edX is a massive open online course (MOOC) provider. It hosts online university-level courses in a wide range of disciplines to a worldwide student body, including some courses at no charge. It also conducts research into learning based on how people use its platform. EdX is a nonprofit organization and runs on the free Open edX open-source software platform.[4]

The Massachusetts Institute of Technology and Harvard University created edX in May 2012. More than 70 schools, nonprofit organizations, and corporations offer or plan to offer courses on the edX website.[5] As of 29 December 2017, edX has around 14 million students taking more than 1,800 courses online.[2]

Type of site
Online education
Available inEnglish, Mandarin, French, Hindi, Spanish
OwneredX Inc.
Created byMassachusetts Institute of Technology and Harvard University
Alexa rankPositive decrease 983 (April 2018) [1]
Users~14 million (December 2017) [2]
LaunchedMay 2012
Current statusActive
Content license
Copyright of edX [3]


EdX courses consist of weekly learning sequences. Each learning sequence is composed of short videos interspersed with interactive learning exercises, where students can immediately practice the concepts from the videos. The courses often include tutorial videos that are similar to small on-campus discussion groups, an online textbook, and an online discussion forum where students can post and review questions and comments to each other and teaching assistants. Where applicable, online laboratories are incorporated into the course. For example, in edX's first MOOC — a circuits and electronics course — students built virtual circuits in an online lab.[6]

EdX offers certificates of successful completion and some courses are credit-eligible. Whether or not a college or university offers credit for an online course is within the sole discretion of the school.[7] EdX offers a variety of ways to take courses, including verified courses where students have the option to audit the course (no cost) or to work toward an edX Verified Certificate (fees vary by course). For courses announced before December 7, 2015, there was an option to take honor code courses to work toward an Honor Code Certificate (no cost).[8] EdX also offers XSeries Certificates for completion of a bundled set of two to seven verified courses in a single subject (cost varies depending on the courses).[9][10]


In addition to educational offerings, edX is utilized for research into learning and distance education by collecting learners' clicks and analyzing the data, as well as collecting demographics from each registrant.[7][11][12][13] A team of researchers at Harvard and MIT, led by David Pritchard and Lori Breslow, released their initial findings in 2013.[14] EdX member schools and organizations also conduct their own research using data collected from their courses.[15] Research focuses on improving retention, course completion and learning outcomes in traditional campus courses and online.[16]

EdX has engaged in a number of partnerships with educational institutions in the United States, China, Mongolia, Japan, and more to utilize edX courses in "blended classrooms."[15] In blended learning models, traditional classes include an online interactive component. San Jose State University (SJSU) partnered with edX to offer 6.00xL Introduction to Computer Science and Programming, as a blended course at SJSU and released an initial report on the project in February 2013. Initial results showed a decrease in failure rates from previous semesters. The percentage of students required to retake the course dropped from 41% under the traditional format to 9% for those taking the edX blended course.[17] In Spring 2013, Bunker Hill Community College and Massachusetts Bay Community College implemented a SPOC, or small private online course. The colleges incorporated an MIT-developed Python programming course on EdX into their campus-based courses, and reported positive results.[18][19]

Open edX

Versions[20] Date
Hawthorn 2018-08-07
Ginkgo 2017-08-14
Ficus 2017-02-23
Eucalyptus 2016-08-26
Dogwood 2016-02-11
Cypress 2015-08-13
Birch 2015-02-24
Aspen 2014-10-28

Open edX is the open-source platform software developed by EdX and made freely available to other institutions of higher learning that want to make similar offerings. On June 1, 2013, edX open sourced its entire platform.[21] The source code can be found on GitHub.[22][23]

The Open edX server-side software is almost entirely based on "Python, with Django as the web application framework."[24]


