IBM PS/2 Model 50

The machine

IBM's attempt to retake the architecture with a proprietary 32-bit bus (Micro Channel Architecture, or MCA) and an all-new chassis design. PS/2 also introduced VGA, the 1.44 MB 3.5" floppy as standard, and the round mini-DIN keyboard and mouse connectors that bore its name for the next twenty years.

Why it matters

MCA was technically excellent and commercially a flop — Compaq and the rest of the industry refused to pay royalties and built EISA instead. But VGA, the 3.5" floppy, and PS/2 ports won.