Mexico the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States. Covering 2,000,000 square kilometres, the nation is the fifth largest country in the Americas by total area and the 13th largest independent state in the world. With an estimated population of over 120 million people, the country is the eleventh most populous state and the most populous Spanish-speaking state in the world, while being the second most populous nation in Latin America after Brazil. Mexico is a federation comprising 31 states and Mexico City, a special federal entity, the capital city and its most populous city. Other metropolises in the state include Guadalajara, Puebla, Tijuana and León. Pre-Columbian Mexico dates to about 8000 BC and is identified as one of five cradles of civilization and was home to many advanced Mesoamerican civilizations such as the Olmec, Teotihuacan, Zapotec and Aztec before first contact with Europeans. In 1521, the Spanish Empire conquered and colonized the territory from its politically powerful base in Mexico-Tenochtitlan, administered as the viceroyalty of New Spain.
Three centuries the territory became a nation state following its recognition in 1821 after the Mexican War of Independence. The post-independence period was tumultuous, characterized by economic inequality and many contrasting political changes; the Mexican–American War led to a territorial cession of the extant northern territories to the United States. The Pastry War, the Franco-Mexican War, a civil war, two empires, the Porfiriato occurred in the 19th century; the Porfiriato was ended by the start of the Mexican Revolution in 1910, which culminated with the promulgation of the 1917 Constitution and the emergence of the country's current political system as a federal, democratic republic. Mexico has the 11th largest by purchasing power parity; the Mexican economy is linked to those of its 1994 North American Free Trade Agreement partners the United States. In 1994, Mexico became the first Latin American member of the Organisation for Economic Co-operation and Development, it is classified as an upper-middle income country by the World Bank and a newly industrialized country by several analysts.
The country is considered both a regional power and a middle power, is identified as an emerging global power. Due to its rich culture and history, Mexico ranks first in the Americas and seventh in the world for number of UNESCO World Heritage Sites. Mexico is an ecologically megadiverse country, ranking fourth in the world for its biodiversity. Mexico receives a huge number of tourists every year: in 2018, it was the sixth most-visited country in the world, with 39 million international arrivals. Mexico is a member of the United Nations, the World Trade Organization, the G8+5, the G20, the Uniting for Consensus group of the UN, the Pacific Alliance trade bloc. Mēxihco is the Nahuatl term for the heartland of the Aztec Empire, namely the Valley of Mexico and surrounding territories, with its people being known as the Mexica, it is believed to be a toponym for the valley which became the primary ethnonym for the Aztec Triple Alliance as a result, although it could have been the other way around.
In the colonial era, back when Mexico was called New Spain this territory became the Intendency of Mexico and after New Spain achieved independence from the Spanish Empire it came to be known as the State of Mexico with the new country being named after its capital: the City of Mexico, which itself was founded in 1524 on top of the ancient Mexica capital of Mexico-Tenochtitlan. Traditionally, the name Tenochtitlan was thought to come from Nahuatl tetl and nōchtli and is thought to mean "Among the prickly pears rocks". However, one attestation in the late 16th-century manuscript known as "the Bancroft dialogues" suggests the second vowel was short, so that the true etymology remains uncertain; the suffix -co is the Nahuatl locative, making the word a place name. Beyond that, the etymology is uncertain, it has been suggested that it is derived from Mextli or Mēxihtli, a secret name for the god of war and patron of the Mexica, Huitzilopochtli, in which case Mēxihco means "place where Huitzilopochtli lives".
