FreeBSD has many noteworthy features. Some of these are:
· Preemptive multitasking with dynamic priority adjustment to ensure smooth and fair sharing of the computer between applications and users, even under the heaviest of loads.
· Multi-user facilities which allow many people to use a FreeBSD system simultaneously for a variety of things. This means, for example, that system peripherals such as printers and tape drives are properly shared between all users on the system or the network and that individual resource limits can be placed on users or groups of users, protecting critical system resources from over-use.
· Strong TCP/IP networking with support for industry standards such as SCTP, DHCP, NFS, NIS, PPP, SLIP, IPsec, and IPv6. This means that your FreeBSD machine can interoperate easily with other systems as well as act as an enterprise server, providing vital functions such as NFS (remote file access) and email services or putting your organization on the Internet with WWW, FTP, routing and firewall (security) services.
· Memory protection ensures that applications (or users) cannot interfere with each other. One application crashing will not affect others in any way.
· FreeBSD is a 32-bit operating system (64-bit on the Alpha, Itanium, AMD64, and UltraSPARC) and was designed as such from the ground up.
· The industry standard X Window System (X11R7) provides a graphical user interface (GUI) for the cost of a common VGA card and monitor and comes with full sources.
· Binary compatibility with many programs built for Linux, SCO, SVR4, BSDI and NetBSD.
· Thousands of ready-to-run applications are available from the FreeBSD ports and packages collection. Why search the net when you can find it all right here?
· Thousands of additional and easy-to-port applications are available on the Internet. FreeBSD is source code compatible with most popular commercial UNIX® systems and thus most applications require few, if any, changes to compile.
· Demand paged virtual memory and “merged VM/buffer cache” design efficiently satisfies applications with large appetites for memory while still maintaining interactive response to other users.
· SMP support for machines with multiple CPUs.
· A full complement of C, C++, and Fortran development tools. Many additional languages for advanced research and development are also available in the ports and packages collection.
· Source code for the entire system means you have the greatest degree of control over your environment. Why be locked into a proprietary solution at the mercy of your vendor when you can have a truly open system?
· Extensive online documentation.
· And many more!
FreeBSD is based on the 4.4BSD-Lite release from Computer Systems Research Group (CSRG) at the University of California at Berkeley, and carries on the distinguished tradition of BSD systems development. In addition to the fine work provided by CSRG, the FreeBSD Project has put in many thousands of hours in fine tuning the system for maximum performance and reliability in real-life load situations. As many of the commercial giants struggle to field PC operating systems with such features, performance and reliability, FreeBSD can offer them now!
The applications to which FreeBSD can be put are truly limited only by your own imagination. From software development to factory automation, inventory control to azimuth correction of remote satellite antennae; if it can be done with a commercial UNIX product then it is more than likely that you can do it with FreeBSD too! FreeBSD also benefits significantly from literally thousands of high quality applications developed by research centers and universities around the world, often available at little to no cost. Commercial applications are also available and appearing in greater numbers every day.
Because the source code for FreeBSD itself is generally available, the system can also be customized to an almost unheard of degree for special applications or projects, and in ways not generally possible with operating systems from most major commercial vendors. Here is just a sampling of some of the applications in which people are currently using FreeBSD:
· Internet Services: The robust TCP/IP networking built into FreeBSD makes it an ideal platform for a variety of Internet services such as:
o FTP servers
o World Wide Web servers (standard or secure [SSL])
o IPv4 and IPv6 routing
o Firewalls and NAT (“IP masquerading”) gateways
o Electronic Mail servers
o USENET News or Bulletin Board Systems
o And more…
With FreeBSD, you can easily start out small with an inexpensive 386 class PC and upgrade all the way up to a quad-processor Xeon with RAID storage as your enterprise grows.
· Education: Are you a student of computer science or a related engineering field? There is no better way of learning about operating systems, computer architecture and networking than the hands on, under the hood experience that FreeBSD can provide. A number of freely available CAD, mathematical and graphic design packages also make it highly useful to those whose primary interest in a computer is to get other work done!
· Research: With source code for the entire system available, FreeBSD is an excellent platform for research in operating systems as well as other branches of computer science. FreeBSD’s freely available nature also makes it possible for remote groups to collaborate on ideas or shared development without having to worry about special licensing agreements or limitations on what may be discussed in open forums.
· Networking: Need a new router? A name server (DNS)? A firewall to keep people out of your internal network? FreeBSD can easily turn that unused 386 or 486 PC sitting in the corner into an advanced router with sophisticated packet-filtering capabilities.
· X Window workstation: FreeBSD is a fine choice for an inexpensive X terminal solution, using the freely available X11 server. Unlike an X terminal, FreeBSD allows many applications to be run locally if desired, thus relieving the burden on a central server. FreeBSD can even boot “diskless”, making individual workstations even cheaper and easier to administer.
· Software Development: The basic FreeBSD system comes with a full complement of development tools including the renowned GNU C/C++ compiler and debugger.
FreeBSD is available in both source and binary form on CDROM, DVD, and via anonymous FTP. Please see Appendix A for more information about obtaining FreeBSD.
