Post by @fanf@mendeddrum.org

2026-07-29 15:00 UTC

on a teletype (or similar printing mechanism) if you are printing a like with lots of overstrike (eg an underlined heading) is it faster to print the line, carriage return, print the overstrike; or to use short backspace-overstrike sequences? i’m wondering how useful CR was apart from a CRLF sequence

Replies (3)

@fanf@mendeddrum.org 2026-07-29 15:44

i guess i could have thought of the old unix crdelay feature which only went up to 3, which suggests how much slower cr was than bs (but i still wonder how much the speed was determined by serial baud rate and how much by mechanical limits) https://man.freebsd.org/cgi/man.cgi?query=stty&apropos=0&sektion=1&manpath=Unix+Seventh+Edition&format=html

Open ##4206568
@resuna@ohai.social 2026-07-29 15:03

@fanf@mendeddrum.org Back in the day I wrote a program to optimize printing of text files containing such shenanigans, and what I ended up doing was reading the whole line, outputting *just* the overstrikes, sending a carriage return, and outputting the letters. * It was WAY faster, especially on a device with an actual carriage that moved and had inertia. * If you were displaying on a device that didn't handle overstrikes (like a CRT) the result was still readable.

Open ##5101518
@mjd@mathstodon.xyz 2026-07-29 15:04

@fanf@mendeddrum.org Teletypes didn't have backspace. That's why the Unix TTY driver had (has?) a setting that makes it echo a backslash and then a copy of the deleted character.

Open ##5101526