Rise of the Rocket Girls by Nathalia Holt

Author:Nathalia Holt
Language: eng
Format: epub
Publisher: Little, Brown and Company
Published: 2016-04-04T16:00:00+00:00

Punch cards used by the women to write programs

Most of the computers had never used a typewriter—only secretaries at JPL used those—and didn’t even know how to type. But they quickly learned how to work the keypunch. Just as each number on the keypad of a phone can be used to type in letters, the keypunch used a code to translate each letter of FORTRAN into a number. When Helen pressed A on the keypunch, the machine loudly leaped into action, feeding the card into the machine and punching a hole in the 7 on the card. Line by line as Helen typed her commands into the keypunch, the letters transformed into a punched pattern. If she made a single mistake on the keypunch there was no salvaging it; the card had to be thrown away, and she had to start over with a fresh card.

When Helen had accurately entered the full set of commands from her notebook, she wasn’t quite done yet. She still had to compile her code. Just as is done today, Helen’s source code—written in her programming language, FORTRAN—had to be compiled so that the computer could recognize it in its own language, the binary code of zeroes and ones. Each line of assembly code translated into one instruction in binary machine code. While Helen could translate the punches in the cards into the equations they stood for, the IBMs could not. She had to run all the cards through a special machine called a compiler.

Navy rear admiral Grace Brewster Murray Hopper and her team at Remington Rand, in New York City, produced the first compiler in 1952. That machine, the A-0, and later the A-2, translated mathematics into computer code. Hopper knew that for digital computers to become mainstream, people couldn’t be expected to write in binary code. Instead she had to find a way to communicate between humans and computers. The compiler was the answer: a translator between man and machine. It was the beginning of computer languages.

The compiler technology was brand-new and had to be specific to each computer language. “Nobody knew anything. They [compilers] didn’t exist! Everything we did we invented on the fly,” said Lois Haibt, a programmer at IBM who built the core of the FORTRAN compiler in the late 1950s.

Helen ran her cards through the FORTRAN compiler, which then produced a second set of cards containing the running program in a language the IBM could understand. The first set of cards was for her; she and the other women could pass them back and forth and see how the code had been written. The second set of cards was only for the IBM. This deck was then loaded into the computer, which would run the operations and give Helen the output she needed. When it was all done, Helen put the cards away in cardboard boxes. You never knew when you might need to run the program again.

The engineers viewed the IBMs with suspicion, while the women embraced the new technology, largely because of their hands-on experience in using the machines.

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