Golf-Ball Printer

n. The IBM 2741, a slow but letter-quality printing device and terminal based on the IBM Selectric typewriter. The 'golf ball' was a round object bearing reversed embossed images of 88 different characters arranged on four meridians of latitude; one could change the font by swapping in a different golf ball.

This was the technology that enabled APL to use a non-EBCDIC, non-ASCII, and in fact completely non-standard character set.

This put it 10 years ahead of its time -- where it stayed, firmly rooted, for the next 20, until character displays gave way to programmable bit-mapped devices with the flexibility to support other character sets.