What is BSD?

BSD stands for “Berkeley Software Distribution”. It is the name of distributions of source code from the University of California, Berkeley, which were originally extensions to AT&T's Research UNIX operating system. Several open source operating system projects are based on a release of this source code known as 4.4BSD-Lite. In addition, they comprise a number of packages from other Open Source projects, including notably the GNU project. The overall operating system comprises:

• The BSD kernel, which handles process scheduling, memory management, symmetric multi-processing (SMP), device drivers, etc.
  Unlike the Linux kernel, there are several different BSD kernels with differing capabilities.
  
• The C library, the base API for the system.
  The BSD C library is based on code from Berkeley, not the GNU project.
  
• Utilities such as shells, file utilities, compilers and linkers.
  Some of the utilities are derived from the GNU project, others are not.
  
• The X Window system, which handles graphical display.
  The X Window system used in most versions of BSD is maintained by the X.Org project. FreeBSD allows the user to choose from a variety of desktop environments, such as Gnome, KDE, or Xfce; and lightweight window managers like Openbox, Fluxbox, or Awesome.
  
• Many other programs and utilities.
  
  
  CREDITS:http://www.freebsd.org/doc/en/articles/explaining-bsd/