Definition: BSD

(Berkeley Software Distribution) The software distribution facility of the Computer Systems Research Group (CSRG) of the University of California at Berkeley. CSRG helped develop the TCP/IP protocols for DARPA and the ARPAnet and released them in the early 1980s along with the Unix source code from AT&T. BSD charged for the media, and a license from AT&T was required for use. Throughout the 1980s, this operating system release from BSD was known as "BSD Unix."

Bill Joy ran the group until 1982 when he co-founded Sun Microsystems, bringing 4.2BSD with him as the foundation of SunOS. The last BSD version released by BSD was 4.4BSD.

Many Offshoots
In the 1990s, the AT&T kernel was removed from the BSD release, and several different groups developed new kernels to replace the AT&T code.

BSD/386 and BSD/OS
In 1991, former CSRG members founded Berkeley Software Design, Inc., Colorado Springs, CO, and released BSD/386 for the Intel platform. A decade later, Wind River Systems acquired BSDI's software assets and turned the OS into its BSD/OS Internet Server product.

FreeBSD, NetBSD and OpenBSD
FreeBSD is the most widely used open source BSD operating system. It runs on Intel and Alpha platforms and is known for its ease of use. NetBSD runs on the greatest number of platforms, and OpenBSD is the most security-oriented. OpenBSD evolved from NetBSD and also runs on a variety of hardware.