by userbinator 5 hours ago
I don't think these machines achieved much popularity in China either, as standard PCs were far more common and compatible with the existing software base.
the keyboard and trackpad are internally PS/2.
Interesting that the PC influence is still there, although I'm pretty sure a MIPS doesn't have them on port 60h/64h, or indeed any I/O ports. I remember having a similar moment of surprise when I played around with an ARM VM and discovered it had a "VGA-compatible" GPU emulating an old ISA-class chip.
A decade’s worth of SGI machines combined MIPS processors with PS/2 keyboard and mouse ports.
To be fair to that there wasn't really any other viable mass-market interface that the keyboard manufacturers in China/Taiwan could standardize on. The PS/2 keyboard interface was backwards compatible with an AT keyboard through the user of a passive physical pin adapter. And USB didn't exist yet.
Oddly enough, the SGI Fuel (also the Tezro, I think) had PS/2 keyboard and mouse ports but also offered USB ports and support for HID devices in IRIX.
I have no idea whether the keyboard and mouse that shipped with those later SGIs were PS/2 or USB devices.
edit: IMO there was nothing wrong with preferring PS/2 to USB 20-some years ago. Higher theoretical refresh rate on the PS/2 mouse at that time and the PS/2 keyboard offered better n-key rollover, although I question whether any of that mattered one way or the other to an SGI owner
In x86 i386 world there was a good long overlap of ATX/MicroATX motherboards shipping with both PS/2 keyboard/mouse ports and also USB ports on them, starting from 1998 era Pentium 2/3 systems when USB first became commonplace and continuing until probably 2010 or so.
(author) My understanding is that they're wired into the AMD southbridge which provides them over memory mapped I/O.