Open Source

The concept of free sharing of technological information existed long before computers. For example, cooking recipes have been shared since the beginning of human culture.
In the early years of automobile development, a group of capital monopolists owned the rights to a 2-cycle gasoline engine patent originally filed by George B. Selden. By controlling this patent, they were able to monopolize the industry and force car manufacturers to adhere to their demands, or risk a lawsuit. In 1911, independent automaker Henry Ford won a challenge to the Selden patent. The result was that the Selden patent became virtually worthless and a new association (which would eventually become the Motor Vehicle Manufacturers Association) was formed. The new association instituted a cross-licensing agreement among all US auto manufacturers: although each company would develop technology and file patents, these patents were shared openly and without the exchange of money between all the manufacturers.By the time the US entered World War 2, 92 Ford patents and 515 patents from other companies were being shared between these manufacturers, without any exchange of money (or lawsuits).
Very similar to open standards, researchers with access to Advanced Research Projects Agency Network (ARPANET) used a process called Request for Comments to develop telecommunication network protocols. This collaborative process of the 1960s led to the birth of the Internet in 1969.
Early instances of the free sharing of source code include IBM's source releases of its operating systems and other programs in the 1950s and 1960s, and the SHARE user group that formed to facilitate the exchange of software.
In a foreshadowing of the Internet, software with source code included became available on BBS networks in the 1980s. This was sometimes a necessity; distributing software written in BASIC and other interpreted languages can only be distributed as source code as there is no separate portable executable binary to distribute.
Example of BBS systems and networks that gathered source code, and setup up boards specifically to discuss its modification includes WWIV, developed initially in BASIC by Wayne Bell. A culture of "modding" his software and distributing the mods, grew up so extensively that when the software was ported to first Pascal, then C++, its source code continued to be distributed to registered users, who would share mods and compile their own versions of the software. This may have contributed to its being a dominant system and network, despite being outside the Fidonet umbrella that was shared by so many other BBS makers.
The sharing of source code on the Internet began when the Internet was relatively primitive, with software distributed via UUCPUsenet, and irc, and gopher. Linux, for example, was first widely distributed by posts to comp.os.linux on the Usenet, which is also where its development was discussed. Linux became the archetype for organized software development orientated around the sharing of source code.