Fun Fact: In the days of printing terminals (e.g. Model 33 ASR Teletype), it was not uncommon to be connected to computers via half-duplex circuits. This meant that everything you typed on the keyboard was immediately printed, just like a typewriter. In a situation like this, how do you hide someone's login password, which is just going to be printed on the paper roll possibly just sitting there for everyone to see later. The answer was to black out the paper BEFORE the user entered their password, by typing a series of different characters repeatedly over the same area after the password prompt. The result was a blacked out area of ink as long as the (not very long) maximum passwords lengths. When the user then typed their password, it vanished into the existing ink blob. For terminals that couldn't carriage return without a line feed, this could be accomplished with rapid backspacing. So now you know.
@bertkoor You really wanna try tell me about Teletypes? I used to repair and modify those babies. The Teletype (speaking ASR 33 for example) was inherently a full duplex device -- there was no mechanical connection between the keyboard/encoder and the printer mechanism. HOWEVER, the circuits they were attached to were often half-duplex, meaning everything typed was immediately echoed back to the keyboard and there was no way to avoid printing passwords as they were typed (or to prevent echoing back of anything else that was typed, for that matter). That's why the "ink blot" method for obscuring passwords was frequently used on those circuits.
@lauren it's unfortunate that Linux getty no longer handles TERM=tty33 and stty xcase correctly so you can't login from an ASR-33. Maybe I should try a BSD.
@weaselx86 I've seen that one before. Gonna need a big parts order to Skokie.
@lauren Now that you mention it, I remember this .... but how do you remember arcane details from 50 years ago (maybe only 40 years)?
@PeterLudemann It's both a blessing and a curse.
@lauren
Teletypes were not typewriters.
Iirc before entering a password it switched off local echo mode.