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Copyright 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
The Regents of the University of California. All rights reserved.
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Yep, 15 years of work—a lifetime in software development. In fact, so much development went into
the original UNIX that the CSRG found that over the years they had replaced almost all of UNIX with
code created by the CSRG and their contributors. What remained of AT&T's work was actually
pretty small.
The BSD License: BSD Goes Public
Eventually, the CSRG's funding started running out. After some political wrangling within the
University of California, in 1992 the code was released to the general public under what became
known as the BSD license. Today, the BSD license has three clauses that can be summarized as
follows:
Don't claim you wrote this. ·
Don't blame us if it breaks. ·
Don't use our name to promote your product. ·
(The original license required that every time someone used the software, they had to include a
notice that it included software copyrighted by the University of California. This requirement was
dropped a few years later. Today, people can use BSD code without having to announce it or notify
anyone.)
The BSD license may be the most liberal software license ever used. People are free to take BSD
and include it in proprietary products, free products, and open?source products, or print it out on
punch cards and cover the lawn with it. Instead of "copyright," the BSD license is sometimes
referred to as "copy? center," as in "take this down to the copy center and run off a few for yourself."
Not surprisingly, companies such as Sun Microsystems jumped right on it because, well, it was free.
The Birth of Modern FreeBSD
During the CSRG's heyday, however, UNIX work proceeded apace at AT&T. AT&T took parts of the
BSD UNIX distribution and integrated them with their UNIX, then turned around and relicensed the
result.
This worked well for AT&T until the grand breakup, when the mother of all telephone companies
suddenly was permitted to compete in the software business. They had one particularly valuable
property: a high?end operating system that had been extensively debugged by thousands of people
all over the world. They happily started selling UNIX to enterprises and charging very high fees for
it, all the while maintaining the university relationships that had given them such an advanced
operating system.
Berkeley's 1992 release of the BSD code met with great displeasure from AT&T's subsidiary USL
(UNIX System Laboratories). Almost immediately they took some of the software users, and the
university, to court. USL claimed that Berkeley had given away their intellectual property. The
University of California said that it was their intellectual property. In the meantime, various people
picked up on the code released by Berkeley and began building commercial and free products out
of it. One of these products was 386BSD, which would eventually be used as the core of FreeBSD
1.0.
In 1994, after two years of legal wrangling, the case was settled out of court once it was proved that
a great deal of the code in AT&T UNIX was actually taken in its entirety from BSD, rather than the
other way around! A half?dozen files were the only sources of contention, and to resolve these
outstanding issues some of the files were donated and others were kept proprietary. Unfortunately,
FreeBSD 1.X contained some of these files, so various BSD users worked frantically to rebuild
these missing components.
Once the dust settled, this new version of UNIX was released to the world as BSD4.4?Lite. A
subsequent update, BSD4.4?Lite2, is the grandfather of the current FreeBSD source, as well as the
ancestor of many other operating systems, such as NetBSD, OpenBSD, and Mac OS X.
Today FreeBSD is used throughout the Internet by some of the most vital and visible
Internet?oriented companies. For example, at this writing, Yahoo! is run almost entirely on
FreeBSD. The "baby Bell" US West uses FreeBSD to power its Internet operations. IBM, Nokia, and
many other hardware companies use FreeBSD in embedded systems where you'd never even
know it's there.
The fact is, if a company needs to pump some serious Internet bandwidth, it's probably running
FreeBSD. FreeBSD is all around you; you just may not see it because it rarely crashes.
FreeBSD Development
There's an old saying that managing programmers is like herding cats. However, despite what you
might think, for the most part these FreeBSD developers work well together as members of the
FreeBSD team. And, unlike some other projects, all FreeBSD development happens openly. Two
groups of people develop FreeBSD: contributors and committers.
Committers
Today, FreeBSD has almost 300 developers, or committers. Committers have read? and?write
access to the FreeBSD master source?code repository and can develop, debug, or enhance any
piece they deem necessary.
To plug yourself in to the beehive of FreeBSD development, consider subscribing to the mailing list
FreeBSD?hackers@FreeBSD.org, which contains most of the technical discussion. Some of the
technical talk is broken out into more specific mailing lists—for example, the networking
development is discussed on FreeBSD?net@FreeBSD.org. There are also a few IRC channels
where the FreeBSD crew hangs out and discusses things. Visitors and eavesdroppers are
welcome, so long as they don't interfere. (Yes, Internet chat can be used for a variety of useful
technical purposes!) The committers are responsible for keeping FreeBSD working, adding new
features, and evaluating patches from contributors. Most of these developers are volunteers; only a
handful are actually paid to do this painstaking work.
