An operating system 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 the system and may include accounting software for cost allocation of processor time, mass storage 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 executed directly by the hardware and makes system calls to an OS function or 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; the dominant desktop operating system is Microsoft Windows with a market share of around 82.74%. MacOS by Apple Inc. is in second place, the varieties of Linux are collectively in third place. In the mobile sector, use in 2017 is up to 70% of Google's Android and according to third quarter 2016 data, Android on smartphones is dominant with 87.5 percent and a growth rate 10.3 percent per year, followed by Apple's iOS with 12.1 percent and a per year decrease in market share of 5.2 percent, while other operating systems amount to just 0.3 percent.
Linux distributions are dominant in supercomputing sectors. Other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can only run one program at a time, while a multi-tasking operating system allows more than one program to be running in concurrency; this is achieved by time-sharing, where the available processor time is divided between multiple processes. These processes are each interrupted in time slices by a task-scheduling subsystem of the operating system. Multi-tasking may be characterized in co-operative types. In preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, such as Solaris and Linux—as well as non-Unix-like, such as AmigaOS—support preemptive multitasking. Cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking.
32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem. A multi-user operating system extends the basic concept of multi-tasking with facilities that identify processes and resources, such as disk space, belonging to multiple users, the system permits multiple users to interact with the system at the same time. Time-sharing operating systems schedule tasks for efficient use of the system and may include accounting software for cost allocation of processor time, mass storage and other resources to multiple users. A distributed operating system manages a group of distinct computers and makes them appear to be a single computer; the development of networked computers that could be linked and communicate with each other gave rise to distributed computing. Distributed computations are carried out on more than one machine; when computers in a group work in cooperation, they form a distributed system.
In an OS, distributed and cloud computing context, templating refers to creating a single virtual machine image as a guest operating system saving it as a tool for multiple running virtual machines. The technique is used both in virtualization and cloud computing management, is common in large server warehouses. Embedded operating systems are designed to be used in embedded computer systems, they are designed to operate on small machines like PDAs with less autonomy. They are able to operate with a limited number of resources, they are compact and efficient by design. Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is an operating system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, it uses specialized scheduling algorithms so that a deterministic nature of behavior is achieved. An event-driven system switches between tasks based on their priorities or external events while time-sharing operating systems switch tasks based on clock interrupts.
A library operating system 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 the application and configuration code to construct a unikernel: a specialized, single address space, machine image that can be deployed to cloud or embedded environments. Early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could automatically run different programs in succession to speed up processing. Operating systems did not exist in their more complex forms until the early 1960s. Hardware features were added, that enabled use of runtime libraries and parallel processing; when personal computers became popular in the 1980s, operating systems were made for them similar in concept to those used on larger computers. In the 1940s, the earliest electronic digital systems had no operating systems.
Electronic systems of this time were programmed on rows of mechanical switches or by jumper wires on plug boards. These were special-purpose systems that, for example, generated ballistics tables for the military or controlled the pri
GitHub is a web-based hosting service for version control using Git. It is used for computer code, it offers all of the distributed version control and source code management functionality of Git as well as adding its own features. It provides access control and several collaboration features such as bug tracking, feature requests, task management, wikis for every project. GitHub offers plans for enterprise, team and free accounts which are used to host open-source software projects; as of January 2019, GitHub offers unlimited private repositories to all plans, including free accounts. As of June 2018, GitHub reports having over 28 million users and 57 million repositories, making it the largest host of source code in the world. GitHub was developed by Chris Wanstrath, P. J. Hyett, Tom Preston-Werner and Scott Chacon using Ruby on Rails, started in February 2008; the company, GitHub, Inc. is located in San Francisco. On February 24, 2009, GitHub team members announced, in a talk at Yahoo! headquarters, that within the first year of being online, GitHub had accumulated over 46,000 public repositories, 17,000 of which were formed in the previous month alone.
