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posted by
martyb
on Sunday October 07 2018, @01:14PM
from the have-you-ever-programmed-a-6502? dept.
from the have-you-ever-programmed-a-6502? dept.
Adafruit visited the history of the LOGO "turtle graphics" language not long ago.
Now on Twitter, folks have found the source code for the LOGO program used on Apple II computers. Source on GitHub.
It turns out that the program was written on a DEC PDP-10 minicomputer running the Incompatible Timesharing System (ITS).
I'd take it that the code is in 6502 assembly and the program works the whole Apple II memory map for functionality. Did ITS have a 6502 cross-compiler or did the MIDAS program have separate target environments?
Very interesting programming archaeology – see the source code yourself along with the full PDP-10 ITS image still maintained today.
-- submitted from IRC
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The Apple II Source Code for the LOGO Language Found
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Fascinating is a word I use for the unexpected.
-- Spock, "The Squire of Gothos", stardate 2124.5
(Score: 2) by Rich on Monday October 08 2018, @01:56PM (3 children)
Mine had two switches soldered in, a toggle to disable the software switching of the card (so the interrupt vectors were immutable), and a pushbutton for NMI. Hello "Snapshot"! Those were the days. :) Eventually I got a Saturn 128K card, but my mind is blurry whether i used to swap those two (which would have been extra effort, because the classic language card tapped into one of the 4116 sockets, and I don't remember this particular socket wearing out).
I wrote all the embedded code for a Woz machine clone in a standalone RS-232 connected "smart" floppy drive that was solely made to read machine knitting-patterns (which apparently was a total Apple II domain) into newer Silicon Graphics workstations. I guess that's why these particular details stuck so well (besides helping out the occasional game with a ..er.. compatibility-improved RWTS...). A friend then did the DOS3.3 file system utilities for the DOS and Unix machines.
Recently, I also started wearing a long grey beard.
(Score: 2) by bzipitidoo on Monday October 08 2018, @06:18PM (2 children)
Cool. I didn't have that hardware mod, but I did have a toggle switch to set the floppy disk write protection any way I wanted (on, off, or detect the notch), and a rotary pot from an old radio to control the volume. Saved a lot of bother punching notches for the reverse sides of floppies. I also used, as I recall, a 130 ohm resistor to touch 2 pins in any expansion slot-- maybe it was pin 29 and 32-- and this generated an interrupt, breaking into any BASIC program. Never got around to wiring that resistor in, in a more permanent way, with a push button momentary switch.
I also have a few gray hairs in my beard :p.
(Score: 2) by Rich on Monday October 08 2018, @07:17PM
If you ever get to central Germany and want to discuss further details (and lament how the world's come down since), the beer's on me. ;)
(Score: 0) by Anonymous Coward on Monday October 08 2018, @07:26PM
Beard was, seemingly, mandatory if you worked at computer shops that sold Apple computers (although they typically also sold kaypro and other garbage game machines). The new-fangled hipsters has not a clue.