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  • APL PLOT element

    From Quadibloc@jsavard@ecn.ab.ca to comp.lang.apl on Sat Apr 10 08:19:42 2021
    From Newsgroup: comp.lang.apl

    On a Facebook group about Selectric typewriter repair, someone was
    showing off a set of Selectric elements he acquired. One of them was an
    APL PLOT element from IBM.
    I tried looking up information about it online. Even using Google Books, though, virtually no results turned up.
    I did find some snippet results which hint that it had the following characteristics:
    The resolution was 1/30 of an inch in both directions. This would require, as the 2741 used as a terminal was 10 pitch, fifteen copies of each plotting symbol on the element, in three possible positions across (1/3 of 1/10 is
    1/30) and five possible positions down (1/5 of 1/6 is 1/30).
    There were five different plotting symbols. As there are 88 characters on an element, and this would take up 75 positions, this would allow the ten digits from 0 to 9, and a minus sign, to be on the element as well, plus a horizontal rule and a vertical rule. (But this result was fragmentary, and could have
    been talking about something else like a daisywheel for all I know for sure.) I've seen a mention of a workspace 10 FINEPLOT. Since the element was
    from IBM with its name printed on the cap, I would tend to think that some means of using it was provided by IBM, but other references seem to
    associate this with Sharp APL.
    So if anyone has some information on this, please let me know.

    John Savard
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  • From Curtis Jones@curtis_jones@ieee.org to comp.lang.apl on Wed Apr 14 15:06:57 2021
    From Newsgroup: comp.lang.apl

    John,
    The fine-plot type ball and the workspace 20 PLOT (It was in Library 20 in San Jose) was one of the great attractions of APL to me. The plotting ball that we had in 1974 had dots and also short line segments that could be used to construct boxes. There was even a workspace that produced fairly attractive big letters. It may have been in 1975 that managers in IBM were asked to contribute money for a new fine-plot ball that had dots, circles and squares so several types of lines could be plotted. I managed to keep a magnetic-tape Selectric that had been modified to emulate an IBM 2741 terminal around until Graphpak in APL for the IBM PC Version 2 was adequate for my work. I'm really sorry to say that I don't know where to find any technical specs for those fine-plot "Selectric type elements". Curtis
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  • From Quadibloc@jsavard@ecn.ab.ca to comp.lang.apl on Wed Apr 14 20:18:55 2021
    From Newsgroup: comp.lang.apl

    On Wednesday, April 14, 2021 at 4:06:58 PM UTC-6, curtis...@ieee.org wrote:
    I'm really sorry to say that I don't know where to find any technical specs for those fine-plot "Selectric type elements".

    I have good news. The individual who acquired such an element, from whom I learned
    of its existence, was kind enough to type out a specimen.
    From that specimen, I was able to work out the details of the element, and I've shared
    my results with the world on this page: http://www.quadibloc.com/comp/aplint.htm
    just scroll down to the bottom.

    John Savard
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