At that time, about 6,200 repositories had been forked at least. On July 5, 2009, GitHub announced. On July 27, 2009, in another talk delivered at Yahoo!, Preston-Werner announced that GitHub had grown to host 90,000 unique public repositories, 12,000 having been forked at least once, for a total of 135,000 repositories. On July 25, 2010, GitHub announced. On April 20, 2011, GitHub announced. On June 2, 2011, ReadWriteWeb reported that GitHub had surpassed SourceForge and Google Code in total number of commits for the period of January to May 2011. On July 9, 2012, Peter Levine, general partner at GitHub investor Andreessen Horowitz, stated that GitHub had been growing revenue at 300% annually since 2008 "profitably nearly the entire way". On January 16, 2013, GitHub announced it had passed the 3 million users mark and was hosting more than 5 million repositories. On December 23, 2013, GitHub announced. In June 2015, GitHub opened an office in Japan, its first office outside of the U. S. On July 29, 2015, GitHub announced it had raised $250 million in funding in a round led by Sequoia Capital.
The round valued the company at $2 billion. In 2016, GitHub was ranked No. 14 on the Forbes Cloud 100 list. On February 28, 2018, GitHub fell victim to the second largest distributed denial-of-service attack in history, with incoming traffic reaching a peak of about 1.35 terabits per second. On June 4, 2018, Microsoft announced it had reached an agreement to acquire GitHub for US$7.5 billion. The purchase closed on October 26, 2018. On June 19, 2018, GitHub expanded its GitHub Education by offering free education bundles to all schools. On June 4, 2018, Microsoft announced its intent to acquire GitHub for US$7.5 billion, the deal closed on Oct. 26, 2018. GitHub will continue to operate independently as a community and business. Under Microsoft, the service will be led by Xamarin's Nat Friedman, reporting to Scott Guthrie, executive vice president of Microsoft Cloud and AI. Current CEO Chris Wanstrath will be retained as a "technical fellow" reporting to Guthrie. Microsoft had become a significant user of GitHub, using it to host open source projects and development tools such as Chakra Core, PowerShell, Visual Studio Code, has backed other open source projects such as Linux, developed Git Virtual File System—a Git extension for managing large-scale repositories.
GitHub, Inc. was a flat organization with no middle managers. Employees can choose to work on projects. However, salaries are set by the chief executive. In 2014, GitHub, Inc. introduced a layer of middle management. GitHub.com was a start-up business, which in its first years provided enough revenue to be funded by its three founders and start taking on employees. In July 2012, four years after the company was founded, Andreessen Horowitz invested $100 million in venture capital. In July 2015 GitHub raised another $250 million of venture capital in a series B round. Investors were Andreessen Horowitz, Thrive Capital and other venture capital funds; as of August 2016, GitHub was making $140 million in Annual Recurring Revenue. GitHub's m
MacOS is a series of graphical operating systems developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac family of computers. Within the market of desktop and home computers, by web usage, it is the second most used desktop OS, after Microsoft Windows.macOS is the second major series of Macintosh operating systems. The first is colloquially called the "classic" Mac OS, introduced in 1984, the final release of, Mac OS 9 in 1999; the first desktop version, Mac OS X 10.0, was released in March 2001, with its first update, 10.1, arriving that year. After this, Apple began naming its releases after big cats, which lasted until OS X 10.8 Mountain Lion. Since OS X 10.9 Mavericks, releases have been named after locations in California. Apple shortened the name to "OS X" in 2012 and changed it to "macOS" in 2016, adopting the nomenclature that they were using for their other operating systems, iOS, watchOS, tvOS; the latest version is macOS Mojave, publicly released in September 2018.
Between 1999 and 2009, Apple sold. The initial version, Mac OS X Server 1.0, was released in 1999 with a user interface similar to Mac OS 8.5. After this, new versions were introduced concurrently with the desktop version of Mac OS X. Beginning with Mac OS X 10.7 Lion, the server functions were made available as a separate package on the Mac App Store.macOS is based on technologies developed between 1985 and 1997 at NeXT, a company that Apple co-founder Steve Jobs created after leaving the company. The "X" in Mac OS X and OS X is pronounced as such; the X was a prominent part of the operating system's brand identity and marketing in its early years, but receded in prominence since the release of Snow Leopard in 2009. UNIX 03 certification was achieved for the Intel version of Mac OS X 10.5 Leopard and all releases from Mac OS X 10.6 Snow Leopard up to the current version have UNIX 03 certification. MacOS shares its Unix-based core, named Darwin, many of its frameworks with iOS, tvOS and watchOS.