Another hypothesis suggests that Mēxihco derives from a portmanteau of the Nahuatl words for "moon" and navel. This meaning might refer to Tenochtitlan's position in the middle of Lake Texcoco; the system of interconnected lakes, of which Texcoco formed the center, had the form of a rabbit, which the Mesoamericans pareidolically associated with the moon rabbit. Still another hypothesis suggests that the word is derived from Mēctli, the name of the goddess of maguey; the name of the city-state was transliterated to Spanish as México with the phonetic value of the letter x in Medieval Spanish, which represented the voiceless postalveolar fricative. This sound, as well as the voiced postalveolar fricative, represented by a j, evolved into a voiceless velar fricative during the 16th century; this led to the use of the variant Méjico in many publications in Spanish, most notably in Spain, whereas in Mexico and most other Spanish–speaking countries, México was the preferred spelling. In recent years, the Real Academia Española, which regulates the Spanish l
Free software movement
The free software movement or free/open-source software movement or free/libre open-source software movement is a social movement with the goal of obtaining and guaranteeing certain freedoms for software users, namely the freedom to run the software, to study and change the software, to redistribute copies with or without changes. Although drawing on traditions and philosophies among members of the 1970s hacker culture and academia, Richard Stallman formally founded the movement in 1983 by launching the GNU Project. Stallman established the Free Software Foundation in 1985 to support the movement; the philosophy of the movement is that the use of computers should not lead to people being prevented from cooperating with each other. In practice, this means rejecting "proprietary software", which imposes such restrictions, promoting free software, with the ultimate goal of liberating everyone in cyberspace – that is, every computer user. Stallman notes that this action will promote rather than hinder the progression of technology, since "it means that much wasteful duplication of system programming effort will be avoided.
This effort can go instead into advancing the state of the art". Members of the free software movement believe that all users of software should have the freedoms listed in The Free Software Definition. Many of them hold that it is immoral to prohibit or prevent people from exercising these freedoms and that these freedoms are required to create a decent society where software users can help each other, to have control over their computers; some free software users and programmers do not believe that proprietary software is immoral, citing an increased profitability in the business models available for proprietary software or technical features and convenience as their reasons."While social change may occur as an unintended by-product of technological change, advocates of new technologies have promoted them as instruments of positive social change." This quote by San Jose State professor Joel West explains much of the philosophy, or the reason that the free source movement is alive. If it is assumed that social change is not only affected, but in some points of view, directed by the advancement of technology, is it ethical to hold these technologies from certain people?
If not to make a direct change, this movement is in place to raise awareness about the effects that take place because of the physical things around us. A computer, for instance, allows us so many more freedoms than we have without a computer, but should these technological mediums be implied freedoms, or selective privileges? The debate over the morality of both sides to the free software movement is a difficult topic to compromise respective opposition; the Free Software Foundation believes all software needs free documentation, in particular because conscientious programmers should be able to update manuals to reflect modification that they made to the software, but deems the freedom to modify less important for other types of written works. Within the free software movement, the FLOSS Manuals foundation specialises on the goal of providing such documentation. Members of the free software movement advocate that works which serve a practical purpose should be free; the core work of the free software movement focused on software development.
The free software movement rejects proprietary software, refusing to install software that does not give them the freedoms of free software. According to Stallman, "The only thing in the software field, worse than an unauthorised copy of a proprietary program, is an authorised copy of the proprietary program because this does the same harm to its whole community of users, in addition the developer, the perpetrator of this evil, profits from it." Some supporters of the free software movement take up public speaking, or host a stall at software-related conferences to raise awareness of software freedom. This is seen as important since people who receive free software, but who are not aware that it is free software, will accept a non-free replacement or will add software, not free software. Margaret S. Elliot, a researcher in the Institute for Software at the University of California Irvine, not only outlines many benefits that could come from a free software movement, she claims that it is inherently necessary to give every person equal opportunity to utilize the Internet, assuming that the computer is globally accessible.
Since the world has become more based in the framework of technology and its advancement, creating a selective internet that allows only some to surf the web is nonsensical according to Elliot. If there is a desire to live in a more coexistent world, benefited by communication and global assistance globally free software should be a position to strive for, according to many scholars who promote awareness about the free software movement; the ideas sparked by the GNU associates are an attempt to promote a "cooperative environment" that understands the benefits of having a local community and a global community. A lot of lobbying work has been done against software expansions of copyright law. Other lobbying focusses directly on use of free software by government agencies and government-funded projects; the Venezuelan government implemented a free software law in January 2006. Decree No. 3,390 mandated all government agencies to migrate to free software over a two-year period. Congressmen Edgar David Villanueva and Jacques Rodrich Ackerman have been instrumental in introducing free software in Peru, with bill 1609 on "Free Software in Public Administration".
