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127-431: BeOS is a discontinued operating system for personal computers that was developed by Be Inc. It was conceived for the company's BeBox personal computer which was released in 1995. BeOS was designed for multitasking , multithreading , and a graphical user interface . The OS was later sold to OEMs , retail, and directly to users; its last version was released as freeware . Early BeOS releases are for PowerPC . It
254-876: 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
381-514: A command-line interface through Bash , although internally it is not a Unix -derived operating system. Many Unix applications were ported to the BeOS command-line interface. BeOS uses Unicode as the default GUI encoding, and support for input methods such as bidirectional text input was never realized. BeOS is bundled with a unique web browser named NetPositive, the BeMail email client , and
508-472: 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
635-424: 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
762-516: 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,
889-428: A system call to perform a block I/O write operation, then the system call might execute the following instructions: While the writing takes place, the operating system will context switch to other processes as normal. When the device finishes writing, the device will interrupt the currently running process by asserting an interrupt request . The device will also place an integer onto the data bus. Upon accepting
1016-568: A 64-bit file system . BeOS Preview Release (PR1), the first for the general public, was released in mid 1997. It supports AppleTalk , PostScript printing, and Unicode . The price for the Full Pack was $ 49.95. Later that year, Preview Release 2 shipped with support for Macintosh's Hierarchical File System (HFS) , support for 512MB RAM, and improvements to the user interface. Release 3 (R3) shipped in March 1998 (initially $ 69.95, later $ 99.95), as
1143-549: A German company named yellowTAB started developing Zeta based on the BeOS R5.1 codebase and released it commercially. It was later distributed by magnussoft . During development by yellowTAB, the company received criticism from the BeOS community for refusing to discuss its legal position with regard to the BeOS codebase. Access Co. (which bought PalmSource , until then the holder of the intellectual property associated with BeOS) declared that yellowTAB had no right to distribute
1270-470: 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
1397-645: A computer even if they are not compatible with the base operating system. A library operating system (libOS) is one in which the services that a typical operating system provides, such as networking, are provided in the form of libraries and composed with a single application and configuration code to construct a unikernel : a specialized (only the absolute necessary pieces of code are extracted from libraries and bound together ), single address space , machine image that can be deployed to cloud or embedded environments. The operating system code and application code are not executed in separated protection domains (there
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#17327984558261524-447: A consumer and developer preview. Also with R5, Be open sourced elements of the user interface. Be CEO Gassée said in 2001 that he was open to the idea of releasing the entire operating system's source code, but this never materialized. Release 5 raised BeOS's popularity but it remained commercially unsuccessful, and BeOS eventually halted following the introduction of a stripped-down version for Internet appliances , BeIA , which became
1651-585: A development of MULTICS for a single user. Because UNIX's source code was available, it became the basis of other, incompatible operating systems, of which the most successful were AT&T 's System V and the University of California 's Berkeley Software Distribution (BSD). To increase compatibility, the IEEE released the POSIX standard for operating system application programming interfaces (APIs), which
1778-974: 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
1905-484: A large legal settlement was paid. In the twenty-first century, Windows continues to be popular on personal computers but has less market share of servers. UNIX operating systems, especially Linux, are the most popular on enterprise systems and servers but are also used on mobile devices and many other computer systems. On mobile devices, Symbian OS was dominant at first, being usurped by BlackBerry OS (introduced 2002) and iOS for iPhones (from 2007). Later on,
2032-442: A library with no protection between applications, such as eCos . A hypervisor is an operating system that runs a virtual machine . The virtual machine is unaware that it is an application and operates as if it had its own hardware. Virtual machines can be paused, saved, and resumed, making them useful for operating systems research, development, and debugging. They also enhance portability by enabling applications to be run on
