Timeline for Why was the return key symbol ↵ drawn differently from the motion of a CR-LF?
Current License: CC BY-SA 4.0
30 events
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| Apr 29 at 19:43 | comment | added | supercat | Some "glass teletype" designs couldn't efficiently accommodate a CR without LF, and many were limited to 16 lines or so. Having a glass CRT process a CR followed by any number of linefeeds by advancing to the next line, scrolling only a single line off the top of the display, would in many cases have been more useful than having it respond to linefeed codes. | |
| May 2, 2022 at 20:50 | comment | added | tchrist | Just like how the possessive of the mix is the mix’s, so too is the possessive form of Chromatix only ever Chromatix’s with an apostrophe plus s. You cannot just add an apostrophe the way you can with the answers you get from all those nasty, biting chroma ticks that pass along diseases like color blindness. :) | |
| S May 2, 2022 at 19:31 | history | edited | Raffzahn | CC BY-SA 4.0 |
Corrected the typo of "where" misspelled as "were", and applied several other minor copyedit tweaks to provide enough changes for submission of the spelling fix to be allowed
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| S May 2, 2022 at 19:31 | history | suggested | tchrist | CC BY-SA 4.0 |
Corrected the typo of "where" misspelled as "were", and applied several other minor copyedit tweaks to provide enough changes for submission of the spelling fix to be allowed
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| May 2, 2022 at 14:00 | review | Suggested edits | |||
| S May 2, 2022 at 19:31 | |||||
| Apr 19, 2022 at 20:21 | comment | added | Rowan Hawkins | @Raffzahn That is correct -- for the platen movement, which is my point. The HAND movement, using you left hand pushing the lever on the platen, is directly to the right. That has nothing to do with the symbol. Once typewriters went electric the CR was executed first since that took the most time and the LF happened some time during the return it was hard to see on a normal typewriter, but across 120 or more columns on a wide printer it happens someplace in the middle because the CR could take a more than a second. Where the LF is a fraction of a second. | |
| Apr 19, 2022 at 20:17 | comment | added | supercat | @Raffzahn: I think his point was that on most typewriters, a carriage return is accomplished by moving the carriage to its rightmost position (constrained by the margin tab), which will move the left side of the paper toward the place where the type bars strike. | |
| Apr 19, 2022 at 19:43 | comment | added | Raffzahn | @RowanHawkins Of course I do not know what typewriter you're using, but the one right next to me does, when operated, first turn the platen to advance to the next line (vertical movement). Only when the next line is reached, the horizontal movement of the whole carriage is performed. So down first (↵). | |
| Apr 19, 2022 at 19:11 | comment | added | Rowan Hawkins | This is incorrect... "symbol used quite closely follows the hand movement when issuing a new line." The hand movement on a manual typewriter is opposite the symbol. You are pushing the platen to the right to move the start position for the next character to the left. The character position translates across the platen similar to the symbol. Otherwise the platen would be fixed in space and a moving typewriter hanging from it would be really hard to use. I have put in an edit to correct this but I'm making sure its understood here if it doesn't go through. | |
| Apr 19, 2022 at 17:25 | review | Suggested edits | |||
| Apr 19, 2022 at 18:22 | |||||
| Apr 19, 2022 at 16:43 | history | edited | Toby Speight | CC BY-SA 4.0 |
Spelling and grammar
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| Mar 20, 2020 at 21:02 | comment | added | JdeBP | See unix.stackexchange.com/a/411830/5132 and comments for Multics defining LF as both carriage return and line feed for device independent terminal I/O. | |
| Mar 19, 2020 at 23:39 | comment | added | Raffzahn | @JanusBahsJacquet Sure, I'm aware of that, still looking at the symbol, it seams related, a small turtle crawling along below a text line ... don't you think so? Not, when I comes to French spelling (English as well) , I do firmly belive it's a topic to be spared until human kind has reached lasting world peace and mastered FTL travel. | |
| Mar 19, 2020 at 23:31 | comment | added | Janus Bahs Jacquet | @Raffzahn Just for the sake of completion, the turtle sense of French caret is unrelated to the Latin verb – it’s a borrowing from Spanish carey, which in itself is a Taíno word (from the Caribbean). The final t in caret is purely orthographic; they could just as well have spelt it caré or carai(e) instead. | |