The incident invited the attention of Microsoft Inc, whose general manager wrote a letter to Villanueva. His response received worldwide attention and is seen a
Anders Hejlsberg is a prominent Danish software engineer who co-designed several popular and commercially successful programming languages and development tools. He was the chief architect of Delphi, he works for Microsoft as the lead architect of C# and core developer on TypeScript. Hejlsberg was born in Copenhagen and studied Electrical Engineering at the Technical University of Denmark. While at the university in 1980, he began writing programs for the Nascom microcomputer, including a Pascal compiler, marketed as the Blue Label Software Pascal for the Nascom-2. However, he soon rewrote it for CP/M and DOS, marketing it first as Compas Pascal and as PolyPascal; the product was licensed to Borland, integrated into an IDE to become the Turbo Pascal system. Turbo Pascal competed with PolyPascal; the compiler itself was inspired by the "Tiny Pascal" compiler in Niklaus Wirth's "Algorithms + Data Structures = Programs", one of the most influential computer science books of the time. In Borland's hands, Turbo Pascal became one of the most commercially successful Pascal compilers.
Microsoft doubled the bonus to US$1,000,000. Hejlsberg left Borland in October 1996; the C# Design Process The Trouble with Checked Exceptions Delegates and Simplexity Versioning and Override Contracts and Interoperability Inappropriate Abstractions Generics in C#, Java and C++ CLR Design Choices Microsoft's Hejlsberg touts. NET, C-Omega technologies Deep Inside C#: An Interview with Microsoft Chief Architect Anders Hejlsberg C#: Yesterday and Tomorrow Video interview at channel9 Computerworld Interview with Anders on C# Anders Hejlsberg - Introducing TypeScript Life and Times of Anders Hejlsberg Anders Hejlsberg - Tour through computing industry history at the Microsoft Museum Anders Hejlsberg - What's so great about generics? Anders Hejlsberg - Programming data in C# 3.0 Anders Hejlsberg - What brought about the birth of the CLR Anders Hejlsberg - The. NET Show: The. NET Framework Anders Hejlsberg - The. NET Show: Programming in C# Anders Hejlsberg - More C# Talk from C#'s Architect Anders Hejlsberg - LINQ Anders Hejlsberg - Whiteboard with Anders Hejlsberg Anders Hejlsberg - LINQ and Functional Programming Outstanding Technical Achievement: C# Team Anders Hejlsberg - The Future of C# Anders Hejlsberg - The future of programming languages The Future of C# and Visual Basic
A film called a movie, motion picture, moving picture, or photoplay, is a series of still images that, when shown on a screen, create the illusion of moving images. This optical illusion causes the audience to perceive continuous motion between separate objects viewed in rapid succession; the process of filmmaking is both an industry. A film is created by photographing actual scenes with a motion-picture camera, by photographing drawings or miniature models using traditional animation techniques, by means of CGI and computer animation, or by a combination of some or all of these techniques, other visual effects; the word "cinema", short for cinematography, is used to refer to filmmaking and the film industry, to the art of filmmaking itself. The contemporary definition of cinema is the art of simulating experiences to communicate ideas, perceptions, beauty or atmosphere by the means of recorded or programmed moving images along with other sensory stimulations. Films were recorded onto plastic film through a photochemical process and shown through a movie projector onto a large screen.