In March 2014, edX appointed Wendy Cebula, former COO of Vistaprint, as its President and Chief Operating Officer. CEO Anant Agarwal of MIT stated that Cebula would bring "an entrepreneurial aspect" and help the nonprofit to access "commercial opportunities."[25] Alan M. Garber, Provost of Harvard University, assisted by Michael D. Smith, a computer scientist who is Dean of the Faculty of Arts and Sciences, handles Harvard contributions. The design of a viable business model for sustainability of the enterprise is in progress.[12]


External audio
Interview with edX President Anant Agarwal [17:47] on the first anniversary of edX, Degree of Freedom[26]

EdX was founded in May 2012 by scientists from Harvard and MIT. Gerry Sussman, Anant Agarwal, Chris Terman, and Piotr Mitros taught the first edX course on circuits and electronics from MIT, drawing 155,000 students from 162 countries. In 2013 they partnered with Stanford and in June 2013 they reached 1 million students.[27] edx.org released as open source, creating Open edX.

In September 2014 edX announced a high school initiative.[28]

In October 2014 edX announced Professional Education courses,[29] and in March 2015 it partnered with Microsoft.[30]

In April 2015, edX partnered with Arizona State University to launch the Global Freshman Academy.[31]

In September 2016, edX launched 19 MicroMasters programs.[32]

In February 2017, edX launched 16 MicroMasters programs.[33][34]

In January 2018, edX partnered with Microsoft and General Electric to provide subsidized online courses and guaranteed job interviews.[35]

On January 9, 2018, Tech Mahindra partnered with edX to re-skill workforce on new tech areas.[36]

Participating institutions

In late 2013, several countries and private entities announced their adoption of the edX open source platform to launch new initiatives. Ten Chinese universities joined together to form an online education initiative in China, called XuetangX.[37] 120 higher education institutions in France joined under the direction of the French Ministry of Education to offer online courses throughout France,[38] the Queen Rania Foundation for Education and Development (QRF) created Edraak as the first MOOC portal for the Arab world,[39] the International Monetary Fund is using the edX platform to pilot online training courses in economics and finance,[40] and Tenaris corporation is using the platform to expand its corporate training and education for its employees.[41]

As of March 2017, edX has more than 110 partners, including universities, for-profit organizations and NGOs.[42]


