Monday, June 17, 2024

55 year old bug fixed

This may be the oldest bug fix in history, in the 1969 "Lunar Lander" text based computer game.  I really enjoyed that, back in the 1970s.


And yes, it printed out on paper.  The story is very cool:

In 2009, just short of the 40th anniversary of the first Moon landing, I set out to find the author of the original Lunar Lander game, which was then primarily known as a graphical game, thanks to the graphical version from 1974 and a 1979 Atari arcade title. When I discovered that Storer created the oldest known version as a teletype game, I interviewed him and wrote up a history of the game. Storer later released the source code to the original game, written in FOCAL, on his website.

...

Fast forward to 2024, when Martin—an AI expert, game developer, and former postdoctoral associate at MIT—stumbled upon a bug in Storer's high school code while exploring what he believed was the optimal strategy for landing the module with maximum fuel efficiency—a technique known among Kerbal Space Program enthusiasts as the "suicide burn." This method involves falling freely to build up speed and then igniting the engines at the last possible moment to slow down just enough to touch down safely. He also tried another approach—a more gentle landing.

"I recently explored the optimal fuel burn schedule to land as gently as possible and with maximum remaining fuel," Martin wrote on his blog. "Surprisingly, the theoretical best strategy didn’t work. The game falsely thinks the lander doesn’t touch down on the surface when in fact it does. Digging in, I was amazed by the sophisticated physics and numerical computing in the game. Eventually I found a bug: a missing 'divide by two' that had seemingly gone unnoticed for nearly 55 years."

Very cool story.

8 comments:

  1. HMS Defiant, and I didn't even mention Wumpus!

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  2. I remember some early text based video games for which you had to read and think. It was a lot of fun. You could play as group and discuss what you that the answers were.

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  3. Was it a Mountain Wampus?
    Did I find a fellow MULE fan?

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  4. Now I feel old. I seem to remember this on a Tektronix terminal, graphical?

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  5. I played that game on a Teletype just like that back in the late '70s. I also played a version of it on a TI-57 programmable calculator in the mid '70s.

    It's amazing that bug didn't get discovered for so long, considering how many thousands of people have looked at that source code.

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  6. We used up reams and reams of paper at Hinds Junior College in 1978 or so playing those games. We were supposed to be taking practice English Tests but the games subfolder was much more interesting.


    K L I N G O N D E S T R O Y E D. . . .

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  7. That was a lunchtime game in h.s., with a punch tape program.
    The glitch explains why it was so hard: GIGO.

    The other go-to was "Hammurabi".
    De-bug that one next.

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