Contemporary films are now fully digital through the entire process of production and exhibition, while films recorded in a photochemical form traditionally included an analogous optical soundtrack. Films are cultural artifacts created by specific cultures, they reflect those cultures. Film is considered to be an important art form, a source of popular entertainment, a powerful medium for educating—or indoctrinating—citizens; the visual basis of film gives it a universal power of communication. Some films have become popular worldwide attractions through the use of dubbing or subtitles to translate the dialog into other languages; the individual images that make up a film are called frames. In the projection of traditional celluloid films, a rotating shutter causes intervals of darkness as each frame, in turn, is moved into position to be projected, but the viewer does not notice the interruptions because of an effect known as persistence of vision, whereby the eye retains a visual image for a fraction of a second after its source disappears.
The perception of motion is due to a psychological effect called the phi phenomenon. The name "film" originates from the fact that photographic film has been the medium for recording and displaying motion pictures. Many other terms exist for an individual motion-picture, including picture, picture show, moving picture and flick; the most common term in the United States is movie. Common terms for the field in general include the big screen, the silver screen, the movies, cinema. In early years, the word sheet was sometimes used instead of screen. Preceding film in origin by thousands of years, early plays and dances had elements common to film: scripts, costumes, direction, audiences and scores. Much terminology used in film theory and criticism apply, such as mise en scène. Owing to the lack of any technology for doing so, the moving images and sounds could not be recorded for replaying as with film; the magic lantern created by Christiaan Huygens in the 1650s, could be used to project animation, achieved by various types of mechanical slides.
Two glass slides, one with the stationary part of the picture and the other with the part, to move, would be placed one on top of the other and projected together the moving slide would be hand-operated, either directly or by means of a lever or other mechanism. Chromotrope slides, which produced eye-dazzling displays of continuously cycling abstract geometrical patterns and colors, were operated by means of a small crank and pulley wheel that rotated a glass disc. In the mid-19th century, inventions such as Joseph Plateau's phenakistoscope and the zoetrope demonstrated that a designed sequence of drawings, showing phases of the changing appearance of objects in motion, would appear to show the objects moving if they were displayed one after the other at a sufficiently rapid rate; these devices relied on the phenomenon of persistence of vision to make the display appear continuous though the observer's view was blocked as each drawing rotated into the location where its predecessor had just been glimpsed.
Each sequence was limited to a small number of drawings twelve, so it could only show endlessly repeating cyclical motions. By the late 1880s, the last major device of this type, the praxinoscope, had been elaborated into a form that employed a long coiled band containing hundreds of images painted on glass and used the elements of a magic lantern to project them onto a screen; the use of sequences of photographs in such devices was limited to a few experiments with subjects photographed in a series of poses because the available emulsions were not sensitive enough to allow the short exposures needed to photograph subjects that were moving. The sensitivity was improved and in the late 1870s, Eadweard Muybridge created the first animated image sequences photographed in real-time. A row of cameras was used, each, in turn, capturing one image on a photographic glass plate, so the total number of images in each sequence was limited by the number of cameras, about two dozen at most. Muybridge used his system to analyze the movements of a wi
Wine is a free and open-source compatibility layer that aims to allow computer programs developed for Microsoft Windows to run on Unix-like operating systems. Wine provides a software library, known as Winelib, against which developers can compile Windows applications to help port them to Unix-like systems. Wine provides its own Windows runtime environment which translates Windows system calls into POSIX-compliant system calls, recreating the directory structure of Windows systems, providing alternative implementations of Windows system libraries, system services through wineserver and various other components. Wine is predominantly written using black-box testing reverse-engineering, to avoid copyright issues. Wine Project name being Wine is Not an Emulator was set as of August 1993 in the Naming discussion and credited to David Niemi this is a recursive backronym. There is some confusion caused by an early FAQ using Windows Emulator and other invalid sources that appear after the Wine Project name being set.
