Newswise — Four decades ago, Ken Thompson, the late Dennis Ritchie, and others at AT&T's Bell Laboratories developed Unix, which turned out to be one of the most influential pieces of software ever written. Their work on this operating system had to be done on the sly, though, because their employer had recently backed away from operating-systems research.

After Thompson and others reported about their new operating system to the academic community in the early 1970s, they received many requests for copies, which put AT&T in a bind. Legal constraints prevented the company from entering the computer-software business. AT&T responded by issuing Unix for a nominal fee and allowing licensees access to the source code, but the company refrained from supporting Unix as a product. So Unix users banded together for mutual support and to improve the system, in a manner that very much resembles how the open-source community works today. The result was a proliferation of Unix versions and derivatives, including the operating systems that run much of today's digital equipment, from smart-phones to supercomputers.