2159-447: A malformed machine instruction . However, the most common error conditions are division by zero and accessing an invalid memory address . Users can send messages to the kernel to modify the behavior of a currently running process. For example, in the command-line environment , pressing the interrupt character (usually Control-C ) might terminate the currently running process. To generate software interrupts for x86 CPUs,
2286-436: A modified version of BeOS, and magnussoft was forced to cease distribution of the operating system in 2007. Haiku is a complete open source reimplementation of BeOS. It was originally named OpenBeOS and its first release in 2002 was a community update. Unlike Cosmoe and BlueEyedOS, it is directly compatible with BeOS applications. It is open source software. As of 2024, it was the only BeOS clone still under development, with
2413-455: A particular application's memory is stored, or even whether or not it has been allocated yet. In modern operating systems, memory which is accessed less frequently can be temporarily stored on a disk or other media to make that space available for use by other programs. This is called swapping , as an area of memory can be used by multiple programs, and what that memory area contains can be swapped or exchanged on demand. Virtual memory provides
2540-404: 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
2667-502: 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
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#17327984558262794-503: A program does not interfere with memory already in use by another program. Since programs time share, each program must have independent access to memory. Cooperative memory management, used by many early operating systems, assumes that all programs make voluntary use of the kernel 's memory manager, and do not exceed their allocated memory. This system of memory management is almost never seen any more, since programs often contain bugs which can cause them to exceed their allocated memory. If
2921-408: A program fails, it may cause memory used by one or more other programs to be affected or overwritten. Malicious programs or viruses may purposefully alter another program's memory, or may affect the operation of the operating system itself. With cooperative memory management, it takes only one misbehaved program to crash the system. Memory protection enables the kernel to limit a process' access to
3048-440: A program tries to access memory that is not accessible memory, but nonetheless has been allocated to it, the kernel is interrupted (see § Memory management ) . This kind of interrupt is typically a page fault . When the kernel detects a page fault it generally adjusts the virtual memory range of the program which triggered it, granting it access to the memory requested. This gives the kernel discretionary power over where
3175-571: A result, a few projects formed to recreate BeOS or its key elements with the eventual goal of then continuing where Be Inc. quit. BeUnited, a BeOS oriented community, converted itself into a nonprofit organization in August 2001 to "define and promote open specifications for the delivery of the Open Standards BeOS-compatible Operating System (OSBOS) platform". Immediately after Palm's purchase of Be,
3302-470: A significant amount of CPU time. Direct memory access (DMA) is an architecture feature to allow devices to bypass the CPU and access main memory directly. (Separate from the architecture, a device may perform direct memory access to and from main memory either directly or via a bus.) When a computer user types a key on the keyboard, typically the character appears immediately on the screen. Likewise, when
3429-481: 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
3556-493: 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
3683-402: A specific moment in time. Hard real-time systems require exact timing and are common in manufacturing , avionics , military, and other similar uses. With soft real-time systems, the occasional missed event is acceptable; this category often includes audio or multimedia systems, as well as smartphones. In order for hard real-time systems be sufficiently exact in their timing, often they are just
3810-972: 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
3937-402: 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
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4064-417: A user moves a mouse , the cursor immediately moves across the screen. Each keystroke and mouse movement generates an interrupt called Interrupt-driven I/O . An interrupt-driven I/O occurs when a process causes an interrupt for every character or word transmitted. Devices such as hard disk drives , solid-state drives , and magnetic tape drives can transfer data at a rate high enough that interrupting
4191-453: A variation of the classic reader/writer problem . The writer receives a pipe from the shell for its output to be sent to the reader's input stream. The command-line syntax is alpha | bravo . alpha will write to the pipe when its computation is ready and then sleep in the wait queue. bravo will then be moved to the ready queue and soon will read from its input stream. The kernel will generate software interrupts to coordinate
4318-453: 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