The FreeBSD project had its genesis in the early part of 1993, partially as an outgrowth of the “Unofficial 386BSD Patchkit” by the patchkit’s last 3 coordinators: Nate Williams, Rod Grimes and myself.
Our original goal was to produce an intermediate snapshot of 386BSD in order to fix a number of problems with it that the patchkit mechanism just was not capable of solving. Some of you may remember the early working title for the project being “386BSD 0.5” or “386BSD Interim” in reference to that fact.
386BSD was Bill Jolitz’s operating system, which had been up to that point suffering rather severely from almost a year’s worth of neglect. As the patchkit swelled ever more uncomfortably with each passing day, we were in unanimous agreement that something had to be done and decided to assist Bill by providing this interim “cleanup” snapshot. Those plans came to a rude halt when Bill Jolitz suddenly decided to withdraw his sanction from the project without any clear indication of what would be done instead.
It did not take us long to decide that the goal remained worthwhile, even without Bill’s support, and so we adopted the name “FreeBSD”, coined by David Greenman. Our initial objectives were set after consulting with the system’s current users and, once it became clear that the project was on the road to perhaps even becoming a reality, I contacted Walnut Creek CDROM with an eye toward improving FreeBSD’s distribution channels for those many unfortunates without easy access to the Internet. Walnut Creek CDROM not only supported the idea of distributing FreeBSD on CD but also went so far as to provide the project with a machine to work on and a fast Internet connection. Without Walnut Creek CDROM’s almost unprecedented degree of faith in what was, at the time, a completely unknown project, it is quite unlikely that FreeBSD would have gotten as far, as fast, as it has today.
The first CDROM (and general net-wide) distribution was FreeBSD 1.0, released in December of 1993. This was based on the 4.3BSD-Lite (“Net/2”) tape from U.C. Berkeley, with many components also provided by 386BSD and the Free Software Foundation. It was a fairly reasonable success for a first offering, and we followed it with the highly successful FreeBSD 1.1 release in May of 1994.
Around this time, some rather unexpected storm clouds formed on the horizon as Novell and U.C. Berkeley settled their long-running lawsuit over the legal status of the Berkeley Net/2 tape. A condition of that settlement was U.C. Berkeley’s concession that large parts of Net/2 were “encumbered” code and the property of Novell, who had in turn acquired it from AT&T some time previously. What Berkeley got in return was Novell’s “blessing” that the 4.4BSD-Lite release, when it was finally released, would be declared unencumbered and all existing Net/2 users would be strongly encouraged to switch. This included FreeBSD, and the project was given until the end of July 1994 to stop shipping its own Net/2 based product. Under the terms of that agreement, the project was allowed one last release before the deadline, that release being FreeBSD 22.214.171.124.
FreeBSD then set about the arduous task of literally re-inventing itself from a completely new and rather incomplete set of 4.4BSD-Lite bits. The “Lite” releases were light in part because Berkeley’s CSRG had removed large chunks of code required for actually constructing a bootable running system (due to various legal requirements) and the fact that the Intel port of 4.4 was highly incomplete. It took the project until November of 1994 to make this transition, at which point it released FreeBSD 2.0 to the net and on CDROM (in late December). Despite being still more than a little rough around the edges, the release was a significant success and was followed by the more robust and easier to install FreeBSD 2.0.5 release in June of 1995.
We released FreeBSD 2.1.5 in August of 1996, and it appeared to be popular enough among the ISP and commercial communities that another release along the 2.1-STABLE branch was merited. This was FreeBSD 126.96.36.199, released in February 1997 and capping the end of mainstream development on 2.1-STABLE. Now in maintenance mode, only security enhancements and other critical bug fixes will be done on this branch (RELENG_2_1_0).
FreeBSD 2.2 was branched from the development mainline (“-CURRENT”) in November 1996 as the RELENG_2_2 branch, and the first full release (2.2.1) was released in April 1997. Further releases along the 2.2 branch were done in the summer and fall of ’97, the last of which (2.2.8) appeared in November 1998. The first official 3.0 release appeared in October 1998 and spelled the beginning of the end for the 2.2 branch.
The tree branched again on Jan 20, 1999, leading to the 4.0-CURRENT and 3.X-STABLE branches. From 3.X-STABLE, 3.1 was released on February 15, 1999, 3.2 on May 15, 1999, 3.3 on September 16, 1999, 3.4 on December 20, 1999, and 3.5 on June 24, 2000, which was followed a few days later by a minor point release update to 3.5.1, to incorporate some last-minute security fixes to Kerberos. This will be the final release in the 3.X branch.
There was another branch on March 13, 2000, which saw the emergence of the 4.X-STABLE branch. There have been several releases from it so far: 4.0-RELEASE was introduced in March 2000, and the last 4.11-RELEASE came out in January 2005.
The long-awaited 5.0-RELEASE was announced on January 19, 2003. The culmination of nearly three years of work, this release started FreeBSD on the path of advanced multiprocessor and application thread support and introduced support for the UltraSPARC® and ia64 platforms. This release was followed by 5.1 in June of 2003. The last 5.X release from the -CURRENT branch was 5.2.1-RELEASE, introduced in February 2004.
