hancock4@[EMAIL PROTECTED]
wrote:
>On Mar 7, 4:55 pm, "Adam H. Kerman" <a...@[EMAIL PROTECTED]
> wrote:
>>I guess the question I should have asked was if those two obscure
>>characters were in use in computer languages in the mid 1950's.
>They may have been for future use, or mathematical notations.
>ASCII came out in 1962.
There were developments beginning in the mid 1950's. The standards
committee was formed in 1960. The big deal was convincing AT&T to
join, and thus did not promulgate a 6-bit code, and then promoting
its use internationally.
IBM promoted the idea of standardization, then couldn't produce
peripherals that could use ASCII in time for the release of System/360.
Instead, this used 8-bit EBCIDIC, a superset of the 6-bit code used on
1950's-era punchcards.
What I read is that the pizza and beer didn't run out for two years
because all the major cor****ations took parochial attitudes, but
finally, IBM and Teletype agreed on something resembling IBM's original
proposal, which broke the logjam.
For the first time, ASCII putting the codes into a reasonable order
to simplify sequencing, except that number came before letters. At the
time, numbers were sequenced after letters but that's no longer today's
practice.
>There's a Western Union Technical Bulletin available on the web with an
>article about it if anyone is interested. As an aside, WU wasn't
thrilled
>about it, it was quite happy with its 5-bit Baudot*.
Heh. Lack of lower case letters and punctuation and control characters
didn't make users all that thrilled with it, I suppose. The original
ASCII, as a political compromise, was designed for expansion and left
room for more control characters and lower case but didn't start with
them.
>About that time Teletype Corp came out with the model 33 ASR which
>used it. But I think most business communications, via WU Telex or
>AT&T TWX stayed with Baudot until the end.
From what I read, Teletype implemented ASCII immediately, so I don't think
that's correct.
>To this day I believe deaf TTY communications use Baudot.
In this country, yes. TDDs' development rather stagnated and became
isolated from communications device development. Still use accoustic
couplers, still use Baudot, weren't compatible with modems, etc.
This article http://wps.com/projects/codes/
comments that Baudot's
actual code was for a device with five "piano keys" that encoded a wire.
The code was modified by Murray. Western Union purchased the American
rights to Murray's code, then modified it further. It was then adapted
by CCITT which promulgated ITA2. It's ITA2 that is commonly called
"Baudot code" historically. There's a note that no actual teleprinter
built based on Baudot's actual code, which I didn't know. Murray was the
last individual to contribute code. Thereafter, adaptations and
modifications were done laboriously with consultations among
international committees.
>There was mention of a "backspace".
Decimal 008 was its control character. In the initial ASCII, the
eventual position used by backspace was held by Format Effector 0; it's
not known what FE0 did.
In a paper tape punch machine, BS would position the punch over the most
recently punched character. It would then be followed by DEL (which
punches all holes! 1111111) to obliterate the mistrake. So mistakes were
corrected by a two-code sequence in a paper tape medium.
In later revisions of ASCII, the dual-function punctuation and
diacritical mark characters came into being, using backspace to "build
up" characters in other Latin-based alphabets, but it didn't accomodate
sequencing.
>I don't recall Teletype machines having a backspace capability. If you
>wanted to overtype, you had to - return- to the beginning of a line
>(no linefeed), then space out as desired.
>The designers of ASCII included many things, such as lower case, which
>would not be needed for many years.
Not according to the article I just read comparing the original ASCII
with its later expansion. It appears that there'd be no consensus for
including lowercase till the next code revision, but they left a logical
place for it.
>I miss the functionality of cntl-G, the bell. On my PC, if I write a
>simple program to issue that, it will beep, but nowhere else.
Hm. You want a bell on your laser printer?
I love his comment on BEL: Out of band signalling
He also explains another control character I've always been curious
about, VT veritical tab. This was used by a business to fill in a form
remotely. Data was sent, with a VT to move the paper to the next vertical
tab. How was this controlled? With a special paper tape loop called a
Vertical Forms Unit! One would punch holes corresponding to the next
position you need the paper to be in to fill in the next field on the
form.
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