Berkeley Software Distribution - Significant BSD Descendants

Significant BSD Descendants

See also: Comparison of BSD operating systems

BSD has been the base of a large number of operating systems. Most notable among these today are perhaps the major open source BSDs: FreeBSD, NetBSD and OpenBSD, which are all derived from 386BSD and 4.4BSD-Lite by various routes. Both NetBSD and FreeBSD started life in 1993, initially derived from 386BSD, but in 1994 migrating to a 4.4BSD-Lite code base. OpenBSD was forked in 1995 from NetBSD. The three most notable descendants in current use—sometimes known as the BSDs—have themselves spawned a number of children, including DragonFly BSD, FreeSBIE, MirOS BSD, DesktopBSD, and PC-BSD. They are targeted at an array of systems for different purposes and are common in government facilities, universities and in commercial use. A number of commercial operating systems are also partly or wholly based on BSD or its descendants, including Sun's SunOS and Apple Inc.'s Mac OS X.

Most of the current BSD operating systems are open source and available for download, free of charge, under the BSD License, the most notable exception being Mac OS X. They also generally use a monolithic kernel architecture, apart from Mac OS X and DragonFly BSD which feature hybrid kernels. The various open source BSD projects generally develop the kernel and userland programs and libraries together, the source code being managed using a single central source repository.

In the past, BSD was also used as a basis for several proprietary versions of UNIX, such as Sun's SunOS, Sequent's Dynix, NeXT's NeXTSTEP, DEC's Ultrix and OSF/1 AXP (now Tru64 UNIX). Of these, only the last is still currently supported in its original form. Parts of NeXT's software became the foundation for Mac OS X, among the most commercially successful BSD variants in the general market.

A selection of significant Unix versions and Unix-like operating systems that descend from BSD includes:

• FreeBSD, a major open source effort focusing on performance and the x86 platform.
  • DragonFly BSD, a fork of FreeBSD to follow an alternative design, particularly related to SMP.
  • PC-BSD and DesktopBSD, distributions of FreeBSD with emphasis on ease of use and user friendly interfaces for the desktop/laptop PC user.
  • FreeNAS a free network-attached storage server based on a minimal version of FreeBSD.
  • Nokia IPSO (IPSO SB variant), the FreeBSD-based OS used in Nokia Firewall Appliances.
  • Juniper Networks JunOS, the operating system for Juniper routers, a customized version of FreeBSD, and a variety of other embedded operating systems
  • NeXT NEXTSTEP and OPENSTEP, based on the Mach kernel and 4BSD; the ancestor of Mac OS X
    • Apple Inc.'s Darwin, the core of Mac OS X and iOS; built on the XNU kernel (part Mach, part FreeBSD, part Apple-derived code) and a userland much of which comes from FreeBSD
  • Isilon Systems' OneFS, the operating system used on Isilon IQ-series clustered storage systems, is a heavily customized version of FreeBSD.
  • NetApp's ONTAP GX, the operating system for NetApp filers, is a customized version of FreeBSD with the ONTAP GX architecture built on top.
• NetBSD, an open source BSD with an emphasis on portability and clean design.
  • OpenBSD, a 1995 fork of NetBSD, focuses on portability, standardization, correctness, proactive security and integrated cryptography.
• F5 Networks, F5 BIGIP Appliances used a BSD OS as the management OS until version 9.0 was released, which is built on top of Linux.
• DEC's Ultrix, the official version of Unix for its PDP-11, VAX, and DECstation systems
• OSF/1, a microkernel-based UNIX developed by the Open Software Foundation, incorporating the Mach kernel and parts of 4BSD
  • Tru64 UNIX (formerly DEC OSF/1 AXP or Digital UNIX), the port of OSF/1 for DEC Alpha-based systems from DEC, Compaq and HP.
• Early versions of Sun Microsystems SunOS (up to SunOS 4.1.4), an enhanced version of 4BSD for the Sun Motorola 68k-based Sun-2 and Sun-3 systems, SPARC-based systems, and x86-based Sun386i systems.
• 386BSD, the first open source BSD-based operating system and the ancestor of most current BSD systems
• DEMOS, a Soviet BSD clone
• BSD/OS, a (now defunct) proprietary BSD for PCs