4445-418: Is interrupted by it. Operating systems are found on many devices that contain a computer – from cellular phones and video game consoles to web servers and supercomputers . In the personal computer market, as of September 2024 , Microsoft Windows holds a dominant market share of around 73%. macOS by Apple Inc. is in second place (15%), Linux is in third place (5%), and ChromeOS
4572-588: Is object oriented . The user interface was largely multithreaded: each window ran in its own thread, relying heavily on sending messages to communicate between threads; and these concepts are reflected into the API. BeOS uses modern hardware facilities such as modular I/O bandwidth, a multithreaded graphics engine (with the OpenGL library), and a 64-bit journaling file system named BFS supporting files up to one terabyte each. BeOS has partial POSIX compatibility and
4699-562: Is remote direct memory access , which enables each CPU to access memory belonging to other CPUs. Multicomputer operating systems often support remote procedure calls where a CPU can call a procedure on another CPU, or distributed shared memory , in which the operating system uses virtualization to generate shared memory that does not physically exist. A distributed system is a group of distinct, networked computers—each of which might have their own operating system and file system. Unlike multicomputers, they may be dispersed anywhere in
4826-484: Is a change away from the currently running process. Similarly, both hardware and software interrupts execute an interrupt service routine . Software interrupts may be normally occurring events. It is expected that a time slice will occur, so the kernel will have to perform a context switch . A computer program may set a timer to go off after a few seconds in case too much data causes an algorithm to take too long. Software interrupts may be error conditions, such as
4953-422: Is difficult to define, but has been called "the layer of software that manages a computer's resources for its users and their applications ". Operating systems include the software that is always running, called a kernel —but can include other software as well. The two other types of programs that can run on a computer are system programs —which are associated with the operating system, but may not be part of
5080-896: Is in fourth place (2%). In the mobile sector (including smartphones and tablets ), as of September 2023 , Android's share is 68.92%, followed by Apple's iOS and iPadOS with 30.42%, and other operating systems with .66%. Linux distributions are dominant in the server and supercomputing sectors. Other specialized classes of operating systems (special-purpose operating systems), such as embedded and real-time systems, exist for many applications. Security-focused operating systems also exist. Some operating systems have low system requirements (e.g. light-weight Linux distribution ). Others may have higher system requirements. Some operating systems require installation or may come pre-installed with purchased computers ( OEM -installation), whereas others may run directly from media (i.e. live CD ) or flash memory (i.e. USB stick). An operating system
5207-569: 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
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5334-443: Is only a single application running, at least conceptually, so there is no need to prevent interference between applications) and OS services are accessed via simple library calls (potentially inlining them based on compiler thresholds), without the usual overhead of context switches , in a way similarly to embedded and real-time OSes. Note that this overhead is not negligible: to the direct cost of mode switching it's necessary to add
5461-499: Is supported by most UNIX systems. MINIX was a stripped-down version of UNIX, developed in 1987 for educational uses, that inspired the commercially available, free software Linux . Since 2008, MINIX is used in controllers of most Intel microchips , while Linux is widespread in data centers and Android smartphones. The invention of large scale integration enabled the production of personal computers (initially called microcomputers ) from around 1980. For around five years,
5588-403: 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,
5715-473: Is that they do not load user-installed software. Consequently, they do not need protection between different applications, enabling simpler designs. Very small operating systems might run in less than 10 kilobytes , and the smallest are for smart cards . Examples include Embedded Linux , QNX , VxWorks , and the extra-small systems RIOT and TinyOS . A real-time operating system is an operating system that guarantees to process events or data by or at
5842-594: 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
5969-435: Is the part of the operating system that provides protection between different applications and users. This protection is key to improving reliability by keeping errors isolated to one program, as well as security by limiting the power of malicious software and protecting private data, and ensuring that one program cannot monopolize the computer's resources. Most operating systems have two modes of operation: in user mode ,
6096-475: 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
