Information AboutFreebsd |
| CATEGORIES ABOUT FREEBSD | |
| freebsd | |
| free software operating systems | |
| computing platforms | |
| operating system securityfreebsd | |
| free software operating systems | |
| computing platforms | |
| operating system security | |
| bsd | |
FreeBSD is a Unix-like Free Operating System descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through the 386BSD and 4.4BSD operating systems. It runs on Intel X86 Family (IA-32) PC Compatible systems (including the Microsoft Xbox 1), and also DEC Alpha , Sun UltraSPARC , IA-64 , AMD64 , PowerPC and NEC PC-98 architectures. Support for the ARM and MIPS architectures are under development. FreeBSD is developed as a complete operating system. The Kernel , Device Driver s and all of the Userland utilities, such as the Shell , are held in the same Source Code Revision Tracking tree ( CVS ). This is in contrast to other free operating systems such as Linux where the kernel, userland utilities and applications are developed separately and packaged together by other groups as Linux Distribution s. As an operating system, FreeBSD is generally regarded as reliable and robust, and of the operating systems that accurately report Uptime remotely,2 FreeBSD is the most common free operating system listed in Netcraft's list3 of the 50 Web Server s with the longest uptime. A long uptime also indicates that no Crashes have occurred and that no kernel updates have been deemed necessary, as installing a new Kernel requires a reboot and resets the uptime counter of the system. HISTORY AND DEVELOPMENT : the BSD Daemon ]] Initial Development of FreeBSD started in 1993, originating in the unofficial '' Patchkit '' maintained by users of the 386BSD operating system. The first official release of FreeBSD was FreeBSD 1.0 in December 1993. However, due to concerns about the legality of the BSD Net/2 release source code used in 386BSD and a consequent lawsuit between Novell (then owner of the UNIX copyright) and Berkeley, FreeBSD ended up re-engineering much of the system using the 4.4BSD-Lite release from the University Of California, Berkeley , with the FreeBSD 2.0 release in January 1995. The FreeBSD Handbook includes more information about the genesis of FreeBSD. Perhaps FreeBSD 2.0's most notable advance was the revamp of the original Carnegie Mellon University Mach Virtual Memory system, which was optimized for performance under high loads, and the creation of the FreeBSD Ports system that made downloading, building and installing third party software very easy. FreeBSD powered extremely successful sites like Cdrom.com (a huge repository of software that broke several throughput records on the Internet), Hotmail , and Yahoo! . FreeBSD 3.0 brought many changes: it switched to the ELF Binary format and initial support for SMP systems and the 64 bit Alpha platform were added. At its time, the 3.X branch was severely criticized as many changes were not evidently beneficial and affected performance, but it was a necessary step to develop what would become the very successful 4.X branch. Initially, FreeBSD employed the BSD Daemon as its logo, but in 2005 a competition for a new logo was arranged. On October 8 2005 , the competition finished and the design by Anton K. Gural was chosen as the new FreeBSD logo.4 The BSD Daemon will remain as the FreeBSD Project mascot. FREEBSD 5 DEVELOPMENT AND CHANGES The latest and final FreeBSD release from the 5-STABLE branch is 5.5, and was released in May 2006. FreeBSD Developer s maintain (at least) two branches of simultaneous development. A ''-STABLE'' branch of FreeBSD is created for each major version number, from which releases are cut about once every 4-6 months. The latest 4-STABLE release of FreeBSD is 4.11, which is the last of the 4-STABLE branch releases. The first 5-STABLE release was 5.3 (5.0 through 5.2.1 were cut from ''-CURRENT''). The first 6-STABLE release was 6.0. The development branch, ''-CURRENT'', is now 7.0-CURRENT, which contains aggressive new kernel and userspace features. If a feature is sufficiently stable and mature, it is eventually Backport ed ("MFC" - Merge from CURRENT in the FreeBSD developer slang) to the ''-STABLE'' branch. FreeBSD's development model is described in an in-depth article by Niklas Saers.5 The largest architectural change in FreeBSD 5 was a major change in the low-level kernel locking mechanisms to enable better symmetric multiprocessor (SMP) support, releasing much of the kernel from the MP lock, sometimes referred to as the ''Giant Lock''. It is now possible for more than one process to execute in kernel mode at the same time. Other major changes include an ''m'':''n'' threading solution called related. A project called "TrustedBSD" was launched by Robert Watson for the purpose of adding security lock-down frameworks functionality to the FreeBSD operating system (this is not related to " Trusted Computing "). An extensible Mandatory Access Control framework (the TrustedBSD MAC Framework), filesystem Access Control List s (ACLs), enhanced PAM support ( OpenPAM ) and the new UFS2 filesystem all came from TrustedBSD. Some of the TrustedBSD functionality has been integrated into the NetBSD and OpenBSD operating systems as well. This work was supported through sponsorship by DARPA . FreeBSD 5 also significantly changed the block I/O layer with the introduction of the GEOM modular disk I/O request transformation framework, contributed by Poul-Henning Kamp . GEOM enables the simple creation of many kinds of functionality, such as mirroring (gmirror) and encryption ( GBDE and GELI). This work was supported through sponsorship by DARPA . The 5.4 and 5.5 releases of FreeBSD have confirmed the FreeBSD 5.x branch as a highly stable and well-performing release, albeit one with a long gestation period due to the large feature set. FREEBSD 6 The FreeBSD 6 release series is the current ''-STABLE'' development series. FreeBSD 6.2 was released on , created by the TrustedBSD Project (based on the BSM implementation