Lunar lander first good run

[@marcramsey7196]

I am curious about the origin of the game you have. Can you control the attitude of the LEM to adjust the angle of thrust? I ask as I wrote a very similar paper tape-based BASIC lunar landing program in high school in 1970, running on timeshared PDP-8. At the time I taught myself enough calculus (with help from my then physics teacher) to come up with reasonably accurate orbital dynamics. The LEM would remain in orbit unless adequate retro-thrust was provided, and you could run out of fuel and be marooned in orbit rather than crashing. The program you have either inspired mine, or mine inspired theirs, they look too similar to be coincidental. I believe I submitted the program to DECUS (the DEC user group), so it would have been in the public domain by 1972, if that's when SEL started distributing it. FWIW, I lasted one year in college, then dropped out and started writing code professionally. Never worked with an SEL-810, but did spend many years writing assembler code for barebones PDP-8s, 11s, and DG Novas.

[@happycomputerguy]

The software came from a company called Wallace Ohran and Sons. There is no concept of retro thrust, or angle of thrust. It was distributed as a demo of their basic compiler

[@marcramsey7196]

Trivia: Wallace Ohran and Sons still exists (as a real estate firm), I suspect the compiler was written by son Richard, who was a CS grad student at University of Utah and later worked with Niklaus Wirth (of Pascal fame) developing the Modula compiler. The final version of the software I wrote was more complicated to play, I was the only one amongst my friends who could actually land it, and it took 20 or 30 minutes to do so. We had no display terminals, just ASR33 teletypes, so we also wasted a lot of paper. I originally wrote a simplified vertical-only version, but I don't remember if that also was submitted to DECUS. Is the crater Clavius mentioned if you land successfully? That was the intended target in my code (inspired by the movie 2001). Otherwise, it looks very much like I remember it. Thanks, the later video showing the boot up process is fun, it showed my daughter (who is a year out of Stanford with a CS degree) what it was like to boot a computer when I was her age, plus there is a chance she saw some of my old code running.

[@marcramsey7196]

I'm going to debunk my own claim, this article suggests the version you have is closest to one originally written in 1969 by a student at a high school a few miles away from mine: web.archive.org/web/20160116075236/www.technologizer.com/2009/07/19/lunar-lander/ I must have seen it a few months later, decided it was a bit lame because it only handled vertical descent, and wrote my own version that actually simulated lunar orbit.

[@happycomputerguy]

Awesome! This is all very interesting, I wonder if there is any chance Richard Ohlan would have a copy of his full compiler.