A modified version of Mac OS X 10.4 Tiger was used for the first-generation Apple TV. Releases of Mac OS X from 1999 to 2005 ran on the PowerPC-based Macs of that period. After Apple announced that they were switching to Intel CPUs from 2006 onwards, versions were released for 32-bit and 64-bit Intel-based Macs. Versions from Mac OS X 10.7 Lion run on 64-bit Intel CPUs, in contrast to the ARM architecture used on iOS and watchOS devices, do not support PowerPC applications. The heritage of what would become macOS had originated at NeXT, a company founded by Steve Jobs following his departure from Apple in 1985. There, the Unix-like NeXTSTEP operating system was developed, launched in 1989; the kernel of NeXTSTEP is based upon the Mach kernel, developed at Carnegie Mellon University, with additional kernel layers and low-level user space code derived from parts of BSD. Its graphical user interface was built on top of an object-oriented GUI toolkit using the Objective-C programming language. Throughout the early 1990s, Apple had tried to create a "next-generation" OS to succeed its classic Mac OS through the Taligent and Gershwin projects, but all of them were abandoned.
This led Apple to purchase NeXT in 1996, allowing NeXTSTEP called OPENSTEP, to serve as the basis for Apple's next generation operating system. This purchase led to Steve Jobs returning to Apple as an interim, the permanent CEO, shepherding the transformation of the programmer-friendly OPENSTEP into a system that would be adopted by Apple's primary market of home users and creative professionals; the project was first code named "Rhapsody" and officially named Mac OS X. Mac OS X was presented as the tenth major version of Apple's operating system for Macintosh computers. Previous Macintosh operating systems were named using Arabic numerals, as with Mac OS 8 and Mac OS 9; the letter "X" in Mac OS X's name refers to a Roman numeral. It is therefore pronounced "ten" in this context. However, it is commonly pronounced like the letter "X"; the first version of Mac OS X, Mac OS X Server 1.0, was a transitional product, featuring an interface resembling the classic Mac OS, though it was not compatible with software designed for the older system.
Consumer releases of Mac OS X included more backward compatibility. Mac OS applications could be rewritten to run natively via the Carbon API; the consumer version of Mac OS X was launched in 2001 with Mac OS X 10.0. Reviews were variable, with extensive praise for its sophisticated, glossy Aqua interface but criticizing it for sluggish performance. With Apple's popularity at a low, the makers of several classic Mac applications such as FrameMaker and PageMaker declined to develop new versions of their software for Mac OS X. Ars Technica columnist John Siracusa, who reviewed every major OS X release up to 10.10, described the early releases in retrospect as'dog-slow, feature poor' and Aqua as'unbearably slow and a huge resource hog'. Apple developed several new releases of Mac OS X. Siracusa's review of version 10.3, noted "It's strange to have gone from years of uncertainty and vaporware to a steady annual supply of major new operating system releases." Version 10.4, Tiger shocked executives at Microsoft by offering a number of features, such as fast file s
NetBSD is a free and open-source Unix-like operating system based on the Berkeley Software Distribution. It was the first open-source BSD descendant released after 386BSD was forked, it continues to be developed and is available for many platforms, including servers, handheld devices, embedded systems. The NetBSD project focuses on code clarity, careful design, portability across many computer architectures, its source code is permissively licensed. NetBSD was derived from the 4.3BSD-Reno release of the Berkeley Software Distribution from the Computer Systems Research Group of the University of California, via their Net/2 source code release and the 386BSD project. The NetBSD project began as a result of frustration within the 386BSD developer community with the pace and direction of the operating system's development; the four founders of the NetBSD project, Chris Demetriou, Theo de Raadt, Adam Glass, Charles Hannum, felt that a more open development model would benefit the project: one centered on portable, correct code.
