Atomic Awesome

Good Use of Government Resources

You may remember the SAGE network from such posts as Expand Your Radar Horizons (Parts 1 and Duex), and possibly some other I am forgetting regarding missile defense during the Cold War years. SAGE stands for Semi-Automatic Ground Environment, and essentially was a network of radar installations coupled with what passed for serious computing power at the time, creating a system that combined live radar input with pre-established flight information from commercial airliners that would give operators a live picture of the air traffic in the airspace of the US and Canada. Anything that was out of place could quickly be isolated and intercepted. At the heart of all this was of course the computer, the AN/FSQ-7 (2 computers per SAGE center, 21 such centers around the US), “the largest computer system ever built, each of the 24 installed machines[7]:9 weighed 250 tons and had two computers.[8] The AN/FSQ-7 used a total of 60,000 vacuum tubes[8] (49,000 in the computers)[7]:9 and up to 3 megawatts of electricity, performing about 75,000 instructions per second for networking regional radars.” (Wikipedia)

So what do you do with such a powerful computer system, which also happens to be the second ever real-time computer with an electronic graphical display? Why you use the situation display console, a 19-inch cathode ray tube (CRT) display (which drew vector-based lines or alphanumeric characters on any portion of the screen) to display a more, say, entertaining image!

All in the name of system testing, of course. See, the reason for 2 computers in each SAGE center was so that one would be running at all times, while the other would be down for maintenance. This required a means to seamlessly switch from one computer to the other. When the program was created in the late 1950s to check for proper system sync before the switch, someone decided the test image should be pleasing to the eye.

…the program that displayed the pin-up image was a diagnostic that tested data flow between the two SAGE computers on site (referred to as the A and B computers). At the end of every shift, as one computer was about to go offline and switch over to the other, the active machine would begin transferring flight and intercept data to the standby machine so there could be a seamless switch over.

Two switching consoles on site were used to handle this process. After running the diagnostic, if the pin-up displayed correctly on the screen, then data was being transferred between the A and B computers correctly. If the image displayed improperly, then the technicians immediately knew there was a problem.

When loaded, the pin-up image would be visible in flashing pulses that synchronized system-wide with the incoming flow of real-time radar data. (

The image in question appears to be based on a George Petty pin-up created for Esquire magazine in 1956, inserted into the test program by a nameless IBM technician. The only photo of the CRT display was taken by 21-year-old Airman First Class Lawrence A. Tipton in 1959. Technicians who worked in the SAGE centers recall seeing the image all the way up until 1983, when SAGE operation ended. All in all, not a bad run for some very early digital artwork.

Via and nerdcore.

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  • skitter

    The Soviets, of course, copied this in every detail, right down to pin-up.
    They didn't know why, but were sure it was important.

    • Vairship

      But since they work in metric instead of American Customary Units, their pixels came out a bit heavier…

  • CaptianNemo2001

    ""Which also happens to be the second ever real-time computer with an electronic graphical display?""
    So what was the first?

    ""The only photo of the CRT display was taken by 21-year-old Airman First Class Lawrence A. Tipton in 1959.""
    Likely because it was like "TOP SECRET". It is also not likely the only photo taken.