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90-584: OpenSSI is based on the Linux operating system and was released as an open source project by Compaq in 2001. It is the final stage of a long process of development, stretching back to LOCUS , developed in the early 1980s. OpenSSI allows a cluster of individual computers ( nodes ) to be treated as one large system. Processes run on any node have full access to the resources of all nodes. Processes can be migrated from node to node automatically to balance system utilization. Inbound network connections can be directed to

180-860: A Linux distribution (distro), which includes the kernel and supporting system software and libraries — many of which are provided by the GNU Project — to create a complete operating system. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses and recommends the name " GNU/Linux " to emphasize the use and importance of GNU software in many distributions, causing some controversy . Thousands of distributions exist, many based directly or indirectly on other distributions; popular Linux distributions include Debian , Fedora Linux , Arch Linux , and Ubuntu , while commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise . Other than

270-472: A high-level language implementation of Unix made its porting to different computer platforms easier. Due to an earlier antitrust case forbidding it from entering the computer business, AT&T licensed the operating system's source code as a trade secret to anyone who asked. As a result, Unix grew quickly and became widely adopted by academic institutions and businesses. In 1984, AT&T divested itself of its regional operating companies , and

360-424: A minimalist functionality, while more elaborate window managers such as FVWM , Enlightenment , or Window Maker provide more features such as a built-in taskbar and themes , but are still lightweight when compared to desktop environments. Desktop environments include window managers as part of their standard installations, such as Mutter (GNOME), KWin (KDE), or Xfwm (xfce), although users may choose to use

450-505: A solution stack such as LAMP . The source code of Linux may be used, modified, and distributed commercially or non-commercially by anyone under the terms of its respective licenses, such as the GNU General Public License (GPL). The license means creating novel distributions is permitted by anyone and is easier than it would be for an operating system such as MacOS or Microsoft Windows . The Linux kernel, for example,

540-734: A stateful protocol. Version 4 became the first version developed with the Internet Engineering Task Force (IETF) after Sun Microsystems handed over the development of the NFS protocols. NFS version 4.1 (RFC 5661, January 2010; revised in RFC 8881, August 2020) aims to provide protocol support to take advantage of clustered server deployments including the ability to provide scalable parallel access to files distributed among multiple servers (pNFS extension). Version 4.1 includes Session trunking mechanism (Also known as NFS Multipathing) and

630-466: A competing OS, agrees that "Linux wasn't designed, it evolved", but considers this to be a limitation, proposing that some features, especially those related to security, cannot be evolved into, "this is not a biological system at the end of the day, it's a software system." A Linux-based system is a modular Unix-like operating system, deriving much of its basic design from principles established in Unix during

720-971: A different window manager if preferred. Wayland is a display server protocol intended as a replacement for the X11 protocol; as of 2022 , it has received relatively wide adoption. Unlike X11, Wayland does not need an external window manager and compositing manager. Therefore, a Wayland compositor takes the role of the display server, window manager, and compositing manager. Weston is the reference implementation of Wayland, while GNOME's Mutter and KDE's KWin are being ported to Wayland as standalone display servers. Enlightenment has already been successfully ported since version 19. Additionally, many window managers have been made for Wayland, such as Sway or Hyprland, as well as other graphical utilities such as Waybar or Rofi. Linux currently has two modern kernel-userspace APIs for handling video input devices: V4L2 API for video streams and radio, and DVB API for digital TV reception. Due to

810-487: A manner that every node has direct access to the file system. OpenSSI provides a single process space – every process is visible from every node, and can be managed from any node using the normal Linux commands (ps, kill, renice and so on). The Linux /proc virtual filesystem shows all running processes on all nodes. The implementation of the single process space is accomplished using the VPROC abstraction invented by Locus for

900-419: A method of separating the filesystem meta-data from file data location; it goes beyond the simple name/data separation by striping the data amongst a set of data servers. This differs from the traditional NFS server which holds the names of files and their data under the single umbrella of the server. Some products are multi-node NFS servers, but the participation of the client in separation of meta-data and data

990-404: A place in server installations such as the popular LAMP application stack. The use of Linux distributions in home and enterprise desktops has been growing. Linux distributions have also become popular in the netbook market, with many devices shipping with customized Linux distributions installed, and Google releasing their own ChromeOS designed for netbooks. Linux's greatest success in