  1. ^ "Edx.org Traffic, Demographics and Competitors - Alexa". www.alexa.com. Retrieved 2018-03-27.
  2. ^ a b "EdX's 2017: Year in Review". edX. 4 January 2018. Retrieved 27 March 2018.
  3. ^ "edX Terms of Service".
  4. ^ "About Us". edX.
  5. ^ "Schools and Partners". edX.
  6. ^ Studying Learning in the Worldwide Classroom: Research Into edX's First MOOC, RPA Journal, June 14, 2013, By Lori Breslow, David E. Pritchard, Jennifer DeBoer, Glenda S. Stump, Andrew D. Ho, and Daniel T. Seaton.
  7. ^ a b "edX FAQs". edX. Retrieved August 26, 2012.
  8. ^ http://blog.edx.org/news-about-edx-certificates?track=blog
  9. ^ "Verified Certificate". edX.
  10. ^ "XSeries". edX.
  11. ^ Laura Pappano (Nov. 2, 2012), "The Year of the MOOC," The New York Times.
  12. ^ a b Nick DeSantis (May 2, 2012). "Harvard and MIT Put $60-Million Into New Platform for Free Online Courses". The Chronicle of Higher Education. Retrieved May 3, 2012.
  13. ^ Tamar Lewin (May 2, 2012). "Harvard and M.I.T. Team Up to Offer Free Online Courses". The New York Times. Retrieved May 3, 2012.
  14. ^ Studying Learning in the Worldwide Classroom: Research Into edX's First MOOC, RPA Journal, June 14, 2013, By Lori Breslow, David E. Pritchard, Jennifer DeBoer, Glenda S. Stump, Andrew D. Ho, and Daniel T. Seaton.
  15. ^ a b "edX". edX.
  16. ^ Faculty of Arts and Sciences/Harvard College Fun (Sept/Oct 2013), "On the Leading Edge of Teaching."
  17. ^ Ellen Junn and Cathy Cheal of San Jose State University report on the universities' efforts to incorporate MIT's Electronics and Circuits course 6.002x Little Hoover Commission Public Hearing Testimony
  18. ^ "MOOCs in the Community College: Implications for Innovation in the Classroom - Online Learning Consortium, Inc". onlinelearningconsortium.org.
  19. ^ "SPOCs: Small private online classes may be better than MOOCs". Slate Magazine.
  20. ^ Open edX Named Releases https://edx.readthedocs.io/projects/edx-developer-docs/en/latest/named_releases.html
  21. ^ "Stanford to collaborate with edX to develop a free, open source online learning platform". Stanford University.
  22. ^ https://github.com/edx/
  23. ^ "EdX-platform". GitHub.
  24. ^ "Open edX Architecture". edX Inc. Retrieved 30 April 2017.
  25. ^ "With Eye Toward Financial Self-Sufficiency, edX Hires Businesswoman Cebula as President and COO". Harvard Crimson. 2014-03-25. Retrieved 2014-04-08.
  26. ^ "Interview with edX President Anant Agarwal". Degree of Freedom (MOOC blog). May 10, 2013. Retrieved May 10, 2013.
  27. ^ Conway, Madeline R. (June 20, 2013). "EdX Enrollment Reaches Seven Digits". The Harvard Crimson. Retrieved July 19, 2014.
  28. ^ Rocheleau, Matt (September 10, 2014). "Online education company edX offering free high school courses". The Boston Globe. Retrieved September 10, 2014.
  29. ^ Korn, Melissa (October 1, 2014). "Corporate Training Gets an Online Refresh". The Washington Post. Retrieved October 22, 2014.
  30. ^ "Microsoft and edX Partner to Deliver Real World Skill Learning (EdSurge News)". Retrieved 2015-04-27.
  31. ^ Anderson, Nick (April 22, 2015). "Arizona State University to Offer Freshman Year Online, For Credit". The Washington Post. Retrieved April 22, 2015.
  32. ^ "Thirteen universities adopt MicroMasters and launch 18 new programs via edX". MIT News. Retrieved 2017-03-22.
  33. ^ "edX Expands MicroMasters Programs With Data Science, Digital Leadership and More -- Campus Technology". Campus Technology. Retrieved 2017-03-22.
  34. ^ "EdX Launches Professional Certificate Programs | Inside Higher Ed". Retrieved 2018-05-15.
  35. ^ "EdX Partners with Microsoft, GE to Provide Subsidized Courses | News | The Harvard Crimson". www.thecrimson.com. Retrieved 2018-05-15.
  36. ^ "TechM partners edX to re-skill workforce on new tech areas - Times of India". The Times of India. Retrieved 2018-05-15.
  37. ^ "Open Source Platform Chosen to Power China's New Online Education Portal". edX. 2013-10-10. Retrieved 2014-01-01.
  38. ^ "to Work with French Ministry of Higher Education to Create National Online Learning Portal". edX. 2013-10-03. Retrieved 2014-01-01.
  39. ^ "Queen Rania Foundation Partners with edX to Create First MOOC Portal for the Arab World". edX. 2013-11-08. Retrieved 2014-01-01.
  40. ^ "IMF and edX Join Forces to Pilot Online Economics and Financial Courses". edX. 2013-06-19. Retrieved 2014-01-01.
  41. ^ 4-traders (2013-11-12). "Tenaris S.A. : Tenaris to Adopt edX Platform for Corporate Training". 4-Traders. Retrieved 2014-01-01.
  42. ^ "Schools & Partners". edX. 2017. Retrieved 2017-03-23.