6223-415: 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
6350-542: The CP/M (Control Program for Microcomputers) was the most popular operating system for microcomputers. Later, IBM bought the DOS (Disk Operating System) from Microsoft . After modifications requested by IBM, the resulting system was called MS-DOS (MicroSoft Disk Operating System) and was widely used on IBM microcomputers. Later versions increased their sophistication, in part by borrowing features from UNIX. Apple 's Macintosh
6477-421: 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
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#17327984558266604-761: 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
6731-473: 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
6858-504: The INT assembly language instruction is available. The syntax is INT X , where X is the offset number (in hexadecimal format) to the interrupt vector table . To generate software interrupts in Unix-like operating systems, the kill(pid,signum) system call will send a signal to another process. pid is the process identifier of the receiving process. signum is
6985-476: 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
7112-420: The transistor in the mid-1950s, mainframes began to be built. These still needed professional operators who manually do what a modern operating system would do, such as scheduling programs to run, but mainframes still had rudimentary operating systems such as Fortran Monitor System (FMS) and IBSYS . In the 1960s, IBM introduced the first series of intercompatible computers ( System/360 ). All of them ran
7239-399: 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
7366-454: 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
7493-410: The CPU for every byte or word transferred, and having the CPU transfer the byte or word between the device and memory, would require too much CPU time. Data is, instead, transferred between the device and memory independently of the CPU by hardware such as a channel or a direct memory access controller; an interrupt is delivered only when all the data is transferred. If a computer program executes
7620-474: The CPU to re-enter supervisor mode , placing the kernel in charge. This is called a segmentation violation or Seg-V for short, and since it is both difficult to assign a meaningful result to such an operation, and because it is usually a sign of a misbehaving program, the kernel generally resorts to terminating the offending program, and reports the error. Windows versions 3.1 through ME had some level of memory protection, but programs could easily circumvent
7747-647: The Edirol DV-7 video editors from Roland Corporation , which run on a modified BeOS and the Tunetracker Radio Automation software that used to run it on BeOS and Zeta , and it was also sold as a "Station-in-a-Box" with the Zeta operating system included. In 2015, Tunetracker released a Haiku distribution bundled with its broadcasting software. The Tascam SX-1 digital audio recorder runs a heavily modified version of BeOS that will only launch
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#17327984558267874-674: 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
8001-464: 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
8128-650: 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
8255-562: 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
8382-611: The PoorMan web server . Be operated the marketplace site BeDepot for the purchase and downloading of software including third party, and a website named BeWare listing apps for the platform. Some third party BeOS apps include the Gobe Productive office suite, the Mozilla project, and multimedia apps like Cinema 4D . Quake and Quake II were officially ported, and SimCity 3000 was in development. Be did not disclose
8509-538: The application program, which then interacts with the user and with hardware devices. However, in some systems an application can request that the operating system execute another application within the same process, either as a subroutine or in a separate thread, e.g., the LINK and ATTACH facilities of OS/360 and successors . An interrupt (also known as an abort , exception , fault , signal , or trap ) provides an efficient way for most operating systems to react to
8636-471: 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
8763-512: The company's business focus in place of BeOS. R5 is the final official release of BeOS as Be Inc. became defunct in 2001 following its sale to Palm Inc. BeOS R5.1 "Dano", which was under development before Be's sale to Palm and includes the BeOS Networking Environment (BONE) networking stack, was leaked to the public shortly after the company's close. (Advanced Access Preview Release) Personal Edition/Pro Edition After
8890-447: 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
9017-453: The computer's memory. Various methods of memory protection exist, including memory segmentation and paging . All methods require some level of hardware support (such as the 80286 MMU), which does not exist in all computers. In both segmentation and paging, certain protected mode registers specify to the CPU what memory address it should allow a running program to access. Attempts to access other addresses trigger an interrupt, which causes
