Spacewar! for the PDP-1

Spacewar! for the PDP-1 is now officially the oldest video game I have ever played, thanks to it being brought back to life in an emulator over at the Internet Archive.

The great-grandfather app of many games, including the Space Wars arcade game from the 70s, the emulator simulates as much of the PDP-1 experience as possible, including blinky lights.

Spacewar! Loaded!

Spacewar! Loaded!

Of course, it is raw… and the gravity is brutal.  I am doing all I can just to not crash into the sun in the first 30 seconds.

Boom! yet again!

Boom! yet again!

But when you consider the time frame… this was done in 1962… it is nothing short of amazing and a pretty good glimpse into the future.  It even has something of an Easter Egg.

Another addition to the Internet Archive’s Historical Software Collection.

4 thoughts on “Spacewar! for the PDP-1

  1. Ranamar

    Orbits, man, orbits. Get into something halfway stable and *then* start shooting. (Just watch out if you drop a torpedo exactly on your back path… shooting yourself down is easier than you’d think.) I feel like when I played Spacewar on a restored PDP-1, though, crashing into the sun just teleported you to the corner.

    But yeah, basic orbital mechanics is a core skill for that game, and, the faster you figure that out, the longer you have to pwn everyone else before they do, too. ;)


  2. noland

    Going into orbit: The basic maneuver is the so-called “CBS-opening”. Both players would turn their ships orthogonally to an imaginary axis pointing from the ship to the central star and would fire their thrusters to enter a stable orbit. By this, the ships would leave trails with some resemblance to the CBS-logo, hence the name. See:

    BTW: The emulator at seems to be a bit slow (in Chrome). You might also try:


  3. noland

    Ok, here’s the ultimate description, from an oral-history interview with Steve Russell, the original author of Spacewar! (interviewed by Al Kossow, CHM):

    Kossow: Right, that’s the whole thing with gravity and doing the, what’s that called, where you whip around the sun? Does it have a name, where you whip around the sun and you shoot?

    Russell: The closest name is the “CBS maneuver” is what happens when two lazy experts fight each other, which is they both turn at right angles to the sun, and fire for 3.5 or 4 seconds, so they’re now in stable orbits, and they know it. And then they turn at each other and start trying to place torpedoes where they think the other one is going to be. And so the trails turn into an eye around the sun, and CBS used that as a logo, so it got called the “CBS maneuver”. One of the spaceships can go the other way around the sun, so that both ships meet on the same side of the sun. But that seems usually to have less chance of winning. Not much less, but somewhat less.

    Kossow: It’s better that you stay on opposite sides, then?

    Russell: Yes.


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