External links

Anant Agarwal

Anant Agarwal is an Indian computer architecture researcher. He is a professor of Electrical Engineering and Computer Science at the Massachusetts Institute of Technology (MIT), where he led the development of Alewife, an early cache coherent multiprocessor, and also has served as director of the MIT Computer Science and Artificial Intelligence Laboratory. He is the founder and CTO of Tilera, a fabless semiconductor company focusing on scalable multicore embedded processor design. He also serves as the CEO of edX, a joint partnership between MIT and Harvard University that offers free online learning.


The CPUID instruction (identified by a CPUID opcode) is a processor supplementary instruction (its name derived from CPU IDentification) for the x86 architecture allowing software to discover details of the processor. It was introduced by Intel in 1993 when it introduced the Pentium and SL-enhanced 486 processors.A program can use the CPUID to determine processor type and whether features such as MMX/SSE are implemented.


Maurizio Colella (born 2 November 1976), better known by his stage name EDX, is a Swiss DJ and Grammy-nominated producer. The #1 Swiss artist on Spotify, he was proclaimed a genius by British electronic dance music magazine Mixmag for his production and remixing talent. EDX is currently signed to the Spinnin' Deep sublabel of Spinnin' Records, although also releases via his own label Sirup Music and its sublabel Enormous Tunes. His radio mix show, No Xcuses, debuted in 2011 on Sirius XM and is now broadcast weekly on the Evolution platform on iHeartRadio.

EDX London

EDX London was a derivatives exchange managed by the London Stock Exchange that was absorbed into the Turquoise trading platform in 2011. The market was set up in 2003 to combine the liquidity and expertise of the LSE with advanced derivatives technology offered by Sweden's OMX AB. Members of EDX could trade either standardised or flexible futures and options on indices or single stocks. Trading took place on the three Scandinavian linked exchanges, the Stockholm Stock Exchange, Copenhagen Stock Exchange, and Oslo Børs as well as some Russian stocks.

The exchange utilised the electronic trading platform Sola Trading and trades were cleared via LCH.Clearnet. At its peak there were approximately 150 contracts available for trading.

The cooperation between EDX London and OMX was terminated in November 2009 when Nasdaq took over OMX. Most of the contracts were moved to Nasdaq OMX with only the Norwegian derivatives remaining with EDX London. NasdaqOMX moved these contracts to its Genium Inet electronic trading platform in 2010. The LSE merged the remaining EDX London contracts with its Turquoise trading service that it had acquired in 2009.

Electrodiagnostic medicine

Electrodiagnosis (EDX) is a method of medical diagnosis that obtains information about diseases by passively recording the electrical activity of body parts (that is, their natural electrophysiology) or by measuring their response to external electrical stimuli (evoked potentials). The most widely used methods of recording spontaneous electrical activity are various forms of electrodiagnostic testing (electrography) such as electrocardiography (ECG), electroencephalography (EEG), and electromyography (EMG). Electrodiagnostic medicine (also EDX) is a medical subspecialty of neurology, clinical neurophysiology, cardiology, and physical medicine and rehabilitation. Electrodiagnostic physicians apply electrophysiologic techniques, including needle electromyography and nerve conduction studies to diagnose, evaluate, and treat people with impairments of the neurologic, neuromuscular, and/or muscular systems. The provision of a quality electrodiagnostic medical evaluation requires extensive scientific knowledge that includes anatomy and physiology of the peripheral nerves and muscles, the physics and biology of the electrical signals generated by muscle and nerve, the instrumentation used to process these signals, and techniques for clinical evaluation of diseases of the peripheral nerves and sensory pathways.

Energy-dispersive X-ray spectroscopy

Energy-dispersive X-ray spectroscopy (EDS, EDX, EDXS or XEDS), sometimes called energy dispersive X-ray analysis (EDXA) or energy dispersive X-ray microanalysis (EDXMA), is an analytical technique used for the elemental analysis or chemical characterization of a sample. It relies on an interaction of some source of X-ray excitation and a sample. Its characterization capabilities are due in large part to the fundamental principle that each element has a unique atomic structure allowing a unique set of peaks on its electromagnetic emission spectrum (which is the main principle of spectroscopy).