9144-498: 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
9271-467: 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
9398-471: The details of how interrupt service routines behave vary from operating system to operating system. However, several interrupt functions are common. The architecture and operating system must: A software interrupt is a message to a process that an event has occurred. This contrasts with a hardware interrupt — which is a message to the central processing unit (CPU) that an event has occurred. Software interrupts are similar to hardware interrupts — there
9525-450: 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
9652-532: 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
9779-476: 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
9906-663: The discontinuation of the BeBox in January 1997, Power Computing began bundling BeOS (on a CD-ROM for optional installation) with its line of PowerPC-based Macintosh clones . These systems can dual boot either Mac OS or BeOS, with a start-up screen offering the choice. Motorola also announced in February 1997 that it would bundle BeOS with their Macintosh clones, the Motorola StarMax , along with MacOS. DayStar Digital
10033-422: The environment. Interrupts cause the central processing unit (CPU) to have a control flow change away from the currently running program to an interrupt handler , also known as an interrupt service routine (ISR). An interrupt service routine may cause the central processing unit (CPU) to have a context switch . The details of how a computer processes an interrupt vary from architecture to architecture, and
10160-559: 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
10287-557: The fifth beta in September 2024 still keeping BeOS 5 compatibility in its x86 32-bit images, with an increased number of ported modern drivers and GTK apps. BlueEyedOS tried to create a system under LGPL based on the Linux kernel and an X server that is compatible with BeOS. Work began under the name BlueOS in 2001 and a demo CD was released in 2003. The project was discontinued in February 2005. Cosmoe, with an interface like BeOS,
10414-604: The first to be ported to the Intel x86 platform in addition to PowerPC, and the first commercially available version of BeOS. The adoption of x86 was partly due to Apple's moves, with Steve Jobs stopping the Macintosh clone market, and Be's mounting debt. BeOS Release 4 had a claimed performance improvement of up to 30 percent. Keyboard shortcuts were changed to mimic those of Windows. However it still lacked Novell NetWare support. It also brought additional drivers and support for
10541-471: 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
10668-410: The hardware checks that the software is only executing legal instructions, whereas the kernel has unrestricted powers and is not subject to these checks. The kernel also manages memory for other processes and controls access to input/output devices. The operating system provides an interface between an application program and the computer hardware, so that an application program can interact with
10795-493: The hardware only by obeying rules and procedures programmed into the operating system. The operating system is also a set of services which simplify development and execution of application programs. Executing an application program typically involves the creation of a process by the operating system kernel , which assigns memory space and other resources, establishes a priority for the process in multi-tasking systems, loads program binary code into memory, and initiates execution of
10922-457: The hope that Apple would purchase or license BeOS as a replacement for its aging Mac OS . The first version of BeOS shipped with the BeBox to a limited number of developers in October 1995. It supported analog and digital audio and MIDI streams, multiple video sources, and 3D computation. Developer Release 6 (DR6) was the first officially available version. The BeOS Developer Release 7 (DR7)
11049-418: The indirect pollution of important processor structures (like CPU caches , the instruction pipeline , and so on) which affects both user-mode and kernel-mode performance. The first computers in the late 1940s and 1950s were directly programmed either with plugboards or with machine code inputted on media such as punch cards , without programming languages or operating systems. After the introduction of
11176-404: The interrupt request, the operating system will: When the writing process has its time slice expired, the operating system will: With the program counter now reset, the interrupted process will resume its time slice. Among other things, a multiprogramming operating system kernel must be responsible for managing all system memory which is currently in use by the programs. This ensures that
11303-431: The kernel—and applications—all other software. There are three main purposes that an operating system fulfills: With multiprocessors multiple CPUs share memory. A multicomputer or cluster computer has multiple CPUs, each of which has its own memory . Multicomputers were developed because large multiprocessors are difficult to engineer and prohibitively expensive; they are universal in cloud computing because of