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1080-498: A popular CLI shell. The graphical user interface (or GUI) used by most Linux systems is built on top of an implementation of the X Window System . More recently, the Linux community has sought to advance to Wayland as the new display server protocol, in place of X11. Many other open-source software projects contribute to Linux systems. Installed components of a Linux system include the following: The user interface , also known as

1170-432: A pressing issue. At the time of introduction of Version 3, vendor support for TCP as a transport-layer protocol began increasing. While several vendors had already added support for NFS Version 2 with TCP as a transport, Sun Microsystems added support for TCP as a transport for NFS at the same time it added support for Version 3. Using TCP as a transport made using NFS over a WAN more feasible, and allowed

1260-481: A significant business around Linux distributions. The free software licenses , on which the various software packages of a distribution built on the Linux kernel are based, explicitly accommodate and encourage commercialization; the relationship between a Linux distribution as a whole and individual vendors may be seen as symbiotic . One common business model of commercial suppliers is charging for support, especially for business users. A number of companies also offer

1350-459: A similar agreement to give ISOC change control over NFS, although writing the contract carefully to exclude NFS version 2 and version 3. Instead, ISOC gained the right to add new versions to the NFS protocol, which resulted in IETF specifying NFS version 4 in 2003. By the 21st century, neither DFS nor AFS had achieved any major commercial success as compared to SMB or NFS. IBM, which had formerly acquired

1440-493: A specialized business version of their distribution, which adds proprietary support packages and tools to administer higher numbers of installations or to simplify administrative tasks. Another business model is to give away the software to sell hardware. This used to be the norm in the computer industry, with operating systems such as CP/M , Apple DOS , and versions of the classic Mac OS before 7.6 freely copyable (but not modifiable). As computer hardware standardized throughout

1530-972: A system's software from one central location. A distribution is largely driven by its developer and user communities. Some vendors develop and fund their distributions on a volunteer basis, Debian being a well-known example. Others maintain a community version of their commercial distributions, as Red Hat does with Fedora , and SUSE does with openSUSE . In many cities and regions, local associations known as Linux User Groups (LUGs) seek to promote their preferred distribution and by extension free software. They hold meetings and provide free demonstrations, training, technical support, and operating system installation to new users. Many Internet communities also provide support to Linux users and developers. Most distributions and free software / open-source projects have IRC chatrooms or newsgroups . Online forums are another means of support, with notable examples being Unix & Linux Stack Exchange , LinuxQuestions.org and

1620-402: A user may interact with the application; however, certain extensions of the X Window System are not capable of working over the network. Several X display servers exist, with the reference implementation, X.Org Server , being the most popular. Server distributions might provide a command-line interface for developers and administrators, but provide a custom interface for end-users, designed for

1710-453: A vast body of work and may include both kernel modules and user applications and libraries. Linux vendors and communities combine and distribute the kernel, GNU components, and non-GNU components, with additional package management software in the form of Linux distributions. Many developers of open-source software agree that the Linux kernel was not designed but rather evolved through natural selection . Torvalds considers that although

1800-515: Is a distributed file system protocol originally developed by Sun Microsystems (Sun) in 1984, allowing a user on a client computer to access files over a computer network much like local storage is accessed. NFS, like many other protocols, builds on the Open Network Computing Remote Procedure Call (ONC RPC) system. NFS is an open IETF standard defined in a Request for Comments (RFC), allowing anyone to implement

1890-437: Is available for various Linux distributions . The OpenSSI kernel is distribution independent but various distribution specific Linux user level systems need to be modified, for example the init process and the system startup scripts. In 2010 the most recent supported Linux distributions were: Since 2008, work was in progress to port OpenSSI to Debian Etch and Lenny distributions. The origins of OpenSSI date back to

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1980-504: Is available in some enterprise solutions as VMware ESXi . NFS version 4.2 (RFC 7862) was published in November 2016 with new features including: server-side clone and copy, application I/O advise, sparse files, space reservation, application data block (ADB), labeled NFS with sec_label that accommodates any MAC security system, and two new operations for pNFS (LAYOUTERROR and LAYOUTSTATS). One big advantage of NFSv4 over its predecessors