To stimulate the emission of characteristic X-rays from a specimen, a high-energy beam of charged particles such as electrons or protons (see PIXE), or a beam of X-rays, is focused into the sample being studied. At rest, an atom within the sample contains ground state (or unexcited) electrons in discrete energy levels or electron shells bound to the nucleus. The incident beam may excite an electron in an inner shell, ejecting it from the shell while creating an electron hole where the electron was. An electron from an outer, higher-energy shell then fills the hole, and the difference in energy between the higher-energy shell and the lower energy shell may be released in the form of an X-ray. The number and energy of the X-rays emitted from a specimen can be measured by an energy-dispersive spectrometer. As the energies of the X-rays are characteristic of the difference in energy between the two shells and of the atomic structure of the emitting element, EDS allows the elemental composition of the specimen to be measured.

France Université Numérique

France université numérique (FUN) is the French national platform to promote the use of massive open online courses (MOOCs).The portal is supported by the American open edX open source platform, and supported by Google since September 2013. The audiovisual content is hosted on Amazon Web Services servers.At its launch, the platform was endowed by the government, a budget of eight million euros.

John C. Mitchell

John Clifford Mitchell is professor of computer science and (by courtesy) electrical engineer at Stanford University. He has published in the area of programming language theory and computer security.John C. Mitchell is the Vice Provost for Teaching and Learning at Stanford University, the Mary and Gordon Crary Family Professor in Computer Science and Electrical Engineering at Stanford University, co-director of the Stanford Computer Security Lab, and Professor (by courtesy) of Education. He is a member of the steering committee for Stanford University's Cyber Initiative. Mitchell has been Vice Provost at Stanford University since 2012, first as the inaugural Vice Provost for Online Learning and now in a broader role for Teaching and Learning. Under Mitchell's direction, the Office of the Vice Provost for Teaching and Learning (VPTL) is advancing teaching and learning through faculty-driven initiatives and research, transforming education in Stanford's classrooms and beyond.

Mitchell's first research project in online learning started in 2009 when he and six undergraduate students built Stanford CourseWare, an innovative platform that expanded to support interactive video and discussion. CourseWare served as the foundation for initial flipped classroom experiments at Stanford and helped inspire the first massive open online courses (MOOCs) from Stanford that captured worldwide attention in 2011.

The Office of the Vice Provost for Online Learning was as established in August 2012, after Mitchell served as John L. Hennessy's — Stanford University's 10th President — special assistant for educational technology and chaired a faculty committee that established initial priorities for Stanford and developed intellectual property guidelines for publicly released online courses.

To help build faculty experience and a catalogue of online material, Vice Provost Mitchell launched a faculty seed grant program in Summer 2012. This program has helped faculty across campus transform their Stanford campus courses and release public courses to the world, generating informed discussion and debate among faculty in the process.In addition to supporting delivery of digital course content, the VPTL engineering team is working to expand the features of Lagunita, Stanford's instance of the open-source release of the edX platform. Mitchell and his team, in partnership with edX, announced the release of Open edX in June 2013: an open-source hosting platform, providing a customizable alternative for all colleges and universities and supporting open educational research and innovation.Stanford's online courses are generating a wealth of course participant data. In collaboration with Stanford centers of scholarship such as the Lytics Lab, which is jointly supervised by Mitchell, and Mitchell Stevens and Candace Thille of the Graduate School of Education, VPTL is playing a key role in evaluating educational outcomes and improving online learning based on data-driven research and iterative design.

In May 2014, Mitchell's team issued a comprehensive report to share benchmark information with other institutions of higher education.

Mitchell holds a B.S. from Stanford University and a M.S. and Ph.D. from the Massachusetts Institute of Technology (MIT). He has served on the editorial board of ten academic journals, acted as consultant and advisor to numerous companies, and spent sabbaticals at the Newton Institute for Mathematical Science and Coverity, Inc. Mitchell is the author of two books, over 170 research papers, and is among the most-cited scholars in computer science.

