Tracking down "why is the antique system suddenly slow". Power went out, system came back up fine, everything but the one ancient but vital app is fine. Dig, dig dig, there's this old dot matrix printer in another room (because it used to be loud and annoying) that no on has fed or looked at in years.

It finally died with that outage, and it not accepting data was the problem. It had cheerfully printed the ribbon through, then fed out the rest of the box of paper it had, and that might've been several years before i saw it.

The roller the paper was supposed to ride had been eroded. The metal rods the print head rode on had a perceptible bump at the ends of the normal stroke.

The fix was a little dongle for the printer port that held the appropriate "i'm alive" lines up. hardware /dev/null. I'm thinking it was 25 pin rs232 because I remember a lot of cussing over it.