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The width of 132 characters was the width of the line printers, which were the main output device of the first commercial electronic computers. The line printe
by adrian_b 2y ago
The width of 132 characters was the width of the line printers, which were the main output device of the first commercial electronic computers.
The line printers had been designed from the beginning as computer peripherals, because previously there was no need for such high printing speeds. They were called line printers because all 132 characters of a line were printed simultaneously, by impact.
The first computers were not multitasking, so they could not be used for anything else while printing. Because of this, a very high printing speed was necessary, which required the development of the line printers. Later, when printing no longer blocked the execution of other tasks, the very expensive line printers could be replaced in many cases by cheaper printers, like dot-matrix printers or daisy-wheel printers.
Many more recent operating systems, like Unix or MS-DOS, have kept the abbreviation LPT for printers, even if by that time the line printers were already obsolete and they were very seldom encountered.
All early experimental computers used teletype machines for interactive communication with the computer. In the later commercial computers, teletypes continued to be used for the operator console, while the batch jobs of the non-privileged computer users would have had only the line printer or the card puncher as output peripherals.
If there have ever been any teletypes with an output width greater than 80 columns, they must have been very seldom used. At the standard typewriter pitch of 10 cpi, 132 characters require paper with the width of 14 inches (including the perforated margins). That would have required a huge teletype. I do not believe that such a big teletype has existed.
- zabzonk 2y ago> do not believe that such a big teletype has existed. Decwriter II, according to wkipedia - https://en.wikipedia.org/wiki/DECwriter https://en.wikipedia.org/wiki/DECwriter. I've actually used one of these, but I can't remember the printing width.
- adrian_b 2y agoThanks for the link. Nevertheless, I see that Decwriter II was not a true teletype. It was a teletype emulator derived from a dot-matrix printer and it was introduced very late in the evolution of computers, in 1974, at a time when the true teletypes had already become obsolete and more than two decades after the line printers that have established the standard width of 132 characters. Decwriter II could provide a width of 132 characters only because the dot-matrix printer on which it was based was built to be able to use the standard line printer continuous perforated paper of 14 inches, like most other dot-matrix printers. It is likely that Decwriter II has been used much more often as a remote teleprinter than as an interactive teletype and in the latter case it was used only because some users were forced to use it because their bosses did not buy decent computer terminals for them.
- jonjacky 2y agoThose wide DECwriters were the standard console terminals for DEC systems in the late 1970s and early 1980s. It is the only kind of terminal shown on the cover and interior of DEC's VAX-11/780 Hardware Handbook [1] (especially see Preface p. x) We had two of these, for our VAX 11/780 (delivered 1980) and PDP 11/23 (1981). You wanted a printed record of everything that happened at the console. A system crash would print a register dump and other information that would scroll out of sight on a video terminal (there were no scrollback buffers then). 1. https://course.ece.cmu.edu/~ece447/s15/lib/exe/fetch.php?media=vax_hwhbk_1979.pdf https://course.ece.cmu.edu/~ece447/s15/lib/exe/fetch.php?med...
- flyinghamster 2y agoTeletype Model 38 (essentially a wide version of the 33 with a two-color ribbon) could print 132 columns as well.
- adrian_b 2y agoThat is interesting, but Model 38 was also a very late model (1972), launched at a time when teletypes were becoming obsolete and more than two decades after the line printers that have established the 132-character width. The existence of such very late wide teletypes did not have any influence on the appearance of the 132-character width, which had been used in line printers since around 1950.
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- hinkley 2y agoI did a lot of paper crafts with that wide format paper that one of my parents brought home from work pre-recycling. There was a certain thing I liked to make where the aspect ratio of the sheets was just perfect. That paper had neat green and white stripes on it too.
- Animats 2y ago> All early experimental computers used teletype machines for interactive communication with the computer. Some people liked Flexowriters instead of Teletypes. Flexowriters had upper and lower case characters, and a 6 bit code instead of 5 bits. Here's an LGP-30, from 1956, the first desk-sized "personal computer"[1] Vacuum tubes, drum memory, chrome bezel. Very 1950s. [1] https://www.youtube.com/watch?v=7WaYYNUCWMY https://www.youtube.com/watch?v=7WaYYNUCWMY