Date   : Tue, 11 Jun 2013 17:28:52 +0100
From   : adsb@... (Andrew Benham)
Subject: Acorn newline sequence

On 11/06/13 10:53, me@... wrote:
> On 11 Jun 2013,@00:39, Jules Richardson <jules.richardson99@...>
wrote:
> 
>> But in the TTY era I think it used to be CR first and then LF simply 
>> because returning the carriage took a relatively long time, and the 
>> hardware could be advancing the paper while the carriage was still in motion.
> 
> "The separation of the two functions concealed the fact that the print 
head could not return from the far right to the beginning of the next line 
in one-character time. That is why the sequence was always sent with the 
CR first. In fact, it was often necessary to send extra characters (extraneous 
CRs or NULs, which are ignored) to give the print head time to move to the
left margin. Even many early video displays required multiple character times
to scroll the display."
> 
> http://en.wikipedia.org/wiki/Newline#History

With old mechanical teleprinters using 5-bit code it was customary to
start a new line with <Carriage_Return><Carriage_Return><Line_Feed>
<Letter_Shift><Letter_Shift> in order to give the carriage enough time
to get to the start of the line and stop any bounce there might be.

In Unix-land, "man termcap" still shows options for adding delays after
some carriage-moving operations:

       dB   Delay in milliseconds for backspace on hardcopy terminals
       dC   Delay in milliseconds for carriage return on hardcopy
            terminals
       dF   Delay in milliseconds for form feed on hardcopy terminals
       dN   Delay in milliseconds for new line on hardcopy terminals
       dT   Delay in milliseconds for tabulator stop on hardcopy
            terminals
       dV   Delay in milliseconds for vertical tabulator stop on
            hardcopy terminals

-- 
Andrew Benham     Southgate, London N14, United Kingdom

The gates in my computer are AND OR and NOT, not "Bill"