The RELENG_5 branch, created in August 2004, was followed by 5.3-RELEASE, which marked the beginning of the 5-STABLE branch releases. The most recent 6.3-RELEASE came out in Jan 2008. There will be no additional releases from the RELENG_5 branch.
The tree was branched again in July 2005, this time for RELENG_6. 6.0-RELEASE, the first release of the 6.X branch, was released in November 2005. The most recent 7.0-RELEASE came out in Feb 2008. There will be additional releases from the RELENG_6 branch.
For now, long-term development projects continue to take place in the 7.X-CURRENT (trunk) branch, and SNAPshot releases of 7.X on CDROM (and, of course, on the net) are continually made available from the snapshot server as work progresses.
1.3.2 FreeBSD Project Goals
Contributed by Jordan Hubbard.
The goals of the FreeBSD Project are to provide software that may be used for any purpose and without strings attached. Many of us have a significant investment in the code (and project) and would certainly not mind a little financial compensation now and then, but we are definitely not prepared to insist on it. We believe that our first and foremost “mission” is to provide code to any and all comers, and for whatever purpose, so that the code gets the widest possible use and provides the widest possible benefit. This is, I believe, one of the most fundamental goals of Free Software and one that we enthusiastically support.
That code in our source tree which falls under the GNU General Public License (GPL) or Library General Public License (LGPL) comes with slightly more strings attached, though at least on the side of enforced access rather than the usual opposite. Due to the additional complexities that can evolve in the commercial use of GPL software we do, however, prefer software submitted under the more relaxed BSD copyright when it is a reasonable option to do so.
1.3.3 The FreeBSD Development Model
Contributed by Satoshi Asami.
The development of FreeBSD is a very open and flexible process, being literally built from the contributions of hundreds of people around the world, as can be seen from our list of contributors. FreeBSD’s development infrastructure allow these hundreds of developers to collaborate over the Internet. We are constantly on the lookout for new developers and ideas, and those interested in becoming more closely involved with the project need simply contact us at the FreeBSD technical discussions mailing list. The FreeBSD announcements mailing list is also available to those wishing to make other FreeBSD users aware of major areas of work.
Useful things to know about the FreeBSD project and its development process, whether working independently or in close cooperation:
The CVS repository
The central source tree for FreeBSD is maintained by CVS (Concurrent Versions System), a freely available source code control tool that comes bundled with FreeBSD. The primary CVS repository resides on a machine in Santa Clara CA, USA from where it is replicated to numerous mirror machines throughout the world. The CVS tree, which contains the -CURRENT and -STABLE trees, can all be easily replicated to your own machine as well. Please refer to the Synchronizing your source tree section for more information on doing this.
The committers list
The committers are the people who have write access to the CVS tree, and are authorized to make modifications to the FreeBSD source (the term “committer” comes from the cvs(1) commit command, which is used to bring new changes into the CVS repository). The best way of making submissions for review by the committers list is to use the send-pr(1) command. If something appears to be jammed in the system, then you may also reach them by sending mail to the FreeBSD committer’s mailing list.
The FreeBSD core team
The FreeBSD core team would be equivalent to the board of directors if the FreeBSD Project were a company. The primary task of the core team is to make sure the project, as a whole, is in good shape and is heading in the right directions. Inviting dedicated and responsible developers to join our group of committers is one of the functions of the core team, as is the recruitment of new core team members as others move on. The current core team was elected from a pool of committer candidates in July 2006. Elections are held every 2 years.
Some core team members also have specific areas of responsibility, meaning that they are committed to ensuring that some large portion of the system works as advertised. For a complete list of FreeBSD developers and their areas of responsibility, please see the Contributors List
Note: Most members of the core team are volunteers when it comes to FreeBSD development and do not benefit from the project financially, so “commitment” should also not be misconstrued as meaning “guaranteed support.” The “board of directors” analogy above is not very accurate, and it may be more suitable to say that these are the people who gave up their lives in favor of FreeBSD against their better judgement!
Last, but definitely not least, the largest group of developers are the users themselves who provide feedback and bug fixes to us on an almost constant basis. The primary way of keeping in touch with FreeBSD’s more non-centralized development is to subscribe to the FreeBSD technical discussions mailing list where such things are discussed. See Appendix C for more information about the various FreeBSD mailing lists.
The FreeBSD Contributors List is a long and growing one, so why not join it by contributing something back to FreeBSD today?
Providing code is not the only way of contributing to the project; for a more complete list of things that need doing, please refer to the FreeBSD Project web site.
In summary, our development model is organized as a loose set of concentric circles. The centralized model is designed for the convenience of the users of FreeBSD, who are provided with an easy way of tracking one central code base, not to keep potential contributors out! Our desire is to present a stable operating system with a large set of coherent application programs that the users can easily install and use — this model works very well in accomplishing that.
All we ask of those who would join us as FreeBSD developers is some of the same dedication its current people have to its continued success!