Line Printers were these wonderful, old printers that could play music. They would hum away, some spitting pages out at the obscene rate of 50-75 pages a minute. The tractor feed printer paper would zoom through, sounding like a small jet engine. They would hum away, making scratching sounds as paper flew past the heads.
A chain with letters spins around a hammer. When the correct letter gets in front of the hammer, it fires, and the letter is printed on the page, as in a typewriter. The paper is then advanced a line. This is continued ad nauseam until the document is done. Because the chain would advance at different speeds, different pitches were created by the motor/drive system. moving from "A" to "1" would be higher pitched then moving from "A" to "C". This is because the hammer and type assembly would move across the page at a constant rate. The chain would have to move faster for some letter changes then others. The speed determined the note played. Thus printers could play music. The output for songs would look something like this:
AFAFAFAFAFAFAFAFAFAFAFAFAFAFAFAF
A1A1A1A1A1A1A1A1A1A1A1A1A1A1A1A1
W.W.W.W.W.W.W.W.W.W.W.W.W.W.W.W.W...etc.
By varying the letter patterns printed, notes could be created and sustained. Raindrops Keep Falling On My Head sound hilarious on the line printer. Engineers developed this in the 1960s. Some say they had to much free time on their hands, but I belive that they merely knew how to use technology to its fullest potential. The IBM 1403 printer can be heard at http://www.computerhistory.org/exhibits/highlights/.
Sources:
- line printer
- http://www.columbia.edu/acis/history/1403.html,
- http://www.computerhistory.org/exhibits/highlights/and
- other online sources
The comments I have gotten about this have been wonderful. Thanks to m turner, I think it was, for originally pointing this out to me.
CrAzE says re: Line Printer Music: oh lord
shyHyena says re Line Printer Music: I've heard of a similar thing being down with big honkin' electric motors, by varying the switching speed of the electronic speed controls... Any info on this would be appreciated, I am curious...