2070-487: Is available on: During the development of the ONC protocol (called SunRPC at the time), only Apollo's Network Computing System (NCS) offered comparable functionality. Two competing groups developed over fundamental differences in the two remote procedure call systems. Arguments focused on the method for data-encoding — ONC's External Data Representation (XDR) always rendered integers in big-endian order, even if both peers of

2160-562: Is licensed under the GPLv2, with an exception for system calls that allows code that calls the kernel via system calls not to be licensed under the GPL. Because of the dominance of Linux-based Android on smartphones , Linux, including Android, has the largest installed base of all general-purpose operating systems as of May 2022 . Linux is, as of March 2024 , used by around 4 percent of desktop computers . The Chromebook , which runs

2250-429: Is limited. The NFSv4.1 pNFS server is a set of server resources or components; these are assumed to be controlled by the meta-data server. The pNFS client still accesses one meta-data server for traversal or interaction with the namespace; when the client moves data to and from the server it may directly interact with the set of data servers belonging to the pNFS server collection. The NFSv4.1 client can be enabled to be

2340-437: Is that only one UDP or TCP port, 2049, is used to run the service, which simplifies using the protocol across firewalls. WebNFS , an extension to Version 2 and Version 3, allows NFS to integrate more easily into Web-browsers and to enable operation through firewalls. In 2007 Sun Microsystems open-sourced their client-side WebNFS implementation. Various side-band protocols have become associated with NFS. Note: NFS

2430-403: Is that the Linux kernel and other components are free and open-source software. Linux is not the only such operating system, although it is by far the most widely used. Some free and open-source software licenses are based on the principle of copyleft , a kind of reciprocity: any work derived from a copyleft piece of software must also be copyleft itself. The most common free software license,

2520-577: Is the Bourne-Again Shell (bash), originally developed for the GNU Project, other shells such as Zsh are also used. Most low-level Linux components, including various parts of the userland , use the CLI exclusively. The CLI is particularly suited for automation of repetitive or delayed tasks and provides very simple inter-process communication . On desktop systems, the most popular user interfaces are

2610-468: Is typically built into the firmware and is highly tailored to the system. This includes routers , automation controls, smart home devices , video game consoles , televisions (Samsung and LG smart TVs ), automobiles (Tesla, Audi, Mercedes-Benz, Hyundai, and Toyota), and spacecraft ( Falcon 9 rocket, Dragon crew capsule, and the Ingenuity Mars helicopter). The Unix operating system

2700-415: Is used on a wide variety of devices including PCs, workstations , mainframes and embedded systems . Linux is the predominant operating system for servers and is also used on all of the world's 500 fastest supercomputers . When combined with Android , which is Linux-based and designed for smartphones , they have the largest installed base of all general-purpose operating systems . The Linux kernel

2790-475: Is used to manage the /dev directory. Each node runs its own copy of udev to create the appropriate device nodes in a subdirectory of /dev, /dev/1 for node 1, /dev/2 for node 2 and so on. OpenSSI provides internode access to all the standard Linux inter-process communication mechanisms, shared memory , semaphores , SYSV message queues, pipes and Unix domain sockets . In order to implement cluster wide shared memory – distributed shared memory – OpenSSI uses

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2880-708: The Distributed Computing Environment (DCE) and the DCE Distributed File System (DFS) over Sun/ONC RPC and NFS. DFS used DCE as the RPC, and DFS derived from the Andrew File System (AFS); DCE itself derived from a suite of technologies, including Apollo's NCS and Kerberos . Sun Microsystems and the Internet Society (ISOC) reached an agreement to cede "change control" of ONC RPC so that

2970-421: The Free Software Foundation and wrote the GNU General Public License (GNU GPL) in 1989. By the early 1990s, many of the programs required in an operating system (such as libraries, compilers , text editors , a command-line shell , and a windowing system ) were completed, although low-level elements such as device drivers , daemons , and the kernel , called GNU Hurd , were stalled and incomplete. Minix

3060-736: The GNU toolchain , which includes the GNU Compiler Collection (GCC) and the GNU Build System . Amongst others, GCC provides compilers for Ada , C , C++ , Go and Fortran . Many programming languages have a cross-platform reference implementation that supports Linux, for example PHP , Perl , Ruby , Python , Java , Go , Rust and Haskell . First released in 2003, the LLVM project provides an alternative cross-platform open-source compiler for many languages. Proprietary compilers for Linux include

