[GreenKeys] Why have local reverse line feed and local backspace?

[Jim Haynes]

That's always been a mystery to me too, and of course all the people who
would know about it are dead now.  Most of them anyway.

It kinda disgusts me to see those mod kits.  Somebody decided it was 
Really Important to have those features, which surely were not forseen in 
the original design.  So some engineer(s) had to figure out how to work 
around the parts that were already in there to put in these features and 
it was probably far from easy.  Then the tooling had to be made to produce 
the parts.  And I spoze by the time of Model 37 they had decided to plan 
ahead to put those feature in, which was easier than retrofit kits at 
least.

Once you have the local backspace and reverse line feed I guess it's not
that hard to have the stunt box convert those to online actions.  And
there they might be useful.

Especially in ASCII there was considered to be a need to backspace and
type over characters that had already been printed to get some of the
strange characters that are not in English.  Such as the squiggle over
N in Spanish, and the slashed O in Nordic languages.  And this all became
a mess with video terminals, because most of them use backspace in the
sense of backspace-and-erase.  Early on some of them could not do that
and you had to do backspace-space-backspace to erase a character.  Which
a hard copy terminal could not do anyhow.  So all the hard thinking and
arguing that the ASCII committees did was wasted on CRT terminals.

Model 37 as I recall had forward and reverse half line feed, for the 
purpose of printing subscripts and superscripts.  No doubt something that 
Bell Labs said was needed, while all the rest of the world had to make do 
on computers with Model 33s.  Trying to do mathematical typesetting on a 
teleprinter is just beyond reasonable.

Model 37 had online settable horizontal tabs.  I argued that was also
a bad idea.  If you're going to use the machine connected to a computer
you don't need to waste time with that mechanism, just have a character
that jumps horizontally and let the computer figure out how many jumps
and spaces are needed to get to the desired position.  And of course the
computer stuff we were using at the time like BASIC assumed tabs were
set 8 spaces apart and would be handled by spacing if the printer did
not have horizontal tab.

Pre-computer there were some ASR sets made for use with forms, where
a control tape would position the type box to the next position on
the form automatically.  Trying to do what was reasonable with a computer
when you didn't have a computer.

 	---

 	"Ya can argue all ya wanna, but it's dif'rent than it was."
 	"No it ain't! No it ain't!  But ya gotta know the territory."
 		Meredith Willson, The Music Man