They aimed to produce a multi-platform, production-quality, BSD-based operating system. The name "NetBSD" was suggested by De Raadt, based on the importance and growth of networks such as the Internet at that time, the distributed, collaborative nature of its development; the NetBSD source code repository was established on 21 March 1993 and the first official release, NetBSD 0.8, was made on 19 April 1993. This was derived from 386BSD 0.1 plus the version 0.2.2 unofficial patchkit, with several programs from the Net/2 release missing from 386BSD re-integrated, various other improvements. The first multi-platform release, NetBSD 1.0, was made in October 1994, being updated with 4.4BSD-Lite sources, it was free of all encumbered 4.3BSD Net/2 code. In 1994, for disputed reasons, one of the founders, Theo de Raadt, was removed from the project, he founded a new project, OpenBSD, from a forked version of NetBSD 1.0 near the end of 1995. In 1998, NetBSD 1.3 introduced the pkgsrc packages collection.
Until 2004, NetBSD 1.x releases were made at annual intervals, with minor "patch" releases in between. From release 2.0 onwards, NetBSD uses semantic versioning, each major NetBSD release corresponds to an incremented major version number, i.e. the major releases following 2.0 are 3.0, 4.0 and so on. The previous minor releases are now divided into two categories: x.y "stable" maintenance releases and x.y.z releases containing only security and critical fixes. As the project's motto suggests, NetBSD has been ported to a large number of 32- and 64-bit architectures; these range from VAX minicomputers to Pocket PC PDAs. As of 2009, NetBSD supports 57 hardware platforms; the kernel and userland for these platforms are all built from a central unified source-code tree managed by CVS. Unlike other kernels such as μClinux, the NetBSD kernel requires the presence of an MMU in any given target architecture. NetBSD's portability is aided by the use of hardware abstraction layer interfaces for low-level hardware access such as bus input/output or DMA.
Using this portability layer, device drivers can be split into "machine-independent" and "machine-dependent" components. This makes a single driver usable on several platforms by hiding hardware access details, reduces the work to port it to a new system; this permits a particular device driver for a PCI card to work without modifications, whether it is in a PCI slot on an IA-32, PowerPC, SPARC, or other architecture with a PCI bus. A single driver for a specific device can operate via several different buses, like ISA, PCI, or PC Card. In comparison, Linux device driver code must be reworked for each new architecture; as a consequence, in porting efforts by NetBSD and Linux developers, NetBSD has taken much less time to port to new hardware. This platform independence aids the development of embedded systems since NetBSD 1.6, when the entire toolchain of compilers, assemblers and other tools support cross-compiling. In 2005, as a demonstration of NetBSD's portability and suitability for embedded applications, Technologic Systems, a vendor of embedded systems hardware and demonstrated a NetBSD-powered kitchen toaster.
Commercial ports to embedded platforms, including the AMD Geode LX800, Freescale PowerQUICC processors, Marvell Orion, AMCC 405 family of PowerPC processors, Intel XScale IOP and IXP series, were available from and supported by Wasabi Systems. The NetBSD cross-compiling framework lets a developer build a complete NetBSD system for an architecture from a more powerful system of different architecture, including on a different operating system. Several embedded systems using NetBSD have required no additional software development other than toolchain and target rehost. NetBSD features pkgsrc, a framework for building and managing third-party application software packages; the pkgsrc collection consists of more than 18,000 packages as of April 2018. Building and installing packages such as KDE, GNOME, the Apache HTTP Server or Perl is performed through the use of a system of makefiles; this can automatically fetch the source code, patch, configure and install the package such that it can be removed again later.
An alternative to compiling from source is to use a precompiled binary package. In either case, any prerequisites/dependencies will be installed automatically by the package system, without need for manual intervention. Pkgsrc supports not only NetBSD, but several other BSD variants like
A timer is a specialized type of clock used for measuring specific time intervals. Timers can be categorized into two main types. A timer which counts upwards from zero for measuring elapsed time is called a stopwatch, while a device which counts down from a specified time interval is more called a timer. A simple example of this type is an hourglass. Working method timers have two main groups: Hardware and Software timers. Most timers give an indication that the time interval, set has expired. Time switches, timing mechanisms which activate a switch, are sometimes called "timers". Mechanical timers use clockwork to measure time. Manual timers are set by turning a dial to the time interval desired, they function to a mechanical alarm clock. Each swing of the wheel releases the gear train to move forward by a small fixed amount, causing the dial to move backward until it reaches zero when a lever arm strikes a bell; the mechanical kitchen timer was invented in 1926 by Thomas Norman Hicks. Some less accurate, cheaper mechanisms use a flat paddle called a fan fly that spins against air resistance.
