Their initial goal was simply to operatetheir DEC PDP machines more effectively. In 1971, UNIX became multi-user andmulti-tasking, but it was still just being developed by a small group ofprogrammers who were trying to take advantage of the machines they had at hand. (In other words, this operating system that they were developing did not run onany machine made by Bell!)In 1973, Dennis Ritchie rewrote the UNIX operating system in C (a language hehad developed. ) And in 1975, the portability of the C programming language wasused to “port” UNIX to a wide variety of hardware platforms. For legal reasons,Bell Labs was not able to market UNIX in the 1970’s, though they did share thisoperating system with many universities – most notably UC-Berkeley. This led tosome of the variations in UNIX which we see today.
After the divestiture of theBell System, their parent company, AT&T, became much more interested inmarketing a commercial version of UNIX. And today we see that many companieshave now licensed their own version:AT&T’s System V,Versions of System V such as SCO’s Xenix and IBM’s AIXBerkeley’s UNIX (called “BSD” for “Berkeley System Development”),Versions of Berkeley UNIX such as Sun Microsystem’s SunOS, DEC’s Ultrix andCarnegie Mellon University’s Mach(used on the NEXT).Category: Technology