IBM 2741

(printer)A slow, letter-quality printing device andterminal based on the IBM Selectric typewriter. Theprint head was a little sphere resembling a golf ball, bearingreversed embossed images of 88 different characters arrangedon four parallels of latitude; one could change the font bychanging the golf ball. The device communicated at 134.5 bitsper second, half duplex. When the computer transmitted, itphysically locked the keyboard.

This was the technology that enabled APL to use anon-EBCDIC, non-ASCII, and in fact completely non-standardcharacter set. This put it 10 years ahead of its time -where it stayed, firmly rooted, for the next 20, untilcharacter displays gave way to programmable bit-mappeddevices with the flexibility to support other character sets.

单词	ibm 2741
释义	IBM 2741 IBM 2741 (printer)A slow, letter-quality printing device andterminal based on the IBM Selectric typewriter. Theprint head was a little sphere resembling a golf ball, bearingreversed embossed images of 88 different characters arrangedon four parallels of latitude; one could change the font bychanging the golf ball. The device communicated at 134.5 bitsper second, half duplex. When the computer transmitted, itphysically locked the keyboard. This was the technology that enabled APL to use anon-EBCDIC, non-ASCII, and in fact completely non-standardcharacter set. This put it 10 years ahead of its time -where it stayed, firmly rooted, for the next 20, untilcharacter displays gave way to programmable bit-mappeddevices with the flexibility to support other character sets.
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