The simplest and oldest type of mechanical timer is the hourglass, in which a fixed amount of sand drains through a narrow opening from one chamber to another to measure a time interval. Short-period bimetallic electromechanical timers use a thermal mechanism, with a metal finger made of strips of two metals with different rates of thermal expansion sandwiched together. An electric current flowing through this finger causes heating of the metals, one side expands less than the other, an electrical contact on the end of the finger moves away from or towards an electrical switch contact; the most common use of this type is in the "flasher" units that flash turn signals in automobiles, sometimes in Christmas lights. This is a non-electronic type of multivibrator. An electromechanical cam timer uses a small synchronous AC motor turning a cam against a comb of switch contacts; the AC motor is turned at an accurate rate by the alternating current, which power companies regulate. Gears drive a shaft at the desired rate, turn the cam.
The most common application of this timer now is in washers and dishwashers. This type of timer has a friction clutch between the gear train and the cam, so that the cam can be turned to reset the time. Electromechanical timers survive in these applications because mechanical switch contacts may still be less expensive than the semiconductor devices needed to control powerful lights and heaters. In the past, these electromechanical timers were combined with electrical relays to create electro-mechanical controllers. Electromechanical timers reached a high state of development in the 1950s and 1960s because of their extensive use in aerospace and weapons systems. Programmable electromechanical timers controlled launch sequence events in early rockets and ballistic missiles; as digital electronics has progressed and dropped in price, electronic timers have become more advantageous. Electronic timers are quartz clocks with special electronics, can achieve higher precision than mechanical timers.
Electronic timers may have an analog or digital display. Integrated circuits have made digital logic so inexpensive that an electronic timer is now less expensive than many mechanical and electromechanical timers. Individual timers are implemented as a simple single-chip computer system, similar to a watch and using the same, mass-produced, technology. Many timers are now implemented in software. Modern controllers use a programmable logic controller rather than a box full of electromechanical parts; the logic is designed as if it were relays, using a special computer language called ladder logic. In PLCs, timers are simulated by the software built into the controller; each timer is just an entry in a table maintained by the software. Digital timers are used in safety devices such as a gas timer; these types of timers are not parts of devices. They rely on the accuracy of a clock generator built into a hardware device that runs the software. Nowadays when people are using more and more mobile phones, there are timer apps that mimic the old mechanical timer, but which have highly sophisticated functions.
These apps are easier to use daily, because they are available at once, without any need to purchase or carry the separate devices, as today timer is just a software application on a phone or tablet. Some of these apps are stopwatch timers, etc.. These timer apps can be used for tracking working or training time, motivating children to do tasks, replacing an hour glass in board games, or for the traditional purpose for tracking time when cooking and baking. Apps may be superior to mechanical timers. Hour glasses are not precise and clear, they can jam. Mechanical timers lack the customization that applications support, such as sound volume adjustments for individual needs. Most applications will offer selectable alarm sounds; some timer applications can help children to understand the concept of time, help them to finish tasks in time, help them to get motivated. These applications are used with children with special needs like ADHD, Down syndrome, etc. but everybody else can benefit from them.
Computer systems have at least one hardware timer. These are digital counters that either increm
Computer data storage
Computer data storage called storage or memory, is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers; the central processing unit of a computer is. In practice all computers use a storage hierarchy, which puts fast but expensive and small storage options close to the CPU and slower but larger and cheaper options farther away; the fast volatile technologies are referred to as "memory", while slower persistent technologies are referred to as "storage". In the Von Neumann architecture, the CPU consists of two main parts: The control unit and the arithmetic logic unit; the former controls the flow of data between the CPU and memory, while the latter performs arithmetic and logical operations on data. Without a significant amount of memory, a computer would be able to perform fixed operations and output the result, it would have to be reconfigured to change its behavior. This is acceptable for devices such as desk calculators, digital signal processors, other specialized devices.