3150-470: The GUI shells , packaged together with extensive Desktop environments , such as KDE Plasma , GNOME , MATE , Cinnamon , LXDE , Pantheon , and Xfce , though a variety of additional user interfaces exist. Most popular user interfaces are based on the X Window System, often simply called "X". It provides network transparency and permits a graphical application running on one system to be displayed on another where

3240-723: The Intel C++ Compiler , Sun Studio , and IBM XL C/C++ Compiler . BASIC is available in procedural form from QB64 , PureBasic , Yabasic , GLBasic , Basic4GL , XBasic , wxBasic , SdlBasic , and Basic-256 , as well as object oriented through Gambas , FreeBASIC , B4X, Basic for Qt , Phoenix Object Basic, NS Basic , ProvideX, Chipmunk Basic , RapidQ and Xojo . Pascal is implemented through GNU Pascal , Free Pascal , and Virtual Pascal , as well as graphically via Lazarus , PascalABC.NET , or Delphi using FireMonkey (previously through Borland Kylix ). Network File System (protocol) Network File System ( NFS )

3330-487: The OSF/1 AD operating system. OpenSSI allows migration of running processes between nodes. When running processes are migrated they continue to have access to any open files, IPC objects or network connections. Processes can be manually migrated, either by the process calling the special OpenSSI migrate(2) system call, or by writing a node number to a special file in the processes /proc directory. Processes may also, if

3420-539: The Open Software Foundation (OSF) in 1988. Ironically, Sun and AT&T had formerly competed over Sun's NFS versus AT&T's Remote File System (RFS), and the quick adoption of NFS over RFS by Digital Equipment, HP, IBM, and many other computer vendors tipped the majority of users in favor of NFS. NFS interoperability was aided by events called "Connectathons" starting in 1986 that allowed vendor-neutral testing of implementations with each other. OSF adopted

3510-476: The shell , is either a command-line interface (CLI), a graphical user interface (GUI), or controls attached to the associated hardware, which is common for embedded systems. For desktop systems, the default user interface is usually graphical, although the CLI is commonly available through terminal emulator windows or on a separate virtual console . CLI shells are text-based user interfaces, which use text for both input and output. The dominant shell used in Linux

3600-399: The 1970s and 1980s. Such a system uses a monolithic kernel , the Linux kernel, which handles process control, networking, access to the peripherals , and file systems . Device drivers are either integrated directly with the kernel or added as modules that are loaded while the system is running. The GNU userland is a key part of most systems based on the Linux kernel, with Android being

3690-451: The 1980s, it became more difficult for hardware manufacturers to profit from this tactic, as the OS would run on any manufacturer's computer that shared the same architecture. Most programming languages support Linux either directly or through third-party community based ports . The original development tools used for building both Linux applications and operating system programs are found within

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3780-446: The CFS token system. At any one time a memory segment may be readable by one or more nodes, or writable by one node. If a node without write access to a segment tries to write then the segment is marked unreadable on all other nodes and writable on the current node. If a node without read access tries to read a segment then the current value is copied from a node where it was valid and if it

3870-663: The GNU General Public License (GPL), is a form of copyleft and is used for the Linux kernel and many of the components from the GNU Project. Linux-based distributions are intended by developers for interoperability with other operating systems and established computing standards. Linux systems adhere to POSIX, SUS , LSB , ISO , and ANSI standards where possible, although to date only one Linux distribution has been POSIX.1 certified, Linux-FT. Free software projects, although developed through collaboration , are often produced independently of each other. The fact that

3960-607: The ISOC's engineering-standards body, the Internet Engineering Task Force (IETF), could publish standards documents (RFCs) related to ONC RPC protocols and could extend ONC RPC. OSF attempted to make DCE RPC an IETF standard, but ultimately proved unwilling to give up change control. Later, the IETF chose to extend ONC RPC by adding a new authentication flavor based on Generic Security Services Application Program Interface (GSSAPI), RPCSEC GSS , to meet IETF requirements that protocol standards have adequate security. Later, Sun and ISOC reached