Jonas Blue

Guy James Robin (born 2 August 1989), known professionally as Jonas Blue, is an English DJ, songwriter, record producer and remixer based in London who produces music which blends dance music with pop sensibilities.

Low-level programming language

A low-level programming language is a programming language that provides little or no abstraction from a computer's instruction set architecture—commands or functions in the language map closely to processor instructions. Generally this refers to either machine code or assembly language. The word "low" refers to the small or nonexistent amount of abstraction between the language and machine language; because of this, low-level languages are sometimes described as being "close to the hardware". Programs written in low-level languages tend to be relatively non-portable.

Low-level languages can convert to machine code without a compiler or interpreter— second-generation programming languages use a simpler processor called an assembler— and the resulting code runs directly on the processor. A program written in a low-level language can be made to run very quickly, with a small memory footprint. An equivalent program in a high-level language can be less efficient and use more memory. Low-level languages are simple, but considered difficult to use, due to numerous technical details that the programmer must remember. By comparison, a high-level programming language isolates execution semantics of a computer architecture from the specification of the program, which simplifies development.

Low-level programming languages are sometimes divided into two categories: first generation and second generation.


MITx is the massive open online course (MOOC) program at Massachusetts Institute of Technology. A constituent program of MIT’s Office of Digital Learning, MITx produces MOOCs from MIT departments and faculty that appear on the edX platform. MITx also supports residential experiments with scalable learning technologies and research on digital learning. MOOCs offered through edX by MITx are open-enrollment and free to take. In September 2012, edX and MITx introduced the option to receive an ID verified certificate on some courses.

Massive open online course

A massive open online course (MOOC ) is an online course aimed at unlimited participation and open access via the web. In addition to traditional course materials, such as filmed lectures, readings, and problem sets, many MOOCs provide interactive courses with user forums to support community interactions among students, professors, and teaching assistants (TAs), as well as immediate feedback to quick quizzes and assignments. MOOCs are a recent and widely researched development in distance education, first introduced in 2006 and emerged as a popular mode of learning in 2012.Early MOOCs often emphasized open-access features, such as open licensing of content, structure and learning goals, to promote the reuse and remixing of resources. Some later MOOCs use closed licenses for their course materials while maintaining free access for students.

Michael J. Sandel

Michael J. Sandel (; born 1953) is an American political philosopher. He is the Anne T. and Robert M. Bass Professor of Government Theory at Harvard University Law School, where his course Justice was the university's first course to be made freely available online and on television. It has been viewed by tens of millions of people around the world, including in China, where Sandel was named the "most influential foreign figure of the year" (China Newsweek). He is also known for his critique of John Rawls' A Theory of Justice in his first book, Liberalism and the Limits of Justice (1982).

He also Majored in English

He was elected a Fellow of the American Academy of Arts and Sciences in 2002.


MicroMasters programs are a series of online graduate level courses offered by universities through edX that one can take to develop standalone skills for career advancement or earn graduate level credentials from its respective universities, equivalent to a semester of a full master's degree. It was designed to be the bridge between a bachelor's degree and a master's degree, allowing employees to continue advancing their education without affecting their employment and personal commitments.First launched in September 2016 with 19 MicroMasters programs as an extension of its MOOC, edX eventually expanded to include 17 additional programs in February 2017. As of November 2018, 51 different MicroMasters programs are being offered, with 47 in English, 3 in Spanish, and 1 in French. Each MicroMasters program is sponsored by at least one industry partner, including GE, Microsoft, IBM, Hootsuite, Fidelity, Bloomberg, Walmart, PWC, Booz-Allen Hamilton, and Ford. These programs are designed to bridge the gap between job candidates with a bachelor's degree and companies that want employees with an advanced degree by offering credentials that are equivalent to 25 to 50 percent of a master's degree or 20 to 30 ECTS in Europe.Unlike other existing microcredentials, the MicroMasters programs offer both the benefit of gaining relevant skills in a particular field that can support career development and a pathway to advanced credits in the respective universities offering the course. This includes many of the top universities in the world such as MIT, RIT, UBC, Columbia University, Delft University of Technology, and Indian Institute of Management. The idea of the MicroMasters program started out as an iteration of the existing MOOC model when Coursera first started offering specializations for its various disciplines and a response to the changing nature of work as well as the major skills shortage currently impacting businesses around the world.Further advancement in the MicroMasters program has resulted greater partnership with top-rated universities offering full residential, online, and blended graduate programs at a much lower price in the range of $10,000 to $23,000 starting from October 2018.