Von Neumann machines differ in having a memory in which they store their operating instructions and data. Such computers are more versatile in that they do not need to have their hardware reconfigured for each new program, but can be reprogrammed with new in-memory instructions. Most modern computers are von Neumann machines. A modern digital computer represents data using the binary numeral system. Text, pictures and nearly any other form of information can be converted into a string of bits, or binary digits, each of which has a value of 1 or 0; the most common unit of storage is the byte, equal to 8 bits. A piece of information can be handled by any computer or device whose storage space is large enough to accommodate the binary representation of the piece of information, or data. For example, the complete works of Shakespeare, about 1250 pages in print, can be stored in about five megabytes with one byte per character. Data are encoded by assigning a bit pattern to digit, or multimedia object.
Many standards exist for encoding. By adding bits to each encoded unit, redundancy allows the computer to both detect errors in coded data and correct them based on mathematical algorithms. Errors occur in low probabilities due to random bit value flipping, or "physical bit fatigue", loss of the physical bit in storage of its ability to maintain a distinguishable value, or due to errors in inter or intra-computer communication. A random bit flip is corrected upon detection. A bit, or a group of malfunctioning physical bits is automatically fenced-out, taken out of use by the device, replaced with another functioning equivalent group in the device, where the corrected bit values are restored; the cyclic redundancy check method is used in communications and storage for error detection. A detected error is retried. Data compression methods allow in many cases to represent a string of bits by a shorter bit string and reconstruct the original string when needed; this utilizes less storage for many types of data at the cost of more computation.
Analysis of trade-off between storage cost saving and costs of related computations and possible delays in data availability is done before deciding whether to keep certain data compressed or not. For security reasons certain types of data may be kept encrypted in storage to prevent the possibility of unauthorized information reconstruction from chunks of storage snapshots; the lower a storage is in the hierarchy, the lesser its bandwidth and the greater its access latency is from the CPU. This traditional division of storage to primary, secondary and off-line storage is guided by cost per bit. In contemporary usage, "memory" is semiconductor storage read-write random-access memory DRAM or other forms of fast but temporary storage. "Storage" consists of storage devices and their media not directly accessible by the CPU hard disk drives, optical disc drives, other devices slower than RAM but non-volatile. Memory has been called core memory, main memory, real storage or internal memory. Meanwhile, non-volatile storage devices have been referred to as secondary storage, external memory or auxiliary/peripheral storage.
Primary storage referred to as memory, is the only one directly accessible to the CPU. The CPU continuously reads instructions executes them as required. Any data operated on is stored there in uniform manner. Early computers used delay lines, Williams tubes, or rotating magnetic drums as primary storage. By 1954, those unreliable methods were replaced by magnetic core memory. Core memory remained dominant until the 1970s, when advances in integrated circuit technology allowed semiconductor memory to become economically competitive; this led to modern random-access memo
Solaris (operating system)
Solaris is a Unix operating system developed by Sun Microsystems. It superseded their earlier SunOS in 1993. In 2010, after the Sun acquisition by Oracle, it was renamed Oracle Solaris. Solaris is known for its scalability on SPARC systems, for originating many innovative features such as DTrace, ZFS and Time Slider. Solaris supports SPARC and x86-64 servers from Oracle and other vendors. Solaris is registered as compliant with the Single UNIX Specification. Solaris was developed as proprietary software. In June 2005, Sun Microsystems released most of the codebase under the CDDL license, founded the OpenSolaris open-source project. With OpenSolaris, Sun wanted to build a user community around the software. After the acquisition of Sun Microsystems in January 2010, Oracle decided to discontinue the OpenSolaris distribution and the development model. In August 2010, Oracle discontinued providing public updates to the source code of the Solaris kernel turning Solaris 11 back into a closed source proprietary operating system.
