[GreenKeys] Original meaning of ASCII codes

[Douglas W. Jones]

On Sunday, November 17, 2002, at 09:51 AM, jhaynes@alumni.uark.edu wrote:

> Then the article
> doesn't make a clear distinction between 1961 ASCII and 1968 ASCII.

Of course I didn't make a clear distinction, because nobody but the
ASCII purists ever did.  ASR 33 teletypes built to 1961 standards
remained in use into the mid 1970's, and while we knew, when we
developed our software, that there were changes to the standard
like lower case and replacement of up-arrow with caret, we
developed our applications to the defacto standard established by
our hardware.

So, Pascal, a programming language developed around 1968, used the
up-arrow as a pointer symbol, because it was an arrow that pointed
any way but left (left arrow would have been used for assignment).
As terminals arrived that used caret, we wrote filter software to
overprint caret with vertical bar to make it print as up arrow.
Then came "glass teletypes" without overprinting, and we swallowed
our pride and began to accept the change to caret as permanent.

(The GE Terminet line of impact printers were wonderful things,
not only did they operate at up to 1200 baud, but they came with
extra print fingers in unused print positions on the print band.
With a pair of pliers, you could pull fingers from the band and
rearrange them, so you could make your Terminet print classic ASCII
or new ASCII.)

					Doug Jones
					jones@cs.uiowa.edu