Microsoft Windows is a group of several graphical operating system families, all of which are developed and sold by Microsoft. Each family caters to a certain sector of the computing industry. Active Windows families include Windows Embedded. Defunct Windows families include Windows Mobile and Windows Phone. Microsoft introduced an operating environment named Windows on November 20, 1985, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces. Microsoft Windows came to dominate the world's personal computer market with over 90% market share, overtaking Mac OS, introduced in 1984. Apple came to see Windows as an unfair encroachment on their innovation in GUI development as implemented on products such as the Lisa and Macintosh. On PCs, Windows is still the most popular operating system. However, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android, because of the massive growth in sales of Android smartphones.
In 2014, the number of Windows devices sold was less than 25 %. This comparison however may not be relevant, as the two operating systems traditionally target different platforms. Still, numbers for server use of Windows show one third market share, similar to that for end user use; as of October 2018, the most recent version of Windows for PCs, tablets and embedded devices is Windows 10. The most recent versions for server computers is Windows Server 2019. A specialized version of Windows runs on the Xbox One video game console. Microsoft, the developer of Windows, has registered several trademarks, each of which denote a family of Windows operating systems that target a specific sector of the computing industry; as of 2014, the following Windows families are being developed: Windows NT: Started as a family of operating systems with Windows NT 3.1, an operating system for server computers and workstations. It now consists of three operating system subfamilies that are released at the same time and share the same kernel: Windows: The operating system for mainstream personal computers and smartphones.
The latest version is Windows 10. The main competitor of this family is macOS by Apple for personal computers and Android for mobile devices. Windows Server: The operating system for server computers; the latest version is Windows Server 2019. Unlike its client sibling, it has adopted a strong naming scheme; the main competitor of this family is Linux. Windows PE: A lightweight version of its Windows sibling, meant to operate as a live operating system, used for installing Windows on bare-metal computers, recovery or troubleshooting purposes; the latest version is Windows PE 10. Windows IoT: Initially, Microsoft developed Windows CE as a general-purpose operating system for every device, too resource-limited to be called a full-fledged computer. However, Windows CE was renamed Windows Embedded Compact and was folded under Windows Compact trademark which consists of Windows Embedded Industry, Windows Embedded Professional, Windows Embedded Standard, Windows Embedded Handheld and Windows Embedded Automotive.
The following Windows families are no longer being developed: Windows 9x: An operating system that targeted consumers market. Discontinued because of suboptimal performance. Microsoft now caters to the consumer market with Windows NT. Windows Mobile: The predecessor to Windows Phone, it was a mobile phone operating system; the first version was called Pocket PC 2000. The last version is Windows Mobile 6.5. Windows Phone: An operating system sold only to manufacturers of smartphones; the first version was Windows Phone 7, followed by Windows Phone 8, the last version Windows Phone 8.1. It was succeeded by Windows 10 Mobile; the term Windows collectively describes any or all of several generations of Microsoft operating system products. These products are categorized as follows: The history of Windows dates back to 1981, when Microsoft started work on a program called "Interface Manager", it was announced in November 1983 under the name "Windows", but Windows 1.0 was not released until November 1985.
Windows 1.0 was to achieved little popularity. Windows 1.0 is not a complete operating system. The shell of Windows 1.0 is a program known as the MS-DOS Executive. Components included Calculator, Cardfile, Clipboard viewer, Control Panel, Paint, Reversi and Write. Windows 1.0 does not allow overlapping windows. Instead all windows are tiled. Only modal dialog boxes may appear over other windows. Microsoft sold as included Windows Development libraries with the C development environment, which included numerous windows samples. Windows 2.0 was released in December 1987, was more popular than its predecessor. It features several improvements to the user memory management. Windows 2.03 changed the OS from tiled windows to overlapping windows. The result of this change led to Apple Computer filing a suit against Microsoft alleging infringement on Apple's copyrights. Windows 2.0
C++ is a general-purpose programming language, developed by Bjarne Stroustrup as an extension of the C language, or "C with Classes". It has imperative, object-oriented and generic programming features, while providing facilities for low-level memory manipulation, it is always implemented as a compiled language, many vendors provide C++ compilers, including the Free Software Foundation, Intel, IBM, so it is available on many platforms. C++ was designed with a bias toward system programming and embedded, resource-constrained software and large systems, with performance and flexibility of use as its design highlights. C++ has been found useful in many other contexts, with key strengths being software infrastructure and resource-constrained applications, including desktop applications and performance-critical applications. C++ is standardized by the International Organization for Standardization, with the latest standard version ratified and published by ISO in December 2017 as ISO/IEC 14882:2017.