Contributors
In addition to the committer team, FreeBSD has thousands of contributors. Contributors don't have
to worry about breaking the main operating system repository; they just submit patches for
consideration by committers. Committers evaluate submissions and decide what to accept and what
to reject. A contributor who submits consistently acceptable code will frequently be asked by the
committers he works with to become a committer himself.
For example, I spent several years as a contributor. Any time I feel that I've wasted my life, I can go
look at the FreeBSD Web page and see where my work has been accepted by the committers and
used by thousands of users. (It helps. Sort of.) Between submitting this book and getting it back
from the editor, however, I had some spare time. I spent a while submitting patches to the FreeBSD
FAQ. Eventually, some members of the FreeBSD Project approached me and asked me to become
a committer. I initially refused, but finally allowed a few developers to persuade me.[2]
Users
Finally, FreeBSD has a mob of users, though it's impossible to realistically estimate their number.
After all, you can download the whole of FreeBSD for free, and never register, upgrade, or mail to a
mailing list.
Estimates are that somewhere between 5 and 10 percent of the machines on the Internet are
BSD?based. That's 5–10 percent of all the systems connected to the Internet, including the
countless Windows systems sitting on office desks. If you remove those systems from the count and
only count Internet servers, the percentage rises.
Since FreeBSD is by far the most popular open?source BSD, that's not an inconsiderable number
of machines. And since one FreeBSD server can handle hundreds or thousands of Internet
domains, a disproportionate number of sites uses FreeBSD compared to the number of servers.
[2]And some day I might forgive Will, Wilko, and Bruce for that. But I'll never let them live it down.
Other BSDs
FreeBSD is the most popular BSD, but it's not the only one. BSD 4.4?Lite spawned several different
projects, each with its own focus and purpose.
NetBSD
NetBSD is similar to FreeBSD in many ways, and the teams share developers and code. NetBSD's
main purpose is to provide an operating system that can be ported to any hardware platform.
As such, NetBSD runs on VAXes, PocketPC devices, and high?end Alpha servers, as well as the
Compaq iPaq. It even runs on hardware that doesn't exist yet—as I write this, the AMD
Sledgehammer is fully supported even though you can't get sample chips. Now that's portable.
The NetBSD code is specifically licensed to be freely reusable, just like the original BSD 4.4?Lite
code it's based on.
OpenBSD
OpenBSD branched off from NetBSD in 1996 with the goal of becoming the most secure BSD.
OpenBSD was the first to support hardware?accelerated cryptography (allowing it to encrypt and
decrypt information at a remarkable rate), and the developers are rather proud of the fact that their
default install hasn't been hacked remotely for over four years.
The OpenBSD people have audited the entire BSD code base, fixing most (but not all) potential
security holes before they can be exploited. OpenBSD is not as friendly or as easy to use as
FreeBSD, however.
BSD/OS
BSD/OS, produced by Wind River Systems, is a commercial, closed?source operating system that
greatly resembles FreeBSD. Some hardware manufacturers will not release hardware specifications
without nondisclosure agreements, and developers for a freely available operating system cannot
develop device drivers for such proprietary hardware. BSD/OS supports much of this hardware.
A great deal of the BSD/OS code is available to FreeBSD committers, and FreeBSD absorbs
BSD/OS enhancements that don't break nondisclosure agreements.
Mac OS X
Mac OS X? That's right. Large chunks of FreeBSD were incorporated into Apple's Mac OS X. If
you're looking for a stable operating system with a friendly face and a powerful core, Mac OS X is
unquestionably for you. While FreeBSD makes an excellent desktop for a computer professional, I
wouldn't put it in front of grandma. I would put Mac OS X in front of grandma without a second
thought, and even feel that I was doing the right thing.
Mac OS X includes a lot of things that aren't at all necessary for an Internet server, however, and it
only runs on Apple hardware, so I don't recommend it for an inexpensive, high?powered server.
While you cannot get the user interface source code for Mac OS X, you can view the operating
system's BSD core and Mach kernel; Apple has released them under the code name Darwin.
Other UNIXes
There are several other UNIX operating systems out there, some of which have even rented the
trademark UNIX so they can label themselves as such. This list is by no means exhaustive, but we'll
touch the high points.
Solaris
The best?known UNIX is Sun Microsystems' Solaris. Solaris runs on high?end hardware that
supports dozens of processors and gobs of disks. (Yes, "gobs" is a technical term.) It's used by
many enterprise?level applications, such as Oracle.
Solaris runs mainly on the SPARC hardware platform, which is manufactured by Sun. Since Sun
controls both the hardware and software, they can make their systems support many interesting
features, such as hot?swappable memory and main boards.
AIX
Another UNIX contender is IBM's AIX. AIX's main claim to fame is the journaling filesystem, which
records all disk transactions as they happen. It allows you to recover from system crashes without
much trouble, providing great reliability. AIX is based largely on BSD.