4050-460: The Linux kernel, key components that make up a distribution may include a display server (windowing system) , a package manager , a bootloader and the Bash shell . Linux is one of the most prominent examples of free and open-source software collaboration. While originally developed for x86 based personal computers , it has since been ported to more platforms than any other operating system, and

4140-647: The Linux kernel-based ChromeOS , dominates the US K–12 education market and represents nearly 20 percent of sub-$ 300 notebook sales in the US. Linux is the leading operating system on servers (over 96.4% of the top one million web servers' operating systems are Linux), leads other big iron systems such as mainframe computers , and is used on all of the world's 500 fastest supercomputers (as of November 2017 , having gradually displaced all competitors). Linux also runs on embedded systems , i.e., devices whose operating system

4230-605: The Linux kernel. On July 3, 1991, to implement Unix system calls , Linus Torvalds attempted unsuccessfully to obtain a digital copy of the POSIX standards documentation with a request to the comp.os.minix newsgroup . After not finding the POSIX documentation, Torvalds initially resorted to determining system calls from SunOS documentation owned by the university for use in operating its Sun Microsystems server. He also learned some system calls from Tanenbaum's Minix text. Torvalds began

4320-466: The beginning, it was rather casually hacked on by huge numbers of volunteers coordinating only through the Internet. Quality was maintained not by rigid standards or autocracy but by the naively simple strategy of releasing every week and getting feedback from hundreds of users within days, creating a sort of rapid Darwinian selection on the mutations introduced by developers." Bryan Cantrill , an engineer of

4410-447: The complexity and diversity of different devices, and due to the large number of formats and standards handled by those APIs, this infrastructure needs to evolve to better fit other devices. Also, a good userspace device library is the key to the success of having userspace applications to be able to work with all formats supported by those devices. The primary difference between Linux and many other popular contemporary operating systems

4500-444: The concept of a public filehandle (null for NFSv2, zero-length for NFSv3) which could be used as the starting point. Both of those changes have later been incorporated into NFSv4. Version 4 (RFC 3010, December 2000; revised in RFC 3530, April 2003 and again in RFC 7530, March 2015), influenced by Andrew File System (AFS) and Server Message Block (SMB), includes performance improvements, mandates strong security, and introduces

4590-724: The connection had little-endian machine-architectures, whereas NCS's method attempted to avoid byte-swap whenever two peers shared a common endianness in their machine-architectures. An industry-group called the Network Computing Forum formed (March 1987) in an (ultimately unsuccessful) attempt to reconcile the two network-computing environments. In 1987, Sun and AT&T announced they would jointly develop AT&T's UNIX System V Release 4. This caused many of AT&T's other licensees of UNIX System to become concerned that this would put Sun in an advantaged position, and ultimately led to Digital Equipment, HP, IBM, and others forming

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4680-498: The consumer market is perhaps the mobile device market, with Android being the dominant operating system on smartphones and very popular on tablets and, more recently, on wearables . Linux gaming is also on the rise with Valve showing its support for Linux and rolling out SteamOS , its own gaming-oriented Linux distribution, which was later implemented in their Steam Deck platform. Linux distributions have also gained popularity with various local and national governments, such as

4770-481: The context dependent symbolic link (CDSL) feature, inspired by HP's TruCluster system, to allow access to node-specific files in a manner transparent to non cluster-aware applications . A CDSL may point to different files on each node in the cluster. CFS, the OpenSSI Cluster File System provides transparent inter-node access to an underlying real file system on one node. CFS is stacked on top of

4860-464: The design of Unix served as a scaffolding, "Linux grew with a lot of mutations – and because the mutations were less than random, they were faster and more directed than alpha-particles in DNA ." Eric S. Raymond considers Linux's revolutionary aspects to be social, not technical: before Linux, complex software was designed carefully by small groups, but "Linux evolved in a completely different way. From nearly

4950-502: The development of 386BSD , from which NetBSD , OpenBSD and FreeBSD descended, predated that of Linux. Linus Torvalds has stated on separate occasions that if the GNU kernel or 386BSD had been available at the time (1991), he probably would not have created Linux. While attending the University of Helsinki in the fall of 1990, Torvalds enrolled in a Unix course. The course used a MicroVAX minicomputer running Ultrix , and one of