The C++ programming language was standardized in 1998 as ISO/IEC 14882:1998, amended by the C++03, C++11 and C++14 standards. The current C++ 17 standard supersedes these with an enlarged standard library. Before the initial standardization in 1998, C++ was developed by Danish computer scientist Bjarne Stroustrup at Bell Labs since 1979 as an extension of the C language. C++20 is the next planned standard, keeping with the current trend of a new version every three years. In 1979, Bjarne Stroustrup, a Danish computer scientist, began work on "C with Classes", the predecessor to C++; the motivation for creating a new language originated from Stroustrup's experience in programming for his Ph. D. thesis. Stroustrup found that Simula had features that were helpful for large software development, but the language was too slow for practical use, while BCPL was fast but too low-level to be suitable for large software development; when Stroustrup started working in AT&T Bell Labs, he had the problem of analyzing the UNIX kernel with respect to distributed computing.
Remembering his Ph. D. experience, Stroustrup set out to enhance the C language with Simula-like features. C was chosen because it was general-purpose, fast and used; as well as C and Simula's influences, other languages influenced C++, including ALGOL 68, Ada, CLU and ML. Stroustrup's "C with Classes" added features to the C compiler, including classes, derived classes, strong typing and default arguments. In 1983, "C with Classes" was renamed to "C++", adding new features that included virtual functions, function name and operator overloading, constants, type-safe free-store memory allocation, improved type checking, BCPL style single-line comments with two forward slashes. Furthermore, it included the development of a standalone compiler for Cfront. In 1985, the first edition of The C++ Programming Language was released, which became the definitive reference for the language, as there was not yet an official standard; the first commercial implementation of C++ was released in October of the same year.
In 1989, C++ 2.0 was released, followed by the updated second edition of The C++ Programming Language in 1991. New features in 2.0 included multiple inheritance, abstract classes, static member functions, const member functions, protected members. In 1990, The Annotated C++ Reference Manual was published; this work became the basis for the future standard. Feature additions included templates, namespaces, new casts, a boolean type. After the 2.0 update, C++ evolved slowly until, in 2011, the C++11 standard was released, adding numerous new features, enlarging the standard library further, providing more facilities to C++ programmers. After a minor C++14 update released in December 2014, various new additions were introduced in C++17, further changes planned for 2020; as of 2017, C++ remains the third most popular programming language, behind Java and C. On January 3, 2018, Stroustrup was announced as the 2018 winner of the Charles Stark Draper Prize for Engineering, "for conceptualizing and developing the C++ programming language".
According to Stroustrup: "the name signifies the evolutionary nature of the changes from C". This name is credited to Rick Mascitti and was first used in December 1983; when Mascitti was questioned informally in 1992 about the naming, he indicated that it was given in a tongue-in-cheek spirit. The name comes from C's ++ operator and a common naming convention of using "+" to indicate an enhanced computer program. During C++'s development period, the language had been referred to as "new C" and "C with Classes" before acquiring its final name. Throughout C++'s life, its development and evolution has been guided by a set of principles: It must be driven by actual problems and its features should be useful in real world programs; every feature should be implementable. Programmers should be free to pick their own programming style, that style should be supported by C++. Allowing a useful feature is more important than preventing every possible misuse of C++, it should provide facilities for organising programs into separate, well-defined parts, provide facilities for combining separately developed parts.
No implicit violations of the type system (but allow explicit violations.
