Got DR. CHALLENGER working last night! First on the phone in an app that emulates Commodore BASIC from the late 70’s, then online, in an Apple II BASIC emulator. (There is a description of DR. CHALLENGER and the 1978 computer it was written on in my article about AI here).
The online version was very helpful in debugging the program and finding syntax errors that arose from the OCR (Optical Character Recognition – How I got the old text printout into the new computer, without entering it by hand).
The other night, after another session of searching high and low on my computer hard drives and the house, I ran across a thin file folder tucked away behind some other files in a file box. It just said “COMPUTER SCI”, and in it were two stapled-together printouts of the program. Years ago I had laboriously transcribed DR. CHALLENGER line by line, by loading it into the old Ohio Scientific (OSI) Challenger 1P computer from a cassette tape, then showing sections of it (the display technology of the C1P could only show 25-by-25 characters on screen at a time) and typing them into another computer. It was then printed onto typewriter paper with a daisywheel printer, probably at my brothers office in the 80s (IBM PC days).
It now resides in a file on my Mac in Sublime Text 2, the text editor that programmers use these days.
Amazing to be running this ancient program on modern tools, and fun to be editing and debugging it with such convenience, and cross platform. Running Dr. on my phone is just crazy: I never would have imagined I’d be doing that, almost 40 years later (2018 – 1979 = 39).
The reason these interpreters will run my program is that they are both emulators of the same 6502-based BASIC, which is a BASIC interpreter written by Microsoft – Bill Gates and his friend Paul Allen did it themselves. In fact this is the earliest known software written by Microsoft, and has some funny sayings and comments, interesting historical comments, and sneaky Easter eggs in the code that Bill gates put in there to try and catch anyone claiming it was their own product.
This BASIC was used in several of the very first personal computers, including the Commodore Pet (where I saw the ELIZA program running that inspired the creation of DR. CHALLENGER), the Apple II, and the Ohio Scientific (OSI) models (the computer I had).