Timeline for Why did Acorn use LF+CR instead of CR+LF as a line ending?
Current License: CC BY-SA 4.0
14 events
| when toggle format | what | by | license | comment | |
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| Apr 30 at 6:10 | comment | added | UncleBod | Does the specifications that teh Acorn BBC was made against still exist somewhere? It could be that BBC (the British Broadcasting Corparation) included LF/CR as a thing in their specs. | |
| Apr 29 at 22:26 | comment | added | Raffzahn | @dirkt Erm, no, some early printers DID care for it being CR LF. That's why some Unix printer drivers do insert fill characters before a CR if preceded by LF. That way user output could be either way without screwing output timing. | |
| Apr 29 at 22:01 | vote | accept | Simon Kissane | ||
| Apr 29 at 17:21 | comment | added | supercat | @paxdiablo: If the carriage was near the right edge, many teletypes would start advancing the paper in response to an LF command before the carriage had reached the left. It would have been trivial for teletypes to e.g. make bit both bit patterns of the form 000 101x advance the paper, and 000 10x1 reset the carriage (so 000 1011 would do both), but any code that reset the carriage would still need to be followed by a code that could be processed while the carriage was still resetting--a role which LF played quite nicely. | |
| Apr 29 at 13:00 | answer | added | TonyM | timeline score: 26 | |
| Apr 28 at 1:06 | comment | added | Jon Custer | Same reason the UK drives on the left??? | |
| Apr 27 at 23:43 | comment | added | paxdiablo |
LF+CR is actually what typewriters used to do. When using the lever to return the carriage to the left (which is, after all, where CR came from), the first action of the lever was to rotate the roller so that the paper "scrolled up". Then, continued pressure on the lever pushed the carriage to the left. So Acorn is the only one that got it right :-)
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| Apr 27 at 12:53 | comment | added | Lou Knee | IMO LF first is better otherwise the varied crud that has built up around the print head of the ubiquitous Epson DMP smears the freshly printed line. See also retrocomputing.stackexchange.com/questions/14169/… | |
| Apr 27 at 12:38 | comment | added | dave | @Frog - every teletype driver understood the need for fill characters. But that seems like a separate matter from line delimiters stored in files. | |
| Apr 27 at 8:31 | comment | added | Frog | @dirkt I found out the hard way that it does matter for some printers - I had a 110 baud teletype; a CR would send the carriage back left but it would take a little time and the LF would take up enough time for the action to complete. LF/CR would appear to work but the first character of the next line would get printed while the carriage was still in motion. | |
| Apr 27 at 8:24 | comment | added | mmmmmm | I assume by Acorn BBC they mean BBC Micro and Electron from the reference used - other 8 bit machines like Atom and the earlier hardware aren't covered by that documentation. | |
| Apr 27 at 7:04 | comment | added | tofro | @dirkt Actually, it's not only printers that wouldn't care - most terminals as well. So, maybe the answer is "because it didn't matter"? | |
| Apr 27 at 6:20 | comment | added | dirkt | Maybe the important part is "spooled output": It's supposed to go to a printer, and early printers don't really care if you do CR LF or LF CR. So it looks like it's less a general line-ending convention (that seems to be just CR for Acorn), but more of a conversion. | |
| Apr 27 at 5:55 | history | asked | Simon Kissane | CC BY-SA 4.0 |