[TUHS] Early Unix and Keyboard Skills

Paul Winalski paul.winalski at gmail.com
Fri Nov 4 01:17:38 AEST 2022

On 11/2/22, Ronald Natalie <ron at ronnatalie.com> wrote:
> I’m not sure the model 33 required a carriage return delay.   At 110
> baud it had plenty of time to move the carriage. back.
> Other printers (especially faster ones) weren’t so lucky, but the LA36
> decwriter had a catchup mode to print the backlog after a return.
> The LA120 was boustrophedonic so returns weren’t as much of an issue.

The model 33 had a very fast and powerful carriage return mechanism,
good for cracking walnuts, but it took up to two character times to
complete a CR.  If you didn't send two non-printing characters (such
as NUL), you risked having your character struck somewhere in the
middle of the line.

The LA36 DECwriter had a rather slow carriage return.  It would buffer
characters while a return was in progress and then print the buffered
characters at 60 characters/second, slowing down to the normal 30 cps
when caught up.  There was a company that sold modified LA36
controller boards that were hacked so that the LA36 always thought it
was in catch-up mode and could thus be run at double speed, provided
that you inserted NUL padding after a CR.  But that greatly reduced
the longevity of the print mechanism.

-Paul W.

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