Alice in Chains
Alice in Chains is an American rock band from Seattle, formed in 1987 by guitarist and vocalist Jerry Cantrell and drummer Sean Kinney, who recruited bassist Mike Starr and lead vocalist Layne Staley. Starr was replaced by Mike Inez in 1993. William DuVall joined the band in 2006 as co-lead vocalist and rhythm guitarist, replacing Staley, who died in 2002; the band took its name from the glam metal band Alice N' Chains. Although associated with grunge music, the band's sound incorporates heavy metal elements. Since its formation, Alice in Chains has released six studio albums, three EPs, three live albums, four compilations, two DVDs, 32 music videos and 31 singles; the band is known for its distinctive vocal style, which included the harmonized vocals between Staley and Cantrell. Cantrell started to sing lead vocals on the 1992 acoustic EP Sap, his role continued to grow in the following albums, making Alice in Chains a two-vocal band. Alice in Chains rose to international fame as part of the grunge movement of the early 1990s, along with other Seattle bands such as Nirvana, Pearl Jam, Soundgarden.
The band was one of the most successful music acts of the 1990s, selling over 30 million records worldwide, over 14 million records in the US alone, with two No. 1 albums and six Top 10 albums on the Billboard 200 chart. The band has had 18 Top 10 songs on Billboard's Mainstream Rock Tracks chart, 5 No. 1 hits, 11 Grammy Award nominations. Their debut album, featuring the hit single "Man in the Box", was released in 1990 and has been certified double-platinum by the RIAA, selling over two million copies. In 1992, the band's second album, was released to critical acclaim and was certified quadruple platinum, their second acoustic EP, Jar of Flies, debuted at No. 1 on the Billboard 200 chart in 1994, becoming the first EP and first Alice in Chains release to top the charts, it has been certified triple platinum. The band's third album, Alice in Chains debuted at No. 1 on the Billboard 200 in 1995 and is certified double platinum. Although never disbanding, Alice in Chains was plagued by extended inactivity from 1996 onwards due to Staley's substance abuse, which resulted in his death in 2002.
The band reunited in 2005 for a live benefit show. They toured with William DuVall taking over as lead vocalist full-time; the new line-up released the band's fourth studio album, Black Gives Way to Blue, in 2009, which debuted at No. 5 on the Billboard 200, received gold certification by the RIAA and two Grammy nominations. The lead single, "Check My Brain", became the first Alice in Chains song to chart on the Billboard Hot 100, peaking at No. 92. Their fifth studio album, The Devil Put Dinosaurs Here, was released in 2013 and debuted at No. 2 on the Billboard 200. The band released several videos in support of these albums. Alice in Chains' sixth studio album, Rainier Fog, was released on August 24, 2018, debuted at No. 12 on the Billboard 200 and received a Grammy nomination for Best Rock Album. Before the formation of Alice in Chains, then-drummer Layne Staley landed his first gig as a vocalist when he auditioned to sing for a local glam metal band known as Sleze after receiving some encouragement from his stepbrother Ken Elmer.
Other members of this group at that time were guitarists Johnny Bacolas and Zoli Semanate, drummer James Bergstrom, bassist Byron Hansen. This band went through several lineup changes culminating with Nick Pollock as their sole guitarist and Bacolas switching to bass before discussions arose about changing their name to Alice in Chains; this was prompted by a conversation that Bacolas had with Russ Klatt, the lead singer of Slaughter Haus 5, about backstage passes. One of the passes said "Welcome to Wonderland", they started talking about that being a reference to Alice in Wonderland, until Klatt said, "What about Alice in Chains? Put her in bondage and stuff like that." Bacolas thought the name "Alice in Chains" was cool and brought it up to his Sleze bandmates and everyone liked it, so they decided to change the name of the band. Due to concerns over the reference to female bondage, the group chose to spell it differently as Alice N' Chains to allay any parental concerns, though Staley's mother Nancy McCallum has said she was still not happy with this name at first.
