Margaret Hamilton

The second book in the Mirador series, ONES AND ZEROES, is dedicated to Margaret Hamilton. You may know her from this photo, which gets passed around the Internet a lot:

That’s Hamilton standing next to the source code for the Apollo mission, which she coded herself, and which is credited not only with landing the astronauts on the moon but saving their lives in the process. Along the way, she invented modern software, coined the term “software engineering,” and in 2016 was awarded the Presidential Medal of Honor: the highest award a civilian can receive from the American government. In short, she’s amazing.

This morning I got an email from a “70-year-old retired computer guy.” With his permission, I share portions of that email here, because it shines an even brighter light on one of the heroes of modern technology:

I am just starting ONES AND ZEROES and I read your wonderful dedication. I am in a position to provide some additional information. Here goes –

The first computer I wrote code for was an IBM 7094. It is a slightly souped up version of the 7090 that was featured in the movie and book [editor’s note: Hidden Figures]. Let me acquaint you with some of its technical specifications.

It had 32,768 words of “ferrite core” memory. A word was 36 bits long and could be divided into 6 6-bit characters. (The machine also supported “integer” and “floating point” arithmetic.) This is the bit-for-bit equivalent of 144 KB of RAM. On a character-for-character basis, it is equivalent to 192 KB. The original Apple II and the Commodore 64 each had 64 KB of RAM. So it had more RAM than those boxes. But when I bought my first IBM PC in 1981 I opted to add something called an AST “6-pack” card. This allowed me to have 256 KB of RAM. So my first PC had more memory than did a 7090/7094.

Ferrite core memory (tiny magnetic donuts with wires strung through them by hand) was quite slow. The clock time was typically quoted as 2,000 microseconds (1/500th of a second). That is memory speed but processor speed was comparable. And when IBM announced the first “System 360” computers in 1964 for delivery in 1965 the price they quoted for memory was a dollar per byte. So the stuff was frightfully expensive back then.

The machine came with a nice “FORTRAN 4” compiler. FORTRAN is still the go to language for engineering/scientific work. So NASA is still running a lot of FORTRAN and I’m sure Ms. Hamilton cranked out quite a bit of it her day. You could also write programs in “machine language” or “machine code” (the same thing). In that case you used a program called MAP (Macro-Assembly Program).

My point in all this is to give you even more of a flavor of how hard it was for her to do what she did. She had to write tight (not much memory to deal with) fast (the machine was probably slower than your first home computer) code with very little in the way of tools and aids. And she couldn’t write just one program. It would have been too big to fit. She probably had to write dozens, perhaps hundreds of programs. And, as you said, they HAD to work. Lives (and the prestige of the U. S.) depended on it.

So I applaud your choice. And I too have a soft spot for the other Margaret Hamilton.

And if you are interested in women in computing, especially in the early days, check out Grace Murray Hopper. She is every bit as interesting as Margaret Hamilton. Here’s just one of dozens of Hopper stories –

She was working with a team of people back in the vacuum tube days of computers. As I said, vacuum tubes are essentially high tech light bulbs. And computers of the time used thousands of them. And like light bulbs they occasionally burn out. With so many, “occasionally” turned out to be something like once per day. So a necessary tool back in the day was a dental mirror. It would be used to poke into tight spaces looking for dark tubes. One day Hopper was using a dental mirror to hunt down a problem. She found not a dark tube but a moth. The moth had died of electrocution brought on by bridging the gap between two contacts. Hopper removed the moth thus restoring the computer to health. She then pasted the moth into the log book kept to document the operation of the machine and added an explanation of what had happened. And that’s why software errors are now called “bugs”.

The Mirador series is about girls who are gamers, coders, and hackers, so I’ve taken the opportunity with each book to dedicate them to some of the amazing women in tech. The first book was Hedy Lamar, the second was Hamilton, and now for the third I really wracked my brain, trying to come up with the perfect choice. I considered Grace Hopper, as mentioned above; I considered Katherine Johnson, newly famous thanks to HIDDEN FIGURES; I considered all kinds of women in all kinds of fields. Eventually, though, I went back to the beginning: not just the first woman to write a computer program, but the first human being to write one. She was so far ahead of the game that computers didn’t even technically exist yet–she wrote a full program for a hypothetical device theorized by Charles Babbage.

Ada Lovelace, this one’s for you.

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