It had actually started to sell a commercial version of its UNIX operating system and this commonly became known as system 5 and there’s a whole reason for that.
To do with different versions that came before it but it was called system 5 now at the same time the people at Berkeley were also continuing to develop the UNIX sources that they got way back when AT&T.
Were licensing the sources and this led to a flavor of units called the BSD version because it’s from the Berkeley software.
Distribution and so by the mid 80s you’ve now got two versions of UNIX running you’ve got system 5 from 80 itself and you’ve got BSD from California now from these 2 branches various important and well-known versions of UNIX were spawned for example hp-ux and Solaris come from the system 5 kind of inheritance and operate systems like ultrix which was from dec Digital Equipment.
Corporation came from the bsd line now of course over time the various different things that were being developed in these top racism were cross ported the most important one was that networking first of all came to the BSD distribution and eventually that made its way over into system 5 of course all.
This source code is still under the source code license that came from tea when they originally sold it to the various universities so over time the BSD virtual started to replace the files that came from AT&T with their own version so it became separated from the system five version eventually in the university of california side to release.
Publicly the source code for its version of the operate is ‘m and it said it was free from all AT&T files of course there was a lawsuit and we’re now in the early 90s you’ve got the university of california vs. AT&T and ultimately the lawsuit was dropped and what came out of that protest was a version called bsd 4.4 light which is meant to be a version of unix which has no source files that recently came from AT&T now this version of bsd then.
Went on to create what we have today which is freebsd and various other operating systems including in part mac OS which we’ll talk about in a moment now the upshot of all this is that two important things happened one is that we now have a defined UNIX philosophy so the.
Idea of you write one program and it does one thing really well the idea that a program it’s output could become the input to another program which is the idea of pipes the idea of how you compile programs and how the command line works this has.
All been defined because of system 5 and because of BSD and the other thing that happened is that they wanted compatibility between the versions so there started to be published a range of standards the most popular one being POSIX which actually says that if your program is to compile on.
This operating system it has to have these api’s that have these particular functions so you’ve got the POSIX specification which redefined what UNIX does from a programming point of view now while all this was going on there are several other things that were happening in parallel that we need to know about Wiley is the start of the new foundation good.