Rear Admiral Grace Murray Hopper (December 9, 1906 – January 1, 1992) is known as the developer of the compiler, one of the first programmers of Harvard Mark I computer (one of the earliest electro-mechanical computers) and the popularizer of the term ‘debugging’.
She was a curious person from childhood (for example, taking alarm clocks apart to see how they work). She had a PhD in mathematics and taught it in university for a while.
In 1943 she left university in favour of WAVES; the all-women division of US Navy. She didn’t see battle, but served in Navy Reserve and worked on Harvard Mark I.
While she was working on MARK II (the successor to Mark I) there was a moth stuck in the machine, disrupting its work. She called the process of removing the moth ‘debugging’. It’s not quite sure if she is the inventor of the word ‘computer bug’, but she certainly popularized it.
In 1949 she joined the team developing UNIVAC I (the first commercial computer). Three years later her compiler, a program translating source code written in a programming language to machine code, was ready and working. Her co-workers were surprised by that, believing that computers could only do arithmetic.
She was also part of the team that developed COBOL, one of the first programming languages. She believed that computer programs should be written in a language similar to the way humans speak, not in machine code or assembler language that are easy for a computer to understand, but much tougher for human programmers.
She suggested that large centralized computer systems should be replaced by networks of smaller computers and that computer languages should conform to standards.
She retired from the Navy in the age of 79.
There are a supercomputer and a Navy destroyer named for her.
"The most important thing I’ve accomplished, other than building the compiler, is training young people. They come to me, you know, and say, “Do you think we can do this?” I say, “Try it.” And I back ‘em up. They need that. I keep track of them as they get older and I stir ‘em up at intervals so they don’t forget to take chances."