According to Bacolas, the decision to use the apostrophe-N combination in their name had nothing to do with the Los Angeles band Guns N' Roses. The name change happened in 1986, a year before Guns N' Roses became a household name with their first album Appetite for Destruction, released in July 1987. Staley met guitarist Jerry Cantrell at a party in Seattle around August 1987. A few months before that, Cantrell had watched a concert of Staley's then-band, Alice N' Chains, in his hometown at the Tacoma Little Theatre, was impressed by his voice. Cantrell was homeless after being kicked out of his family's house, so Staley invited Cantrell to live with him at the rehearsal studio Music Bank, the two struggling musicians became roommates. Alice N' Chains soon disbanded, Staley joined a funk band. Cantrell's band, Diamond Lie, broke up and he wanted to form a new band, so Staley gave him the phone number of Melinda Starr, the girlfriend of drummer Sean Kinney, so that Cantrell could talk to him.
Cantrell set up a meeting with Kinney. Kinney and his girlfriend went to the Music Bank and listened to Cantrell's demos, who mentioned that they needed a bass player to jam with them, he had someone in mind: Mike Starr, with whom Cantrell had played in a band in Burien called Gypsy Rose. Kinney mentioned that his girlfriend was Mike Starr
Jar of Flies
Jar of Flies is the third studio EP by the American rock band Alice in Chains, released on January 25, 1994, through Columbia Records. The album was self-produced by the band and recorded over the course of a week at the London Bridge Studio in Seattle. Jar of Flies is regarded as a continuation of the acoustic and melancholic sound that Alice in Chains adopted with Sap in 1992; the album was promoted by the singles "No Excuses" and "I Stay Away". Jar of Flies was commercially successful. On February 12, 1994, Jar of Flies debuted at No. 1 in the Billboard 200 chart, the first EP in music history to do so. On September 19, 1995, Jar of Flies was certified triple-platinum by the RIAA after exceeding the threshold of 1.5 million copies sold. In Canada, Jar of Flies was certified double-platinum for the sale of 200,000 copies. In Great Britain, the album was certified silver after selling 60,000 copies. During Alice in Chains' June–August 1993 appearance at Lollapalooza, guitarist Jerry Cantrell called record producer Toby Wright with a proposal to collaborate on new material.
Wright booked ten days at the London Bridge Studio. Despite Cantrell's assurances, the band did not have any planned tracks. Drummer Sean Kinney had said "After playing loud music for a year, we'd come home and the last thing we wanted to do was crank up the amps right away; that stuff whenever we had downtime. We did Jar of Flies to see. We just went into the studio with no songs written, it all fell into place. The sounds and the tones were good. We thought it would be a waste to put that material out."The first session took place on September 7, 1993. Vocalist Layne Staley said the band "just wanted to go into the studio for a few days with our acoustic guitars and see what happened. We never planned on the music we made at that time to be released, but the record label heard it and they liked it. For us, it was just the experience of four guys getting together in the studio and making some music." The album's sessions lasted 14–18 hours a day, recording was complete within seven days. Assistant engineer Jonathan Plum described the sessions as "exhaustive".
The album was recorded on tape on a Neve 80-68 mixing console because Wright wanted the album's acoustic sound to be as natural as possible. Staley instructed; the album's tracks were recorded within one or two takes. The album's acoustic guitar sound was focused on. Wright recalled that "at some points we overdubbed some acoustics with micing those acoustics, but when they were recording live off the floor, I'd use whatever pick-ups had in his guitars at the time, trying to keep that sound as close to acoustic-sounding as possible. So that it sounded like it was an acoustic guitar instead of an electrified acoustic guitar." Cantrell played using Ovation guitars during the album's sessions. To reflect the recording's acoustic climate, Kinney sometimes used brushes to obtain a softer feel. AKG 414 microphones were used for overhead registration, while D-12s were used for the floor and rack toms, 421s were placed on the kick drum. 451s and 57s were mounted on the top side of the snare drum, while a 441 was fitted on the bottom side.
