FreeBSD Handbook
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1.2 Welcome to FreeBSD!

FreeBSD is a 4.4BSD-Lite based operating system for the Intel architecture (x86) and DEC Alpha based systems. Ports to other architectures are also underway. For a brief overview of FreeBSD, see the next section. You can also read about the history of FreeBSD, or the current release. If you are interested in contributing something to the Project (code, hardware, unmarked bills), see the Contributing to FreeBSD article.

1.2.1 What Can FreeBSD Do?

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 SLIP, PPP, NFS, DHCP, and NIS. 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) and was designed as such from the ground up.
The industry standard X Window System (X11R6) 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++, Fortran, and Perl 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 the 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:
- FTP servers
- World Wide Web servers (standard or secure [SSL])
- Firewalls and NAT (``IP masquerading'') gateways
- Electronic Mail servers
- USENET News or Bulletin Board Systems
- 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, either using the freely available XFree86 server or one of the excellent commercial servers provided by X Inside. 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 and via anonymous FTP. Please see Appendix A for more information about obtaining FreeBSD.

1.2.2 Who uses FreeBSD?

FreeBSD is used to power some of the biggest sites on the Internet, including:

and many more.