5040-527: The development of the Linux kernel on Minix and applications written for Minix were also used on Linux. Later, Linux matured and further Linux kernel development took place on Linux systems. GNU applications also replaced all Minix components, because it was advantageous to use the freely available code from the GNU Project with the fledgling operating system; code licensed under the GNU GPL can be reused in other computer programs as long as they also are released under

5130-476: The development of the components of the system and free software. An analysis of the Linux kernel in 2017 showed that well over 85% of the code was developed by programmers who are being paid for their work, leaving about 8.2% to unpaid developers and 4.1% unclassified. Some of the major corporations that provide contributions include Intel , Samsung , Google , AMD , Oracle , and Facebook . Several corporations, notably Red Hat, Canonical , and SUSE have built

5220-581: The early 1980s, when the LOCUS distributed operating system was developed at UCLA . The group that created ″LOCUS″ went on to form the Locus Computing Corporation in 1982, and produced versions of the technology derived from it under several names. In the mid-1990s, this work culminated in the UnixWare NonStop Clusters product at Tandem Computers , which by 1995 took over the team of

5310-546: The federal government of Brazil . Linus Torvalds is the lead maintainer for the Linux kernel and guides its development, while Greg Kroah-Hartman is the lead maintainer for the stable branch. Zoë Kooyman is the executive director of the Free Software Foundation, which in turn supports the GNU components. Finally, individuals and corporations develop third-party non-GNU components. These third-party components comprise

5400-412: The file system crashes then the CFS mount fails over to the other node that is directly connected to the disk and the cluster now accesses the file system via that node. OpenSSI can use SAN based clustered file systems for its root provided they provide a POSIX compatible file system interface. Lustre and Global File System have been tested, too. With a clustered file system, each node mounts

5490-406: The file system in parallel and access to the files goes directly from the node to the file system. OpenSSI mounts NFS files systems in parallel on each node. Every node accesses the NFS server directly. OpenSSI provides cluster-wide access to all I/O devices on the system, with some limitations - it is not possible for a node to mount a block device from another node. The udev device manager

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5580-421: The file the token is stolen and the cache contents are copied to the stealing node. The OpenSSI CFS implementation is remarkably similar to that used by HP TruCluster . CFS is also used to co-ordinate access to shared memory segments. CFS can be used in a fault tolerant system by using shared disk subsystems (dual ported SCSI or SAN ), or by using DRBD . If the node that is currently directly accessing

5670-654: The first 2 GB of a file to be read due to 32-bit limitations. Version 3 (RFC 1813, June 1995) added: The first NFS Version 3 proposal within Sun Microsystems was created not long after the release of NFS Version 2. The principal motivation was an attempt to mitigate the performance issue of the synchronous write operation in NFS Version ;2. By July 1992, implementation practice had solved many shortcomings of NFS Version 2, leaving only lack of large file support (64-bit file sizes and offsets)

5760-466: The first version of the Linux kernel on the Internet . Like GNU and 386BSD, Linux did not have any Unix code and therefore avoided any current legal issues . Desktop Linux distributions include a windowing system such as X11 or Wayland and a desktop environment such as GNOME , KDE Plasma or Xfce . Distributions intended for servers may not have a graphical user interface at all or include

5850-608: The former Locus CC and rights to the technology. Compaq would purchase Tandem Computers in 1997. The NonStop Clusters were commercialized by Santa Cruz Operation as an add-on for UnixWare. When SCO Group stopped selling the product, the developers (brought in by the Tandem acquisition and now working at Compaq) ported the ″NonStop Clusters″ code to Linux and in 2001, now called OpenSSI , released it as open source. Employees continued development for some time after Compaq being acquired by Hewlett-Packard (which happened in 2002). Over

5940-410: The least loaded node available. OpenSSI is designed to be used for both high performance and high availability clusters. It is possible to create an OpenSSI cluster with no single point of failure , for example the file system can be mirrored between two nodes, so if one node crashes the process accessing the file will fail over to the other node. Alternatively the cluster can be designed in such

6030-516: The mid-1990s in the supercomputing community, where organizations such as NASA started to replace their increasingly expensive machines with clusters of inexpensive commodity computers running Linux. Commercial use began when Dell and IBM , followed by Hewlett-Packard , started offering Linux support to escape Microsoft 's monopoly in the desktop operating system market. Today, Linux systems are used throughout computing, from embedded systems to virtually all supercomputers , and have secured