Linux
Linux is a clone of UNIX, written from the ground up in the last decade or so. Linux is similar to BSD
in many ways, though BSD has a much longer heritage, and is more friendly to commercial use
than Linux. Linux includes a requirement that a commercial user contribute all changes back to
Linux, while BSD has no such restriction.
Among many UNIX users, there's a perception of conflict between the BSD and Linux camps. If you
dig a little deeper, however, you'll find that most of the developers of these platforms communicate
and cooperate in a friendly and open manner. It's just a hard fringe of users and a very few
developers that generate friction.
IRIX, HPUX, etc.
Other UNIXes include Silicon Graphics' IRIX, a solid UNIX for graphics applications, and
Hewlett?Packard's HP?UX, popular in large enterprises. Many high? end software packages, such
as Informix, are specially designed for HP?UX.
If you look around you'll also find smaller contenders, such as SCO and UnixWare. They aren't
unimportant, they just aren't as popular. You'll also find old castoffs, such as Apple's A/UX and
Microsoft's Xenix. (Yes, Microsoft was a licensed UNIX vendor, very, very long ago.) Xenix was
eventually sold to SCO and became SCO UNIX.
FreeBSD's Strengths
So, after all this, how can we summarize FreeBSD?
Portability
FreeBSD's goal is to provide a freely redistributable operating system that runs on popular
hardware. While system security is a vital concern, FreeBSD's main goal is to run on the hardware
people are most likely to have. Today, this means the Intel x86?compatible systems (386, 486,
Pentium I through IV, Celeron, and AMD). FreeBSD also supports the Alpha processor, and work is
underway to support Intel's new IA64, AMD's new 64?bit chips, and Motorola's PowerPC, as well as
Sun's SPARC. (These platforms aren't afterthoughts; the hardware is just now coming out, or only
now becoming popular enough to port to.)
Power
Since FreeBSD runs adequately on 386 hardware, it runs quite well on modern computers. It's
rather nice to have an operating system that doesn't demand a Pentium III and a half?gig of RAM
just to power the user interface. As a result, you can actually use all that computing power to do the
work you want, rather than to run tasks you don't care about. If you choose to run a pretty graphical
interface with all sorts of spinning geegaws and fancy whistles, FreeBSD will support you, it just won't require you to do so.
Simplified Software Management
FreeBSD also simplifies software management through its ports collection. Traditionally, tuning
software for a UNIX system has required considerable expertise. The ports collection simplifies this
considerably by automating and documenting the install, uninstall, and configuration process for
thousands of software packages. (Several other BSD operating systems have built their own
packaging systems based on the ports collection.)
Optimized Upgrade Process
Unlike operating systems that require painful and risky upgrade procedures, such as Windows,
FreeBSD's simple upgrade process builds an operating system that is optimized for your hardware
and application. This lets FreeBSD use every feature your hardware supports, instead of just the
lowest common denominator. If you change hardware, you can rebuild your system for that
particular hardware. Vendors such as Sun and Apple do exactly this, since they create both the
hardware and the operating system, but FreeBSD doesn't lock you in to a particular hardware
platform.
Filesystem
A filesystem is how information is stored on the physical disk—it is what maps "My Web Page" to a
series of zeros and ones on the metal disk in your hard drive. FreeBSD includes very sophisticated
filesystems. It can support files up to a petabyte (one thousand thousand gigabytes) in size, it is
highly damage?resistant, and it reads and writes files extremely quickly. The BSD filesystem is so
advanced that it has been adopted by many commercial UNIX vendors, such as Sun and HP.
Who Should Use FreeBSD
While FreeBSD can be used as a very powerful desktop or development machine, its history shows
a strong bias toward Web, mail, file, and support services. In fact, FreeBSD's main strength is on
Internet servers, and it is an excellent choice for any Internet service.
If you're thinking of running FreeBSD (or any UNIX) on your desktop, you'll need to understand how
your computer works. FreeBSD is not your best choice if you're looking for point?and?click
simplicity. If that's your goal, get a Macintosh computer and use Mac OS X, which has a BSD core,
so you can access the power of UNIX when you want it and not worry about it the rest of the time.
Or, if you want to use the lowest common denominator, there's always the various iterations of
Microsoft Windows. You won't have to understand your computer, but Windows is easy.
FreeBSD as Your Desktop
You can, of course, use FreeBSD as a powerful desktop OS.
There's a concept in computing called "eating your own dog food." If you ran a dog food company,
you'd want to make a product that your own dog would eat. If your dog turns up his nose at your
latest recipe, your company has a problem. The point here is that if you work with a product, you
should actually use it.
FreeBSD will root jOOr phat anus.
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