The characteristic syncopated drum opening in "No Excuses" was a result of Kinney's improvised experimentation with side-stick drumming. Wright was not an advocate of the technique and said that they "eventually wound up with some bongos and some smaller drums set up over the hi-hat that we incorporated into that groove." Staley arranged the album's vocal harmonies. Wright recalled the pace of Staley's work as quick, that the vocal tracks were recorded within one or two takes via a Neumann M-49 microphone. Cantrell performed the lead vocals in the track "Don't Follow". Wright described Cantrell as an "awesome" singer, stressed that "you couldn't have done all those harmonies without him." The album's sessions concluded on September 14. Wright mixed the album at Scream Studio in Los Angeles, California from September 17–22. Due to the dominance of acoustic instruments in Jar of Flies, the album is considered a continuation of the sound adopted by the band on the 1992 EP Sap; the album demonstrates the band's wide range by offering a variety of tracks with an acoustic texture, featuring elements of album-oriented rock, blues rock, alternative rock, classic rock.
Steve Huey of Allmusic stressed that "the mood is still hopelessly bleak, but the poignant, introspective tone produces a sense of acceptance that's soothing, in a funereal sort of way. Jerry Cantrell's arrangements keep growing more layered. Paul Evans of Rolling Stone stated that Staley's vocals on the tracks "Swing on This" and "Rotten Apple" "ow as much to Styx and Kansas as Jerry Cantrell’s guitars do to Black Sabbath", that the vocals "evoke pathos as well as anger." Tom Sinclair of Entertainment Weekly compared "No Excuses" to classic rock of the 70's and described "Swing on This" as "postmodern boogie-woogie". The album's lyrics are dark and gloomy, with Huey writing that "Jar of Flies is about living with the consequences, full of felt reflections on loneliness, self-imposed isolation, lost human connections." Jon Pareles o
It describes 18 elements comprising the initial simple design of HTML. Except for the hyperlink tag, these were influenced by SGMLguid, an in-house Standard Generalized Markup Language -based documentation format at CERN. Eleven of these elements still exist in HTML 4. HTML is a markup language that web browsers use to interpret and compose text and other material into visual or audible web pages. Default characteristics for every item of HTML markup are defined in the browser, these characteristics can be altered or enhanced by the web page designer's additional use of CSS. Many of the text elements are found in the 1988 ISO technical report TR 9537 Techniques for using SGML, which in turn covers the features of early text formatting languages such as that used by the RUNOFF command developed in the early 1960s for the CTSS operating system: these formatting commands were derived from the commands used by typesetters to manually format documents. However, the SGML concept of generalized markup is based on elements rather than print effects, with the separation of structure and markup.
Berners-Lee considered HTML to be an application of SGML. It was formally defined as such by the Internet Engineering Task Force with the mid-1993 publication of the first proposal for an HTML specification, the "Hypertext Markup Language" Internet Draft by Berners-Lee and Dan Connolly, which included an SGML Document type definition to define the grammar; the draft expired after six months, but was notable for its acknowledgment of the NCSA Mosaic browser's custom tag for embedding in-line images, reflecting the IETF's philosophy of basing standards on successful prototypes. Dave Raggett's competing Internet-Draft, "HTML+", from late 1993, suggested standardizing already-implemented features like tables and fill-out forms. After the HTML and HTML+ drafts expired in early 1994, the IETF created an HTML Working Group, which in 1995 completed "HTML 2.0", the first HTML specification intended to be treated as a standard against which future implementations should be based. Further development under the auspices of the IETF was stalled by competing interests.
Since 1996, the HTML specifications have been maintained, with input from commercial software vendors, by the World Wide Web Consortium. However, in 2000, HTML became an international standard. HTML 4.01 was published in late 1999, with further errata published through 2001. In 2004, development began on HTML5 in the Web Hypertext Application Technology Working Group, which became a joint deliverable with the W3C in 2008, completed and standardized on 28 October 2014. November 24, 1995 HTML 2.0 was published as RFC 1866. Supplemental RFCs added capabilities: November 25, 1995: RFC 1867 May 1996: RFC 1942 August 1996: RFC 1980 January 1997: RFC 2070 January 14, 1997 HTML 3.2 was published as a W3C Recommendation. It was the first version developed and standardized by the W3C, as the IETF had closed its HTML Working Group on September 12, 1996. Code-named "Wilbur", HTML 3.2 dropped math formulas reconciled overlap among various proprietary extensions and adopted most of Netscape's visual markup tags.
