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2017-12-01 8:51 GMT+02:00 Hakki Dogusan <>:

> I think these magic numbers come from printer column sizes;
> normal mode:80 ch, condensed mode:132 ch.
> (for continuous form dot-matrix printers)

Older than that. In the 1960s, typewriters could do 8 inches wide
(leaving ¼in margins for the sprocket holes), giving 80 characters
at 10cpi (known as pica) but some typewriters did 96 characters
at 12cpi (known as elite). Punched cards had 80 columns.

"High-speed" printers (heck, some of them could do several pages
per minute) had 132 columns. The IBM printer at our university in
1966 had 132 hammers and a slidebar with about 50 glyphs . As the
correct glyph passed the hammer, it would strike. The sequence
was carefully scrambled to make the moments of impact more or
less random, so that printing a line would sound like somone
riffling a deck of cards. Of course, the students (which may or may
not have included me) figured out what that sequence was and
made the printer print it. The hammers did not quite strike at the
same instant, it took maybe 0.05 of a second, but printing a page
of those lines made the printer sound like a very loud metronome.
Alas, the slidebar tended to break during those pages :-(