[roguecoder]

When computer programming first became a thing mostly women had been taught to type. Men would dictate, women would type things up. Think Mad Men.

It was assumed that programming would be basically the same thing. Male mathematicians would write up algorithms and women would type them up. If you read math papers that relied on computer calculation from the 50's and 60's you'll often see women's names in the acknowledgments for having programmed the algorithms.

As it became clear that it was a more involved job, men began moving into the field. Someone else in these comments listed the books that describe the process.