6120-403: The next decade OpenSSI was enhanced by independent contributors. Linux This is an accepted version of this page Linux ( / ˈ l ɪ n ʊ k s / , LIN -uuks ) is a family of open-source Unix-like operating systems based on the Linux kernel , an operating system kernel first released on September 17, 1991, by Linus Torvalds . Linux is typically packaged as

6210-441: The notable exception. The GNU C library , an implementation of the C standard library , works as a wrapper for the system calls of the Linux kernel necessary to the kernel-userspace interface, the toolchain is a broad collection of programming tools vital to Linux development (including the compilers used to build the Linux kernel itself), and the coreutils implement many basic Unix tools . The GNU Project also develops Bash ,

6300-501: The operating system to their specific needs. Distributions are maintained by individuals, loose-knit teams, volunteer organizations, and commercial entities. A distribution is responsible for the default configuration of the installed Linux kernel, general system security, and more generally integration of the different software packages into a coherent whole. Distributions typically use a package manager such as apt , yum , zypper , pacman or portage to install, remove, and update all of

6390-456: The primary commercial vendor of DFS and AFS, Transarc , donated most of the AFS source code to the free software community in 2000. The OpenAFS project lives on. In early 2005, IBM announced end of sales for AFS and DFS. In January, 2010, Panasas proposed an NFSv4.1 based on their Parallel NFS (pNFS) technology claiming to improve data-access parallelism capability. The NFSv4.1 protocol defines

6480-465: The protocol. Sun used version 1 only for in-house experimental purposes. When the development team added substantial changes to NFS version 1 and released it outside of Sun, they decided to release the new version as v2, so that version interoperation and RPC version fallback could be tested. Version 2 of the protocol (defined in RFC 1094, March 1989) originally operated only over User Datagram Protocol (UDP). Its designers meant to keep

6570-404: The real file system and co-ordinates access from different nodes using a token mechanism. One node has physical access to the underlying file system and performs all read and write operations. At any one time one node owns a token, representing a part of the underlying file, this implies that that part of the file is in the cache of the owning node. If another node tries to access that part of

6660-455: The required texts was Operating Systems: Design and Implementation by Andrew S. Tanenbaum . This textbook included a copy of Tanenbaum's Minix operating system. It was with this course that Torvalds first became exposed to Unix. In 1991, he became curious about operating systems. Frustrated by the licensing of Minix, which at the time limited it to educational use only, he began to work on his operating system kernel, which eventually became

6750-412: The same or a compatible license. Torvalds initiated a switch from his original license, which prohibited commercial redistribution, to the GNU GPL. Developers worked to integrate GNU components with the Linux kernel, creating a fully functional and free operating system. Linus Torvalds had wanted to call his invention " Freax ", a portmanteau of "free", "freak", and "x" (as an allusion to Unix). During

6840-501: The server side stateless , with locking (for example) implemented outside of the core protocol. People involved in the creation of NFS version 2 include Russel Sandberg , Bob Lyon , Bill Joy , Steve Kleiman , and others. The Virtual File System interface allows a modular implementation, reflected in a simple protocol. By February 1986, implementations were demonstrated for operating systems such as System V release 2, DOS , and VAX/VMS using Eunice . NFSv2 only allows

6930-441: The software licenses explicitly permit redistribution, however, provides a basis for larger-scale projects that collect the software produced by stand-alone projects and make it available all at once in the form of a Linux distribution. Many Linux distributions manage a remote collection of system software and application software packages available for download and installation through a network connection. This allows users to adapt

7020-569: The start of his work on the system, some of the project's makefiles included the name "Freax" for about half a year. Initially, Torvalds considered the name "Linux" but dismissed it as too egotistical. To facilitate development, the files were uploaded to the FTP server ( ftp.funet.fi ) of FUNET in September 1991. Ari Lemmke, Torvalds' coworker at the Helsinki University of Technology (HUT) who

7110-471: The use case of the system. This custom interface is accessed through a client that resides on another system, not necessarily Linux-based. Several types of window managers exist for X11, including tiling , dynamic , stacking , and compositing . Window managers provide means to control the placement and appearance of individual application windows, and interact with the X Window System. Simpler X window managers such as dwm , ratpoison , or i3wm provide