OpenCourseWare (OCW) are course lessons created at universities and published for free via the Internet. OCW projects first appeared in the late 1990s, and after gaining traction in Europe and then the United States have become a worldwide means of delivering educational content.

Spinnin' Deep

Spinnin' Deep is a Dutch record label founded in 2009 and specializing in house, deep house, tech house, future house and other EDM genres. It is one of the 40 sub-labels of Spinnin' Records. The label gained success rapidly in 2014, catching up with the parent label Spinnin' Records. The label includes the artists Bolier,Vector, CamelPhat, Chocolate Puma, EDX, Ferreck Dawn, Gregor Salto, Lucas & Steve, Martin Solveig, Mike Mago, Oliver Heldens, Pep & Rash, Sam Feldt, Sander Kleinenberg and Watermät. The label's first release was a compilation called Spinnin' Deep Presents: Tech-House Essentials.

The most successful international single from the label was "Intoxicated" by Martin Solveig and GTA, which reached 11th place in Germany, 81 in Australia, 26 in Ireland, 9 on the Top 40 chart in the Netherlands and 11 in the Single Top 100, and No. 5 in the United Kingdom.


x86 is a family of instruction set architectures based on the Intel 8086 microprocessor and its 8088 variant. The 8086 was introduced in 1978 as a fully 16-bit extension of Intel's 8-bit 8080 microprocessor, with memory segmentation as a solution for addressing more memory than can be covered by a plain 16-bit address. The term "x86" came into being because the names of several successors to Intel's 8086 processor end in "86", including the 80186, 80286, 80386 and 80486 processors.

Many additions and extensions have been added to the x86 instruction set over the years, almost consistently with full backward compatibility. The architecture has been implemented in processors from Intel, Cyrix, AMD, VIA and many other companies; there are also open implementations, such as the Zet SoC platform. Nevertheless, of those, only Intel, AMD, and VIA hold x86 architectural licenses, and are producing modern 64-bit designs.The term is not synonymous with IBM PC compatibility, as this implies a multitude of other computer hardware; embedded systems, as well as general-purpose computers, used x86 chips before the PC-compatible market started, some of them before the IBM PC (1981) itself.

As of 2018, the majority of personal computers and laptops sold are based on the x86 architecture, while other categories—especially high-volume mobile categories such as smartphones or tablets—are dominated by ARM; at the high end, x86 continues to dominate compute-intensive workstation and cloud computing segments.

X86 calling conventions

This article describes the calling conventions used when programming x86 architecture microprocessors.

Calling conventions describe the interface of called code:

The order in which atomic (scalar) parameters, or individual parts of a complex parameter, are allocated

How parameters are passed (pushed on the stack, placed in registers, or a mix of both)

Which registers the called function must preserve for the caller (also known as: callee-saved registers or non-volatile registers)

How the task of preparing the stack for, and restoring after, a function call is divided between the caller and the calleeThis is intimately related with the assignment of sizes and formats to programming-language types.

Another closely related topic is name mangling, which determines how symbol names in the code map to symbol names used by the linker. Calling conventions, type representations, and name mangling are all part of what is known as an application binary interface (ABI).

There are often subtle differences in how various compilers implement these conventions, so it is often difficult to interface code which is compiled by different compilers. On the other hand, conventions which are used as an API standard (such as stdcall) are very uniformly implemented.

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