Following that, in 2011 the Solaris 11 kernel source code leaked to BitTorrent. However, through the Oracle Technology Network, industry partners can still gain access to the in-development Solaris source code. Source code for the open source components of Solaris 11 is available for download from Oracle. In 1987, AT&T Corporation and Sun announced that they were collaborating on a project to merge the most popular Unix variants on the market at that time: Berkeley Software Distribution, UNIX System V, Xenix; this became Unix System V Release 4. On September 4, 1991, Sun announced that it would replace its existing BSD-derived Unix, SunOS 4, with one based on SVR4; this was identified internally as SunOS 5, but a new marketing name was introduced at the same time: Solaris 2. The justification for this new overbrand was that it encompassed not only SunOS, but the OpenWindows graphical user interface and Open Network Computing functionality. Although SunOS 4.1.x micro releases were retroactively named Solaris 1 by Sun, the Solaris name is used exclusively to refer only to the releases based on SVR4-derived SunOS 5.0 and later.
For releases based on SunOS 5, the SunOS minor version is included in the Solaris release number. For example, Solaris 2.4 incorporates SunOS 5.4. After Solaris 2.6, the 2. was dropped from the release name, so Solaris 7 incorporates SunOS 5.7, the latest release SunOS 5.11 forms the core of Solaris 11.4. Although SunSoft stated in its initial Solaris 2 press release their intent to support both SPARC and x86 systems, the first two Solaris 2 releases, 2.0 and 2.1, were SPARC-only. An x86 version of Solaris 2.1 was released in June 1993, about 6 months after the SPARC version, as a desktop and uniprocessor workgroup server operating system. It included the Wabi emulator to support Windows applications. At the time, Sun offered the Interactive Unix system that it had acquired from Interactive Systems Corporation. In 1994, Sun released Solaris 2.4, supporting both SPARC and x86 systems from a unified source code base. On September 2, 2017, Simon Phipps, a former Sun Microsystems employee not hired by Oracle in the acquisition, reported on Twitter that Oracle had laid off the Solaris core development staff, which many interpreted as sign that Oracle no longer intended to support future development of the platform.
While Oracle did have a large layoff of Solaris development engineering staff, development continues today of which Solaris 11.4 was released in 2018. Solaris uses a common code base for the platforms it supports: i86pc. Solaris has a reputation for being well-suited to symmetric multiprocessing, supporting a large number of CPUs, it has been integrated with Sun's SPARC hardware, with which it is marketed as a combined package. This has led to more reliable systems, but at a cost premium compared to commodity PC hardware. However, it has supported x86 systems since Solaris 2.1 and 64-bit x86 applications since Solaris 10, allowing Sun to capitalize on the availability of commodity 64-bit CPUs based on the x86-64 architecture. Sun has marketed Solaris for use with both its own "x64" workstations and servers based on AMD Opteron and Intel Xeon processors, as well as x86 systems manufactured by companies such as Dell, Hewlett-Packard, IBM; as of 2009, the following vendors support Solaris for their x86 server systems: Dell – will "test and optimize Solaris and OpenSolaris on its rack and blade servers and offer them as one of several choices in the overall Dell software menu" Intel Hewlett Packard Enterprise – distributes and provides software technical support for Solaris on BL, DL, SL platforms Fujitsu SiemensAs of July 2010, Dell and HP certify and resell Oracle Solaris, Oracle Enterprise Linux and Oracle VM on their respective x86 platforms, IBM stopped direct support for Solaris on x64 kit.
Solaris 2.5.1 included support for the PowerPC platform, but the port was canceled before the Solaris 2.6 release. In January 2006, a community of developers at Blastwave began work on a PowerPC port which they named Polaris. In October 2006, an OpenSolaris community project based on the Blastwave efforts and Sun Labs' Project Pulsar, which re-integrated the relevant parts from Solaris 2.5.1 into OpenSolaris, announced its first official source code release. A port of Solaris to the Intel Itanium architecture was announced in 1997 but never brought to market. On November 28, 2007, IBM, Sine Nomine Associates demonstrated a preview of OpenSolaris for System z running on an IBM System z mainframe under z/VM, called Sirius