Re: Binary or Ascii Text?
- From: "Herbert Rosenau" <os2guy@xxxxxxxxxxxxx>
- Date: Sun, 9 Apr 2006 19:01:03 +0000 (UTC)
On Sat, 1 Apr 2006 16:00:58 UTC, "osmium" <r124c4u102@xxxxxxxxxxx>
wrote:
"P.J. Plauger" writes:
So it was a concession to ASCII.
Not really.
I realized that back space might enter into that too, but thought there
might have been problems with that considering the physical nature of actual
drum printers, chain printers and so on.
So are you saying that the initial release of the ASCII standard said that
LF was to do line feed AND carriage return? What was the point then, of
having them as separate codes? Unfortunately I don't have the text that
goes with my pre-historic ASCII chart, only a single page showing the
glyphs.
In late 60th and early 70the there was no device available today known
as screen. Tere were line printers, punch card and paper reader and
writers, and TTY devices combining keyboard, puch paper reader and
writer and a character printer. That printer was able to use singe
control chars like
- cr - caridge return - point print unit back to column 1
- lf - linefeed - feed paper to next line
- ff - formfeed - feed paper to next page stop on
the control ribbon
- backspace - one fixed character position back on same
line
- backline - page one line back
Some of these devices werde dumb enogh to get the next character
printed even before the device was able to reach character position 1.
So to get a clean printout you had to do cr before lf to hold the
device until lf was done.
Anyway to get a new line you must give out lf or the prit head would
put the char on the position it was at the time it got the order to
print it.
On mainframes the TTY used was mainly configured to make a cr even
when it got an lf to optimise the programs and save one character in
text (memory was bare and expensive even as the was able to
multitask). The upcoming microprocessors (mostenly homebrowed by
highly different manufacturers were limited in multitasking on the
different hardware levels (mostenly 16) the CPU was able to control
and designed more primitive. They required even more dumb TTY or more
intelligent customer builded I/O devices.
At the time C was created there was a typica computer either a
mainframe with
- a lot of punch card readers as program input
- a lot of magnetic tape devises as data store
- 1 or more punch card writer(s)
- some paper tape readers and writers
- one or more line printers (the first music devices :-)
for developers)
- later then a high number of removeable hard disk
- 1 TTY as operator console
No wouder that the C runtime is not created to handle user input well
but ideal for handling computer designed input like punch cards.
The upcoming microprocessors were designed to control mashines, having
only
- special devices to control mashines
- paper tape punchers and readers
- magnetic tape writers
- seldom line printers
- TTY as operator console.
Ages later they got moved into bureaus and other kinds of special
devices and TTY like devices as user input/output devices.
Modern GUIs are properitary anyway and does not use the C runtime for
user oriented I/O anyway.
--
Tschau/Bye
Herbert
Visit http://www.ecomstation.de the home of german eComStation
eComStation 1.2 Deutsch ist da!
.
- References:
- Re: Binary or Ascii Text?
- From: Me
- Re: Binary or Ascii Text?
- From: Joe Wright
- Re: Binary or Ascii Text?
- From: P.J. Plauger
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