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8

It's important to keep in mind, that there weren't that much symbols using overstrike in basic (IBM) APL. By using an 8 bit codeset they all could be integrated. The most common charset on the mainframe side was Page 293 which extends EBCDIC with all (at that time) legal APL codes. With APL2 code handling became more complicated and Page 293 was replaced by ...


5

IBM had several different APL mainframe implementations, and they where updated and modified over many years to support different types of hardware and I/O equipment over their life time. The source for one of the earliest APL implementations for System/360 is available from the Computer History Museum. As far as I can remember they assign unique codes to ...


5

Some 3270 terminals supported an optional Programmed Symbols feature, allowing the use of arbitrary character bitmaps. This was available on the 3279 Color Display Station (models 2B and 3B), the 3278 Display Station (models 2, 3 and 4) and the 3270 PC (with the Programmed Symbols card).


4

I realize that it's been over a year, but thanks to all for responding. The terminal in question WAS a 3179G. I had figured it must have been because it had the graphics ability to render the APL2 characters (the standard APL characters were part of text mode on most of the terminals at that time). However, it turns out the 3179G did have the APL2 ...


4

I was once writing an APL compiler (never finished, having figured I could single-handedly write a compiler in a 10 week undergraduate programming project), and the choice I made was to have an internal 8-bit character set where each composite symbol was a single character. This seemed an obvious choice to me, since that way you're separated from how that ...


3

It's important to keep in mind, that there weren't that much symbols using overstrike in basic (IBM) APL. By using an 8 bit codeset they all could be integrated. The most common charset was Page 293 which extends EBCDIC with all legal APL codes. Symbols that get generated per overstrike, like log (⍟ which is 'Power-Overstrike' or PO), got their own code ...


1

1985, it could have easily been any IBM PC equipped with a Hercules Monochrome Graphics card. More likely, however (as you said this was on IBM premises), the machines capable of displaying the full APL character set were XT-370, mixed-mode beasts consisting of a PC/XT, a terminal emulator and dual-Motorola 68000 for the emulation.


1

This is a late answer but I hope that it might to some small extent be useful. I've not delved into the original IBM APL to any extent other than to adapt my 2741 emulator to handle it, but have gone moderately deeply into other applications in particular derivatives of Ken Thompson's APL/11. I can't remember whether the source of IBM APL was ever made ...


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