| Mar 19, 2020 at 19:15 | history | edited | Raffzahn | CC BY-SA 4.0 |
added 1 character in body
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| Mar 19, 2020 at 19:15 | comment | added | Raffzahn | @DrSheldon Thanks. I wouldn't mind, as he was the first to point out the core issue. I just added bells & whistles. | |
| Mar 19, 2020 at 19:04 | comment | added | mongo | I spent several years writing drivers and diagnostics for disk and tape drives. Development usually started on a PDP-8. I wrote everything in assembler. A CR input would be mapped to a CR/LF, but it could be a LF/CR, the peripheral TTY did not care. The Teletypes were marked CR, but some IBM and CDC terminals marked keys as NL. On the Teletype, CR meant CR and LF meant LF, and a CR would be mapped to echo out a CR/LF combination. To overprint (bold) the characters would be printed, then a CR, then printed again. | |
| Mar 19, 2020 at 16:19 | vote | accept | DrSheldon | ||
| Mar 19, 2020 at 14:58 | comment | added | Raffzahn | @StephenKitt Yes. Implied CR was for one available on Flexowriters, but as well on mechanical TTY like the 1958 Siemens T100. After all, it's CR was done via a spring and all needed to add the functionality was an additional lever releasing that spring as well with LF. I still remember being trained to use it accordingly during service (at that time 1979 with the successor T1000 model). | |
| Mar 19, 2020 at 14:55 | comment | added | Raffzahn |
@CaptainMan LOL. No, but that's a cool way for a fake explanation. Caret is Latin and means 'he/she is missing (something)' (third person singular of careo). When editing/correcting a text (back before computers) an upward chevron was used (below the line) to mark where something had to be inserted - which is why a text cursor nowadays is called a caret, as it's were text gets inserted (when typing). In French it also has the meaning of turtle. < for CR is simply a symbol showing that the carriage will be moved to the left. Symbols save the effort to make country specific keycaps.
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| Mar 19, 2020 at 14:22 | comment | added | Captain Man |
I noticed you mention the "enter" used to say "CAR RET" and also mention some symbols used < for CR. Is that why ^ is called a "carret"?
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| Mar 19, 2020 at 14:10 | history | edited | Raffzahn | CC BY-SA 4.0 |
added 299 characters in body
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| Mar 19, 2020 at 14:05 | history | edited | Raffzahn | CC BY-SA 4.0 |
added 299 characters in body
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| Mar 19, 2020 at 13:47 | comment | added | Solomon Slow |
@Raffzahn, Yes The problem (application programs needed to be aware of control codes and timing requirements for a specific teleprinter) existed before the solution (UNIX translates \n into whatever sequence of CR and LF and NULs will make the teleprinter happy) was invented. I personally remember writing application code for some non-UNIX minicomputer (or maybe a micro, not sure), and having to find out the right number of NUL characters to send to prevent the first character of the next line from being struck while the print head still was in-flight back to the home position.
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| Mar 19, 2020 at 13:00 | comment | added | Stephen Kitt | Did CR-on-LF TTYs predate Multics (1964)? | |
| Mar 19, 2020 at 12:42 | comment | added | Raffzahn | @SolomonSlow The considerations predates the existence of 'line discipline'. During the 60s it was still common, that machines had no OS, or it was simply ignored - much like 20+ years later with PC-DOS programming. Also, note that 'decoupling' is just a way of saying 'simplifying' - isn't it? | |
| S Mar 19, 2020 at 12:02 | history | suggested | Toby Speight | CC BY-SA 4.0 |
Spelling and grammar
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| Mar 19, 2020 at 11:54 | review | Suggested edits | |||
| S Mar 19, 2020 at 12:02 | |||||
| Mar 19, 2020 at 11:42 | comment | added | Solomon Slow | Re, "simplyfication of text handling" The point wasn't just to make it simpler. The point was, to decouple the encoding of text in a file or, the text stream output by a program, from the requirements of any particular output device. Also note: It could be that the output device itself was configured to correctly interpret the LF character, or (more often than not, is my guess) the line discipline (a.k.a., "line driver") would convert the NL to an appropriate sequence of control characters and/or time delays. | |
| Mar 19, 2020 at 10:05 | history | answered | Raffzahn | CC BY-SA 4.0 |