No code emulation or virtualization occurs. "Emulation" would refer to execution of compiled code intended for one processor by interpreting/recompiling software running on a different processor. While the name sometimes appears in the forms WINE and wine, the project developers have agreed to standardize on the form Wine. Wine is developed for Linux and macOS, there are well-maintained packages available for both platforms. In a 2007 survey by desktoplinux.com of 38,500 Linux desktop users, 31.5% of respondents reported using Wine to run Windows applications. This plurality was larger than all x86 virtualization programs combined, as well as larger than the 27.9% who reported not running Windows applications. Bob Amstadt, the initial project leader, Eric Youngdale started the Wine project in 1993 as a way to run Windows applications on Linux, it was inspired by two Sun Microsystems' products, the Wabi for the Solaris operating system, the Public Windows Initiative, an attempt to get the Windows API reimplemented in the public domain as an ISO standard but rejected due to pressure from Microsoft in 1996.
Wine targeted 16-bit applications for Windows 3.x, but as of 2010 focuses on 32-bit and 64-bit versions which have become the standard on newer operating systems. The project originated in discussions on Usenet in comp.os.linux in June 1993. Alexandre Julliard has led the project since 1994; the project has proven time-consuming and difficult for the developers because of incomplete and incorrect documentation of the Windows API. While Microsoft extensively documents most Win32 functions, some areas such as file formats and protocols have no publicly available specification from Microsoft, Windows includes undocumented low-level functions, undocumented behavior and obscure bugs that Wine must duplicate in order to allow some applications to work properly; the Wine team has reverse-engineered many function calls and file formats in such areas as thunking. The Wine project released Wine under the same MIT License as the X Window System, but owing to concern about proprietary versions of Wine not contributing their changes back to the core project, work as of March 2002 has used the LGPL for its licensing.
Wine entered beta with version 0.9 on 25 October 2005. Version 1.0 was released on 17 June 2008, after 15 years of development. Version 1.2 was released on 16 July 2010, version 1.4 on 7 March 2012, version 1.6 on 18 July 2013. and version 1.8 on 19 December 2015. Development versions are released every two weeks; the main corporate sponsor of Wine is CodeWeavers, which employs Julliard and many other Wine developers to work on Wine and on CrossOver, CodeWeavers' supported version of Wine. CrossOver includes some application-specific tweaks not considered suitable for the WineHQ version, as well as some additional proprietary components; the involvement of Corel for a time assisted the project, chiefly by employing Julliard and others to work on it. Corel had an interest in porting its office suite, to Linux. Corel cancelled all Linux-related projects after Microsoft made major investments in Corel, stopping their Wine effort. Other corporate sponsors include Google, which hired CodeWeavers to fix Wine so Picasa ran well enough to be ported directly to Linux using the same binary as on Windows.
Wine is a regular beneficiary of Google's Summer of Code program. The goal of Wine is to implement the Windows APIs or that are required by programs that the users of Wine wish to run on top of a Unix-like system; the Win32 function calls are collectively called the Win32 API. DirectX is a collection of APIs for rendering and input. While most office software does not make use of these, computer games do; as of 2017, Wine contains a DirectX 9.0c implementation. In February 2019, a re-implemenation of the XAudio2 audio API was merged into Wine and was released as part of Wine 4.3. Many games which use a Direct3D 9 rendering path can run on top of Wine; the Gallium3D driver model creates. A free and open-source Gallium3D State Tracker was written for Microsoft Direct3D 9 in C. After some modification to Wine, it is now possible to use Direct3D 9 games without the requirement to translate Direct3
Time is an American weekly news magazine and news website published in New York City. It was founded in 1923 and run by Henry Luce. A European edition is published in London and covers the Middle East, and, since 2003, Latin America. An Asian edition is based in Hong Kong; the South Pacific edition, which covers Australia, New Zealand, the Pacific Islands, is based in Sydney. In December 2008, Time discontinued publishing a Canadian advertiser edition. Time has the world's largest circulation for a weekly news magazine; the print edition has a readership of 26 million. In mid-2012, its circulation was over three million, which had lowered to two million by late 2017. Richard Stengel was the managing editor from May 2006 to October 2013, when he joined the U. S. State Department. Nancy Gibbs was the managing editor from September 2013 until September 2017, she was succeeded by Edward Felsenthal, Time's digital editor. Time magazine was created in 1923 by Briton Hadden and Henry Luce, making it the first weekly news magazine in the United States.
