to be to SATA and are now basically obsolete; AGP and PCI gave way to PCIe (with some digressions along the way). Keyboards and mice are different only in that we directly touch them and so I and others have strong opinions about what ones we want to use (and as a system administrator I get to reflexively worry about 'will it work even when there are problems').