A Brief History of FreeBSD and UNIX
| The original UNIX operating system was developed at AT&T Bell Laboratories. Two AT&T engineersKen Thompson and Dennis Ritchiewere the main driving forces behind the UNIX project. The origins of UNIX can probably be traced to the spring of 1969. It was an offshoot of a largely unsuccessful effort by a conglomeration of companies to develop a "time-sharing" operating system, one in which a mainframe system's limited computing resources could be shared among many different users logged in simultaneously from remote terminals. The operating system that this consortium developed was called MULTICS; although it introduced many innovative features and created the template for what we think of today as a multiuser operating system, it never achieved any commercial success to speak of, and AT&T's Bell Labs pulled out of the project. Ken Thompson, one of the members of the AT&T team working on MULTICS, continued in the same spirit by writing (with the help of Ritchie and others) a new operating system, similar to MULTICS but smaller and simpler, for the DEC PDP-7 minicomputer instead of expensive mainframes as before. Its name, UNIX, evoked the new system's simplicity in comparison to the sprawling MULTICS. To support and underpin the new system, Thompson and Ritchie developed a new programming language called C, which made development far faster than prior efforts (which had relied on the DEC assembly language specific to the PDP-7). The C programming language and UNIX (also, interchangeably, Unix) are two of the most important developments in the history of the computer, not least because C was the first "portable" programming languageit allowed applications (written in C) to be ported to other types of computer platforms relatively easily. Because UNIX was written in C, it was itself also portable and could be made to run on other types of computer platforms with comparatively little effort. This breakthrough, seemingly unremarkable from a modern perspective, was what led to the meteoric rise in popularity of UNIX and the software development tradition we take for granted today. Note If it weren't for a game called "Space Travel" that he was writing in his spare time for the GE-645 mainframe computer (the platform for MULTICS), Ken Thompson might never have been inspired to write UNIX in the first place. BSD Is BornBecause AT&T Bell Laboratories was not really in the business of selling computer operating systems, it licensed the UNIX operating system and its source code to various academic institutions relatively cheaply. One of the institutions that did a lot of early work on UNIX was the Computer Systems Research Group (CSRG) at the University of California at Berkeley. The CSRG made some very important contributions to UNIX, including the development of the UNIX File System (UFS) and the addition of the TCP/IP networking stack. Eventually, the CSRG made so many changes to UNIX that it released its own version, known as the Berkeley Software Distribution. Note Contrary to popular belief, CSRG did not do the first port of UNIX to the DEC VAX. The first VAX port was done at AT&T Bell Labs, but this port did not support the VAX's virtual memory system. CSRG thus undertook the task of porting BSD UNIX to the VAX, in the process adding support for the platform's virtual memory architecture. CSRG made much of the BSD source code available to the public for free, and a CSRG engineer by the name of Bill Jolitz ported BSD to the Intel x86 platform in 1991. The port was called 386BSD. In addition, Jolitz and some of his colleagues from CSRG formed a commercial spin-off company named Berkeley Software Distribution, Incorporated (BSDi), and sold a commercial version of BSD that included source code. FreeBSD Is BornIn 1993, two groups of developers became dissatisfied with the direction in which Bill and Lynne Jolitz were taking 386BSD, and they took the freely available, stagnant source code andas would become a tradition in the open-source community for many years to comestarted doing their own work on it. The first of these groups was FreeBSD, which focused on making the system as easy as possible to use for nontechnical users and directed its efforts primarily upon Intel x86 hardware. A second group, NetBSD, started work slightly later; it sought to bring BSD to every possible hardware platform. If it even slightly resembles a computer, chances are that you'll be able to run NetBSD on it. OpenBSD, a third group that dedicated itself to being the most secure operating system available, split off from the NetBSD group somewhat later. Today, FreeBSD is the most popular of the BSD-based, UNIX-like operating systems, largely because of its generalist approach and wide applicability to everyday tasks. The modern FreeBSD is a full-fledged operating system that's suitable for everything from the most security-sensitive, performance-demanding server applications to the most userfocused, graphics-intensive productivity applications on the desktop. Since the release of FreeBSD 5.4 in 2005, the FreeBSD project has split once again and spawned PC-BSD, a flavor of FreeBSD specifically dedicated to desktop applications. Tip If you're interested in FreeBSD as a desktop operating system, look into PC-BSD; information is available at http://www.pcbsd.org. PC-BSD is in an early stage of development at the time of this writing. The history of FreeBSD and UNIX is one of the most challenging, yet fascinating, studies in the computing industry, and it's far more complex than has been described here. Numerous lawsuits, changes of philosophical direction, cross-pollination of code, splits, merges, new projects, and abandoned efforts litter any exhaustive account of this ongoing tale. The following links are invaluable sources of information on the subject:
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