The two had worked together as chairman and managing editor of the Yale Daily News. They first called the proposed magazine Facts, they wanted to emphasize brevity. They changed the name to Time and used the slogan "Take Time–It's Brief". Hadden was liked to tease Luce, he saw Time as important, but fun, which accounted for its heavy coverage of celebrities, the entertainment industry, pop culture—criticized as too light for serious news. It set out to tell the news through people, for many decades, the magazine's cover depicted a single person. More Time has incorporated "People of the Year" issues which grew in popularity over the years. Notable mentions of them were Steve Jobs, etc.. The first issue of Time was published on March 3, 1923, featuring Joseph G. Cannon, the retired Speaker of the House of Representatives, on its cover. 1, including all of the articles and advertisements contained in the original, was included with copies of the February 28, 1938 issue as a commemoration of the magazine's 15th anniversary.
The cover price was 15¢ On Hadden's death in 1929, Luce became the dominant man at Time and a major figure in the history of 20th-century media. According to Time Inc.: The Intimate History of a Publishing Enterprise 1972–2004 by Robert Elson, "Roy Edward Larsen was to play a role second only to Luce's in the development of Time Inc". In his book, The March of Time, 1935–1951, Raymond Fielding noted that Larsen was "originally circulation manager and general manager of Time publisher of Life, for many years president of Time Inc. and in the long history of the corporation the most influential and important figure after Luce". Around the time they were raising $100,000 from wealthy Yale alumni such as Henry P. Davison, partner of J. P. Morgan & Co. publicity man Martin Egan and J. P. Morgan & Co. banker Dwight Morrow, Henry Luce, Briton Hadden hired Larsen in 1922 – although Larsen was a Harvard graduate and Luce and Hadden were Yale graduates. After Hadden died in 1929, Larsen purchased 550 shares of Time Inc. using money he obtained from selling RKO stock which he had inherited from his father, the head of the Benjamin Franklin Keith theatre chain in New England.
However, after Briton Hadden's death, the largest Time, Inc. stockholder was Henry Luce, who ruled the media conglomerate in an autocratic fashion, "at his right hand was Larsen", Time's second-largest stockholder, according to Time Inc.: The Intimate History of a Publishing Enterprise 1923–1941. In 1929, Roy Larsen was named a Time Inc. director and vice president. J. P. Morgan retained a certain control through two directorates and a share of stocks, both over Time and Fortune. Other shareholders were the New York Trust Company; the Time Inc. stock owned by Luce at the time of his death was worth about $109 million, it had been yielding him a yearly dividend of more than $2.4 million, according to Curtis Prendergast's The World of Time Inc.: The Intimate History of a Changing Enterprise 1957–1983. The Larsen family's Time stock was worth around $80 million during the 1960s, Roy Larsen was both a Time Inc. director and the chairman of its executive committee serving as Time's vice chairman of the board until the middle of 1979.