found in Apple's Open Source Darwin ) and released under a BSD-style License . FREEBSD 7 FreeBSD 7 is currently under development, with the first release scheduled for 2007. Features currently under development include: SCTP , Network Stack virtualization, UFS Journaling , a port of Sun 's ZFS file system, GCC4 , support for the ARM and MIPS Architectures and major updates relating to audio, USB and the scheduler. LINUX COMPATIBILITY FreeBSD provides binary Compatibility with several other Unix-like Operating System s, including Linux . This permits Linux programs to be run, including some commercial applications distributed only in binary form. Applications which use the Linux compatibility layer include StarOffice , the Linux version of Firefox , Adobe Acrobat , RealPlayer , VMware , Oracle , Mathematica , Matlab , WordPerfect , Skype , Doom 3 and Quake 4 6. There is said to be no noticeable performance penalty when running Linux binaries over native FreeBSD programs, and they may even be faster than the same binaries running on Linux. However, the layer is not completely seamless and some Linux binaries are unusable on FreeBSD or possess limited functionality: this is often as the compatibility layer only supports the system calls available in the historical Linux kernel 2.4.2, work is ongoing to provide Linux 2.6 support. LICENSE FreeBSD is released under a variety of licenses. All of the kernel code and most newly created code is released under the two-clause BSD License , which allows everyone to use and redistribute FreeBSD as they wish. There are also parts under the GPL , LGPL , ISC , CDDL , and Beerware licenses, as well as three- and four-clause BSD licenses. In addition, some device drivers include a Binary Blob , such as the Atheros HAL . DERIVATIVES A wide variety of products are directly or indirectly based on FreeBSD. These range from Embedded devices, such as Juniper Networks routers, Ironport network security appliances, Nokia 's firewall operating system, NetApp 's OnTap GX, Panasas 's and Isilon Systems 's cluster storage operating systems, NetASQ security appliances, St Bernard iPrism web filtering appliances, to portions of other Operating Systems including Linux and the RTOS VxWorks . Darwin , the core of Apple's Mac OS X , borrows heavily from FreeBSD, including its virtual file system, network stack and components of its Userspace . Apple continues to integrate new code from and contribute changes back to FreeBSD. The open source OpenDarwin , originally derived from Apple's codebase but now a separate entity, also includes substantial FreeBSD code. In addition, there are a number of operating systems originally Forked from or based on FreeBSD including PC-BSD and DesktopBSD , which include enhancements aimed at home users and workstations; the FreeSBIE and Frenzy Live CD distributions; the M0n0wall and PfSense embedded firewalls; and DragonFly BSD , a fork from FreeBSD 4.8 aiming for a different multiprocessor synchronization strategy than that chosen for FreeBSD 5 and development of some Microkernel features. TRUSTEDBSD The TrustedBSD project provides a set of trusted operating system extensions to FreeBSD. It was begun primarily by Robert Watson with the goal of implementing concepts from the Common Criteria for Information Technology Security Evaluation and the Orange Book . The project still continues, and many of its extensions have been integrated into FreeBSD. The main focuses of the TrustedBSD project are Access Control List s (ACLs), security event auditing, extended file system attributes, fine-grained Capabilities , and Mandatory Access Control s (MAC). The project has also ported the NSA 's FLASK /TE implementation from SELinux to FreeBSD. Other work includes the development of OpenBSM , an open source implementation of Sun's Basic Security Module (BSM) API and audit log file format, which supports an extensive security audit system. This was shipped as part of FreeBSD 6.2. Other infrastructure work in FreeBSD performed as part of the TrustedBSD Project has included SYN Cookies , GEOM, and OpenPAM. While most components of the TrustedBSD project are eventually folded into the main sources for FreeBSD, many features, once fully matured, find their way into other operating systems. For example, OpenPAM and UFS2 have been adopted by NetBSD , and the TrustedBSD MAC Framework and TrustedBSD Audit implementation have been adopted by Apple Computer for Mac OS X . GOVERNANCE STRUCTURE The FreeBSD Project is run by FreeBSD committers, or developers who have CVS commit access. Committers come in several flavours, including source committers (base operating system), doc committers (documentation and web site authors) and ports (third party application porting and infrastructure). Every two years, the FreeBSD committers elect a 9-member FreeBSD Core Team, who are responsible for overall project direction, setting and enforcing project rules, and approving new "commit bits", or the granting of CVS commit access. A number of responsibilities are officially assigned to other development teams by the FreeBSD Core Team, including responsibility for security advisories (the Security Officer Team), release engineering (the Release Engineering Team), and managing the ports collection (the Port Manager team). Developers may give up their commit rights to retire or for "safe-keeping" after a period of a year or more of inactivity, although commit rights will generally be restored on request (both of which have happened a moderate number of times in over 12 years of development). Under rare circumstances, commit rights may be removed by Core Team vote as a result of repeated violation of project rules and standards. The FreeBSD Project is unusual among open source projects in having developers who have worked with its source base for over 25 years, as a result of the involvement of a number of past University of California developers who worked on BSD at the CSRG . REFERENCES SEE ALSO
FURTHER READING
EXTERNAL LINKS
|
|
|