7200-507: The use of larger read and write transfer sizes beyond the 8 KB limit imposed by User Datagram Protocol . WebNFS was an extension to NFSv2 and NFSv3 allowing it to function behind restrictive firewalls without the complexity of Portmap and MOUNT protocols. WebNFS had a fixed TCP/UDP port number (2049), and instead of requiring the client to contact the MOUNT RPC service to determine the initial filehandle of every filesystem, it introduced

7290-598: The user wants, be automatically migrated in order to balance load across the cluster. OpenSSI uses an algorithm developed by the MOSIX project for determining the load on each node. OpenSSI provides a single root for the cluster - from any node the same files and directories are available. OpenSSI uses several mechanisms to provide the single root – CFS (the OpenSSI Cluster File System), SAN cluster filesystems and parallel mounts of network file systems. OpenSSI uses

7380-559: The various distribution-specific support and community forums, such as ones for Ubuntu , Fedora, Arch Linux , Gentoo , etc. Linux distributions host mailing lists ; commonly there will be a specific topic such as usage or development for a given list. There are several technology websites with a Linux focus. Print magazines on Linux often bundle cover disks that carry software or even complete Linux distributions. Although Linux distributions are generally available without charge, several large corporations sell, support, and contribute to

7470-429: The word "Linux" should be pronounced, he included an audio guide with the kernel source code. However, in this recording, he pronounces Linux as /ˈlinʊks/ ( LEEN -uuks ) with a short but close front unrounded vowel , instead of a near-close near-front unrounded vowel as in his newsgroup post. The adoption of Linux in production environments, rather than being used only by hobbyists, started to take off first in

7560-501: Was conceived and implemented in 1969, at AT&T 's Bell Labs , in the United States by Ken Thompson , Dennis Ritchie , Douglas McIlroy , and Joe Ossanna . First released in 1971, Unix was written entirely in assembly language , as was common practice at the time. In 1973, in a key pioneering approach, it was rewritten in the C programming language by Dennis Ritchie (except for some hardware and I/O routines). The availability of

7650-494: Was created by Andrew S. Tanenbaum , a computer science professor, and released in 1987 as a minimal Unix-like operating system targeted at students and others who wanted to learn operating system principles. Although the complete source code of Minix was freely available, the licensing terms prevented it from being free software until the licensing changed in April 2000. Although not released until 1992, due to legal complications ,

7740-510: Was designed by Linus Torvalds , following the lack of a working kernel for GNU , a Unix -compatible operating system made entirely of free software that had been undergoing development since 1983 by Richard Stallman . While a separate working Unix-compatible system called Minix was later released, its license was not entirely free at the time. The first entirely free Unix for personal computers, 386BSD , did not appear until 1992, by which time Torvalds had already built and publicly released

7830-459: Was later originally developed, it represented the first successful commercial attempt at distributing a primarily single-user microcomputer that ran a Unix operating system. With Unix increasingly "locked in" as a proprietary product, the GNU Project , started in 1983 by Richard Stallman , had the goal of creating a "complete Unix-compatible software system" composed entirely of free software . Work began in 1984. Later, in 1985, Stallman started

7920-510: Was one of the volunteer administrators for the FTP server at the time, did not think that "Freax" was a good name, so he named the project "Linux" on the server without consulting Torvalds. Later, however, Torvalds consented to "Linux". According to a newsgroup post by Torvalds, the word "Linux" should be pronounced ( / ˈ l ɪ n ʊ k s / LIN -uuks ) with a short 'i' as in 'print' and 'u' as in 'put'. To further demonstrate how

8010-518: Was released from its obligation not to enter the computer business; freed of that obligation, Bell Labs began selling Unix as a proprietary product, where users were not legally allowed to modify it. Onyx Systems began selling early microcomputer-based Unix workstations in 1980. Later, Sun Microsystems , founded as a spin-off of a student project at Stanford University , also began selling Unix-based desktop workstations in 1982. While Sun workstations did not use commodity PC hardware, for which Linux

8100-423: Was writable it is marked readable. OpenSSI uses LVS to provide fault-tolerant load balanced IP services. Inbound network connections are received by a director node which redirects them to the least loaded server node. (A node may be both a director and server). In the event of director node failure another director node takes over and the system continues to accept inbound connections. The OpenSSI software

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