shebang strange thing...

Steve Holden sholden at holdenweb.com
Fri Jun 27 03:21:20 CEST 2003


"Ben Finney" <bignose-hates-spam at and-zip-does-too.com.au> wrote in message
news:slrnbfn2eb.rbb.bignose-hates-spam at iris.polar.local...
> On 26 Jun 2003 12:25:55 -0700, - wrote:
> > I think the terminology is not taken from typewriters, but from some
> > old printers where you needed both characters to start a new line.
> >
> > CR moved the print head to the beginning of the line
>
> CR stands for "carriage return".  If you're talking about a print head
> moving across the paper, you're no longer talking about a carriage
> "returning", so the terminology obviously didn't come from electric
> printers.
>
> Carriage Return is a direct reference to the paper carriage on a manual
> typewriter.  These predate electric printing machines, and thus the
> terminology was borrowed when teletypes needed control codes to control
> their print head.
>
> On such typewriters, the "line feed" function was also separate; once
> the carriage was returned to the start of the line, one could cause
> the paper to feed up a line at a time to introduce more vertical space;
> this didn't affect the position of the paper carriage, so was
> conceptually a separate operation.
>
> So, it was teletypes that needlessly preserved the CR and LF as separate
> control operations, due to the typewriter-based thinking of their
> designers.  If they'd been combined into the one operation, we would
> have all the same functionality but none of the confusion over line
> ending controls.
>

Although in actual fact the KSR33 teletype did need a fifth of a second to
guarantee that the print head would have returned to the left margin from
column 72 haracters was a "feature". Sometimes you would (all right, *I*
would) depress the two keys in the wrong order, and the result was that you
would see a single character printed in the middle of the new line during
the "flyback" period.

mobile-mine-of-useless-information-ly y'rs  - steve
--
Steve Holden                                  http://www.holdenweb.com/
Python Web Programming                 http://pydish.holdenweb.com/pwp/







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