Decided to give the nice, big Unicomp keyboard (an IBM Model M in all but name -- and maybe that as well, since the bottom is still marked "MODEL M" from the mold) a try, after a disassembly and cleaning so thorough that I wasn't entirely sure it would still work after I got it back together.
It does. I'm using it.
There's a little bit of desk-cleaning yet to do, and I don't have the computer back in the usual location, but when it's done (or sufficiently cleared -- an open workspace is a process, not an end-state), I'll take a picture to share. I'm unlikely to ever achieve 5S levels of orderliness but it's better to make the attempt than to wallow in bad habits.
3 months ago