In those days [batch processing] programmers never even documented their programs, because it was assumed that nobody else would ever use them. Now, however, time-sharing had made exchanging software trivial: you just stored one copy in the public repository and therby effectively gave it to the world. Immediately people began to document their programs and to think of them as being usable by others. They started to build on each other's work.

In those days [batch processing] programmers never even documented their programs, because it was assumed that nobody else would ever use them. Now, however, time-sharing had made exchanging software trivial: you just stored one copy in the public repository and therby effectively gave it to the world. Immediately people began to document their programs and to think of them as being usable by others. They started to build on each other's work.