Unix experience at the University of California in Berkeley started in 1974 on a PDP 11/45 shared between several departments, one of which wanted to run DEC's RSTS operating system instead and had the clout to make it stick for about 16 hours per day. The remaining eight hours a day were enough, however, to grow a research commitment to interactive Unix processing leading, by the fall of 1975, to the purchase of a PDP 11/70 dedicated to "instructional Unix" and the appearance on campus of UCB graduate Ken Thompson, on teaching sabbatical from Bell Labs.
Thompson brought both the latest Unix release and full source with him. In doing that he continued, despite muted objections from some in AT&T management, the academic tradition of free information exchange - a tradition that, for Unix, went directly back to MIT and the original Multics designers but more generally goes back all the way to the freedom of information corolary to the re-invention and formulation of the scientific method in Elizabethan England.
The results at UCB, of course, speak for themselves; but there was conflict over the software's commercial value even then and much of open source licensing's subsequent evolution has been driven by people taking different positions on the same "morals versus money" and "current versus futures" trade-offs made then.
At that time the academic, open publication, tradition became the clear winner; but the trade-off was that the source materials would only be open for teaching and research uses in academia - so the University of Alberta later got a Unix tape for a PDP11/44 but I couldn't use it in work for an aerospace contractor.
Since then the generic BSD license has evolved largely to ward off attacks on its basic premise: that anyone should be able to use the knowledge gained in research provided that sources are both fully acknowledged and correctly represented.
Thus when Sun released their Network File System the licensing and related contractual restrictions were largely designed simply to head off Microsoft's generic embrace, extend, and extinguish strategy - a success Sun later repeated with the first Java licenses and agreements.
Richard Stallman forked this process in the late seventies with what has since become the Free Software Foundation's (FSF) Gnu Public License (GPL) by adding riders intended to deny people from outside the open source community the opportunity to use open source for corporate commercial advantage.
Since then many things have changed - particularly with respect to the application of patent law to software in the United States, through intellectual property fatwas by bureaucrats in Brussels, and because of the accumulating effects of litigation and sharp dealing by players ranging in scale from the government of communist China to the lawyers representing Red Hat.
And the licenses, of course, have had to evolve with external change - thus Sun's CDD license now represents the state of the art on the BSD side, the GPL3 proposal represents leading edge compromise at the Free Software Foundation, and the dozens of other widely used variants represent the trade-offs, customisations, and accommodations appropriate to their proponents.
I want to discuss one aspect of the FSF's political agenda tomorrow and the CDDL on Thursday, but two things are clear: the differences are much less important than the similarities, and both evolved from the same base, under the same pressures, and in support of broadly similar goals.