11430-400: The memory allocated to a different one. Around the same time, teleprinters began to be used as terminals so multiple users could access the computer simultaneously. The operating system MULTICS was intended to allow hundreds of users to access a large computer. Despite its limited adoption, it can be considered the precursor to cloud computing . The UNIX operating system originated as
11557-516: 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
11684-464: The most common SCSI controllers on the x86 platform - from Adaptec and Symbios Logic. The bootloader switched from LILO to Be's own bootman. In 2000, BeOS Release 5 (R5) was released. This was split between a Pro Edition, and a free version known as Personal Edition (BeOS PE) which was released for free online and by CD-ROM. BeOS PE could be booted from within Windows or Linux , and was intended as
11811-408: The need to use it. A general protection fault would be produced, indicating a segmentation violation had occurred; however, the system would often crash anyway. The use of virtual memory addressing (such as paging or segmentation) means that the kernel can choose what memory each program may use at any given time, allowing the operating system to use the same memory locations for multiple tasks. If
11938-441: 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 ,
12065-504: The number of BeOS users, but it was estimated to be running on between 50,000 and 100,000 computers in 1999, and Release 5 reportedly had over one million downloads. For a time it was viewed as a viable competitor to Mac OS and Windows , but its status as the "alternative operating system" was quickly surpassed by Linux by 1998. Reception of the operating system was largely positive citing its true and "reliable" multitasking and support for multiple processors. Though its market penetration
12192-408: The open-source Android operating system (introduced 2008), with a Linux kernel and a C library ( Bionic ) partially based on BSD code, became most popular. The components of an operating system are designed to ensure that various parts of a computer function cohesively. With the de facto obsoletion of DOS , all user software must interact with the operating system to access hardware. The kernel
12319-501: 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
12446-421: The piping. Signals may be classified into 7 categories. The categories are: Input/output (I/O) devices are slower than the CPU. Therefore, it would slow down the computer if the CPU had to wait for each I/O to finish. Instead, a computer may implement interrupts for I/O completion, avoiding the need for polling or busy waiting. Some computers require an interrupt for each character or word, costing
12573-420: The programmer or the user with the perception that there is a much larger amount of RAM in the computer than is really there. Linux 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
12700-431: The recording interface software. The RADAR 24, RADAR V and RADAR 6 , hard disk-based, 24-track professional audio recorders from iZ Technology Corporation were based on BeOS 5. Magicbox, a manufacturer of signage and broadcast display machines, uses BeOS to power their Aavelin product line. Final Scratch , a 12-inch vinyl timecode record-driven DJ software and hardware system, was first developed on BeOS. The "ProFS" version
12827-455: 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
12954-418: The same operating system— OS/360 —which consisted of millions of lines of assembly language that had thousands of bugs . The OS/360 also was the first popular operating system to support multiprogramming , such that the CPU could be put to use on one job while another was waiting on input/output (I/O). Holding multiple jobs in memory necessitated memory partitioning and safeguards against one job accessing
13081-412: 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
13208-400: The signal number (in mnemonic format) to be sent. (The abrasive name of kill was chosen because early implementations only terminated the process.) In Unix-like operating systems, signals inform processes of the occurrence of asynchronous events. To communicate asynchronously, interrupts are required. One reason a process needs to asynchronously communicate to another process solves
13335-400: The size of the machine needed. The different CPUs often need to send and receive messages to each other; to ensure good performance, the operating systems for these machines need to minimize this copying of packets . Newer systems are often multiqueue —separating groups of users into separate queues —to reduce the need for packet copying and support more concurrent users. Another technique
13462-441: 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
13589-529: 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
13716-442: The system and may also include accounting software for cost allocation of processor time , mass storage , peripherals, and other resources. For hardware functions such as input and output and memory allocation , the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or
