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ICBMs and the first mass-produced ‘micro’ computers

by Charlie Vono of bread, was about a half cubic foot in volume, and weighed in at
special to Aerotech News about 26 pounds. This was “micro” in the 1970s. It had a capacity
of around 7,000 11 or 24-bit words.
Because fighting the Cold War involved focused dedication, Why was the D-37C the first mass produced small computer?
secrets and emerging technology, much history is unknown to the There’s a book here on my bookshelf to answer that question. If
general public. the history of placing computers in missiles and aircraft interests
They often are not aware enough of the tech history of the Cold you, you can still get an old copy on Amazon for around $40. See
War to even wonder about it. Yet the technology of our world figure 3 caption for details. Turning to page 93…
today was profoundly shaped by this war. And perhaps there are “… a change in requirements … made demands … that discrete
even a few lessons to be learned. That is, old Cold War solutions, circuits could not meet … a change in the U.S. strategic policy from
and how they might apply to today’s problems. massive retaliation to a flexible response. This meant a need to retar-
Here is an example of something that many already know and Figure 1: Photo thanks to Nathan Zeldes, CC BY-SA 4.0 get and thus reprogram the missile up to the instant before launch.”
more should: We owe our speed in getting personal computers to creativecommons, via Wikimedia Commons
Cold War nuclear tipped rockets. much like FORTRAN … called ALGOL … using card decks. See
It was just an engineer’s dream for years. What if we could actu- By Paul E. Ceruzzi, MIT
ally fit a digital computer into an aircraft or a missile? figure 2 for an example card from a computer card deck. Look at Press, 1989
In the 1950s, computers filled rooms and engineers struggled the top left to see the line of code: “Z(I) = Y + W(I)”. Many lines
with reliability and performance. In the 1960s, performance im- make a computer program. And, thus, a deck of cards.
proved, but computers were still room-sized. It would take the
revolution in mass-produced integrated circuits to change this.
And this happened because of Intercontinental Ballistic Missiles.
You see, something was happening to push our 1960s engineers
to dream up the modern micro-computer.
Analog computers were an option, of course. And analog com-
puters are not an ancient technology — unless I am ancient. When
I studied control theory at the U.S. Air Force Academy from 1972
to 1976, we were using analog computers. There were still plenty
in service and most control systems were still “designed in the s-
plane” and realized with discrete circuits. (Remember that phrase,
you’ll see it later.) This is as opposed to today’s digital control Figure 2: Thanks to Arnold Reinhold for this photo of a FORTRAN
systems using embedded computers. punch card from a deck (creative commons)
I had my “spirule” and I learned the root-locus method for de- Each Minuteman II guidance system needed a couple thousand
signing stable control systems. See figure 1. Texas Instruments integrated circuits and the initial production run
Of course, we also had digital computers at the Academy. In the 1970s, the dream was realized in mass-produced hard- included hundreds of missiles. Thus, ICBMs gave us the first mass-
Well, one digital computer. My programming classes and as- ware and there were digital computers appearing on-board aircraft produced computer. This drove TI production costs down and set the
tronautical engineering classes used the Burroughs 6700. I spent and missiles. The mass production started with the Minuteman II
many nights in the computer room programming it with a language ICBM and its D37C computer. It was roughly the shape of a loaf See VONO, Page 6

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