Netscape's blink element and Microsoft's marquee element were omitted due to a mutual agreement between the two companies. A markup for mathematical formu
A tag editor is a piece of software that supports editing metadata of multimedia file formats, rather than the actual file content. These are taggers for common audio tagging formats like ID3, APE, Vorbis comments, but can be taggers for JPEG, PDF and TIFF metadata. A common purpose of tag editors is to correct or update metadata and enable sorting and grouping of multimedia files, for example music collections; this happens in a batch processing mode so that one doesn't have to manually edit every file on its own. Media players such as iTunes, Foobar2000 or Winamp, as well as dedicated tag editing programs allow users to manually edit tag and song file information, including composer and release year. Dedicated tag editors may feature batch creating tags from file names and vice versa. One type of tag editor compares the existing metadata in an audio file's tags with the information from online music databases, such as Gracenote, freedb, Zortam Music Internet Database or MusicBrainz. Once a match is found, complementary metadata information may be downloaded.
This process is semi-automatic. An acoustic fingerprint is a unique code generated from an audio waveform. Depending upon the particular algorithm, acoustic fingerprints can be used to automatically categorize or identify an audio sample. Practical uses of acoustic fingerprinting include broadcast monitoring, identification of music and ads being played, peer-to-peer network monitoring, sound effect library management, video identification. In hash function, for audio identification, such as finding out whether an MP3 file matches one of a list of known items, one could use a conventional hash function such as MD5, but this would be sensitive to likely perturbations such as time-shifting, CD read errors, different compression algorithms or implementations or changes in volume. Using something like MD5 is useful as a first pass to find exactly-identical files, but another, more advanced algorithm is required to find all items that would nonetheless be interpreted as identical by a human listener.
The following is a list of tag editors. Media players have tag editing capabilities and are not included. Free and open-source: EasyTag – Supports MP3, MP2, FLAC, Ogg, MP4, Musepack MPC and Monkey's Audio formats. Available for Linux and Windows. Ex Falso – Supports MP3, Ogg, FLAC, Wavpack, MP4, WMA, MIDI, Monkey’s Audio. Available for Windows, Mac OS, FreeBSD. Kid3 – Supports MP3, Ogg/Vorbis, FLAC, MPC, MP4/AAC, MP2, Speex, TrueAudio, WavPack, WMA, WAV, AIFF files and tracker modules formats. Available for FreeBSD, Mac OS and Windows. MusicBrainz Picard – Supports MP3, Ogg, FLAC, WavPack, OptimFROG, Monkey's Audio, MP4, Windows Media Audio. Available for FreeBSD, Mac OS and Windows. Puddletag – Supports FLAC, APE, MP3, MPEG-4, MPC, OGG, OptimFROG, TAK, WMA, WavPack. Available for FreeBSD and Linux. Vorbiscomment and lltag are popular CLI tools for Linux. Proprietary software: File Explorer – has limited tag editing capabilities on supported file formats such as MP3 and WMA Jaikoz – Commercial package, available for Windows, Linux and OS X that uses the MusicBrainz database for auto-tagging.
Supports embedded auto-lyrics. Mp3tag – Freeware for Windows. Supports FLAC, APE, MP3, MPEG-4, MPC, OGG, OptimFROG, TAK, WMA, WavPack. ID3-TagIT -- free but proprietary software supporting ID3v1.1, ID3v2.3 and ID3v2.4 tags. Development stopped in 2013. Version 3.2.1 can still be found. Free and open-source: jBrout – Available for Linux and Windows ExifTool – Available for Windows, Linux and OS X DigiKam – Available for Linux, FreeBSD, OS X and Windows F-Spot – Available for Unix-like OSes gThumb – Available for Unix-like OSes Shotwell – Available for Unix-like Proprietary software: iPhoto – Available for OS X IrfanView – Available for Windows, Linux and OS X File Explorer has limited tag editing capabilities on MP4 and WMV files
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