Slashed letter O, unslashed letter zero
Paul Koning
paulkoning at comcast.net
Tue Apr 26 16:14:30 CDT 2022
> On Apr 26, 2022, at 4:41 PM, ben via cctalk <cctalk at classiccmp.org> wrote:
>
> ...
> PS: Did any common I/O devices have the ALGOL symbols Less than or Equals, Greater than or equals , not , arrows and other misc symbols?
Yes, the Flexowriters at TU Eindhoven used to punch ALGOL programs for the Electrologica X8 machine there (late 1960s through early 1970s). As I recall, Dijkstra made some comment somewhere about the usefulness of being able to specify your own character set.
Those machines had upper/lower case letters, several special character such as the logic symbols not, or, and, the subscript 10 for exponential notation numbers, plus non-escaping underline and vertical bar. The underline was used for keywords, so the ALGOL keyword "begin" was keyed as _b_e_g_i_n. It would also make several other special characters, for example _= (underlined equal) is the Boolean equivalence operator, and _ followed by the not symbol gives you the "implies" operator, and _< is less-or-equal. The vertical bar would also make several overstruck symbols, for example |= becomes not-equal, | followed by the and symbol is uparrow (for exponentiation). The local inventions |< and |> were used for string quotes.
Here's a sample of what it would look like printed on the Flexowriter. The line printers were upper-case only; they'd print lower case letters as upper case, upper case letters overprinted with a period. Ugh...
paul
More information about the cctech
mailing list