open source software

Bob writes program X that does function Z. He gives copies of the source code to Frank and Joe. They make improvements and send copies back to Bob and to two other guys. This continues for a while, and before you know it, Bob's program is infinitely better than Bill's program. (Bill kept his program all to himself and made people pay to use it.) The result is low cost, high quality software for everyone. Yay!

Software for which the source code is made available to users.

"Many users of the GNU/Linux system will not have heard the ideas of free software. They will not be aware that we have ideas, that a system exists because of ethical ideals, which were omitted from ideas associated with the term 'open source.'"
—Richard Stallman

Richard Stallman is occasionally a controversial figure in the computing world, but one thing i do salute about him is his defence of the Four freedoms of software. He considers software free only if the user has the freedom to run the program as they wish, for any purpose. . Then there is the freedom to study the program and modify it, the freedom to distribute copies of the program to others, and finally the freedom to distribute modified versions of the program. the example given by modulus above, really describes what Stallman calls free, open source software

the open source movement does not always require or guarantee these freedoms, even where the source code is available. Stallman considers the open source initiative weak for these reasons, and i do tend to agree with him. The many 'open source' licences do not always permit the kinds of freedom Stallman preaches. it's why he never uses the term 'open source', rather using 'free' and 'libre' in conjunction.

Requested by C-Dawg and delivered with pleasure.

$ xclip -o | wc -w
205