13843-405: The underlying philosophy of building a "media OS" capable of up-and-coming digital media and multi-processors. Development began in the early 1990s, initially designed to run on AT&T Hobbit -based hardware before being modified to run on PowerPC -based processors: first Be's own BeBox system, and later Apple Computer's PowerPC Reference Platform and Common Hardware Reference Platform , with
13970-471: 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
14097-559: 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
14224-429: 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
14351-473: The world. Middleware , an additional software layer between the operating system and applications, is often used to improve consistency. Although it functions similarly to an operating system, it is not a true operating system. Embedded operating systems are designed to be used in embedded computer systems , whether they are internet of things objects or not connected to a network. Embedded systems include many household appliances. The distinguishing factor
14478-889: Was another licensee. BeOS is compatible with many Macintosh models, but not PowerBook . With BeOS Release 3 on the x86 platform, the operating system is compatible with most computers that run Windows. Hitachi is the first major x86 OEM to ship BeOS, selling the Hitachi Flora Prius line in Japan, and Fujitsu released the Silverline computers in Germany and the Nordic countries. Be was unable to attract further manufacturers due to their Microsoft contracts. Be closed in 2002, and sued Microsoft, claiming that Hitachi had been dissuaded from selling PCs loaded with BeOS. The case
14605-508: 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
14732-498: 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 ,
14859-510: 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
14986-534: Was designed by Bill Hayden as an open source operating system based on the source code of AtheOS , but using the Linux kernel . ZevenOS was designed to continue where Cosmoe left off. BeFree started in 2003, initially developed under FreeBSD and later Linux . Operating system An operating system ( OS ) is system software that manages computer hardware and software resources, and provides common services for computer programs . Time-sharing operating systems schedule tasks for efficient use of
15113-476: Was eventually settled out of court for $ 23.25 million with no admission of liability on Microsoft's part. BeOS was developed as an original product, with a proprietary kernel , symmetric multiprocessing , preemptive multitasking , and pervasive multithreading . It runs in protected memory mode, with a C++ application framework based on shared libraries and modular code. Be initially offered CodeWarrior for application development, and later EGCS . Its API
15240-459: 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
15367-401: Was low, it gained a niche multimedia userbase and acceptance by the audio community. Consequently, it was styled as a "media OS" due to its well-regarded ability to handle audio and video. BeOS received significant interest in Japan, and was also appealing to Amiga developers and users, who were looking for a newer platform. BeOS and its successors have been used in media appliances, such as
15494-513: 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
15621-425: Was ported to Macintosh and then x86 . Be was ultimately unable to achieve a significant market share and ended development with dwindling finances, so Palm acquired the BeOS assets in 2001. Enthusiasts have since created derivate operating systems including Haiku , which will retain BeOS 5 compatibility as of Release R1. BeOS is the product of Apple Computer 's former business executive Jean-Louis Gassée , with
15748-518: 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
15875-619: Was released in April 1996. This includes full 32-bit color graphics, "workspaces" ( virtual desktops ), an FTP file server, and a web server . DR8 was released in September 1996 with a new browser with MPEG and QuickTime video formats. It supports OpenGL , remote access , and Power Macintosh . In 1996, Apple Computer CEO Gil Amelio started negotiations to buy Be Inc., but stalled when Be CEO Jean-Louis Gassée wanted $ 300 million and Apple offered $ 125 million. Apple's board of directors preferred NeXTSTEP and purchased Steve Jobs 's NeXT instead. The final developer's release introduced
16002-402: Was sold to a few dozen DJs prior to the 1.0 release, which ran on a Linux virtual partition. After BeOS came to an end, Palm created PalmSource which used parts of BeOS's multimedia framework for its failed Palm OS Cobalt product (with the takeover of PalmSource, the BeOS rights were assigned to Access Co. ). However, Palm refused the request of BeOS users to license the operating system. As
16129-406: Was the first popular computer to use a graphical user interface (GUI). The GUI proved much more user friendly than the text-only command-line interface earlier operating systems had used. Following the success of Macintosh, MS-DOS was updated with a GUI overlay called Windows . Windows later was rewritten as a stand-alone operating system, borrowing so many features from another ( VAX VMS ) that
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