According to the September 10, 1979, issue of The New York Times, "Mr. Larsen was the only employee in the company's history given an exemption from its policy of mandatory retirement at age 65." After Time magazine began publishing its weekly issues in March 1923, Roy Larsen was able to increase its circulation by using U. S. radio and movie theaters around the world. It promoted both Time magazine and U. S. political and corporate interests. According to The March of Time, as early as 1924, Larsen had brought Time into the infant radio business with the broadcast of a 15-minute sustaining quiz show entitled Pop Question which survived until 1925". In 1928, Larsen "undertook the weekly broadcast of a 10-minute programme series of brief news summaries, drawn from current issues of Time magazine, broadcast over 33 stations throughout the United States". Larsen next arranged for a 30-minute radio program, The March of Time, to be broadcast over CBS, beginning on March 6, 1931; each week, the program presented a dramatisation of the week's news for its listeners, thus Time magazine itself was brought "to the attention of millions unaware
Richard Matthew Stallman known by his initials, RMS, is an American free software movement activist and programmer. He campaigns for software to be distributed in a manner such that its users receive the freedoms to use, study and modify that software. Software that ensures these freedoms is termed free software. Stallman launched the GNU Project, founded the Free Software Foundation, developed the GNU Compiler Collection and GNU Emacs, wrote the GNU General Public License. Stallman launched the GNU Project in September 1983 to create a Unix-like computer operating system composed of free software. With this, he launched the free software movement, he has been the GNU project's lead architect and organizer, developed a number of pieces of used GNU software including, among others, the GNU Compiler Collection, the GNU Debugger and the GNU Emacs text editor. In October 1985 he founded the Free Software Foundation. Stallman pioneered the concept of copyleft, which uses the principles of copyright law to preserve the right to use and distribute free software, is the main author of free software licenses which describe those terms, most notably the GNU General Public License, the most used free software license.
In 1989, he co-founded the League for Programming Freedom. Since the mid-1990s, Stallman had spent most of his time advocating for free software, as well as campaigning against software patents, digital rights management, other legal and technical systems which he sees as taking away users' freedoms; this has included software license agreements, non-disclosure agreements, activation keys, copy restriction, proprietary formats and binary executables without source code. Stallman was born March 16, 1953 in New York City, to a family of Jewish heritage, though Stallman is an atheist, his parents are Alice Lippman, a school teacher, Daniel Stallman, a printing press broker. Stallman had a difficult relationship with his parents, as his father had a drinking habit and verbally abused his stepmother, he came to describe his parents as "tyrants". He was interested in computers at a young age. From 1967 to 1969, Stallman attended a Columbia University Saturday program for high school students. Stallman was a volunteer laboratory assistant in the biology department at Rockefeller University.
Although he was interested in mathematics and physics, his teaching professor at Rockefeller thought he showed promise as a biologist. His first experience with actual computers was at the IBM New York Scientific Center when he was in high school, he was hired for the summer in 1970, following his senior year of high school, to write a numerical analysis program in Fortran. He completed the task after a couple of weeks and spent the rest of the summer writing a text editor in APL and a preprocessor for the PL/I programming language on the IBM System/360; as a first-year student at Harvard University in fall 1970, Stallman was known for his strong performance in Math 55. He was happy: "For the first time in my life, I felt I had found a home at Harvard."In 1971, near the end of his first year at Harvard, he became a programmer at the MIT Artificial Intelligence Laboratory, became a regular in the hacker community, where he was known by his initials, RMS. Stallman received a bachelor's degree in physics from Harvard in 1974.
Stallman considered staying on at Harvard, but instead he decided to enroll as a graduate student at the Massachusetts Institute of Technology. He pursued a doctorate in physics for one year, but left that program to focus on his programming at the MIT AI Laboratory. While working as a research assistant at MIT under Gerry Sussman, Stallman published a paper in 1977 on an AI truth maintenance system, called dependency-directed backtracking; this paper was an early work on the problem of intelligent backtracking in constraint satisfaction problems. As of 2009, the technique Stallman and Sussman introduced is still the most general and powerful form of intelligent backtracking; the technique of constraint recording, wherein partial results of a search are recorded for reuse, was introduced in this paper. As a hacker in MIT's AI laboratory, Stallman worked on software projects such as TECO, Emacs for ITS, the Lisp machine operating system, he would become an ardent critic of restricted computer access in the lab, which at that time was funded by the Defense Advanced Research Projects Agency.
When MIT's Laboratory for Computer Science installed a password control system in 1977, Stallman found a way to decrypt the passwords and sent users messages containing their decoded password, with a suggestion to change it to the empty string instead, to re-enable anonymous access to the systems. Around 20 percent of the users followed his advice at the time, although passwords prevailed. Stallman boasted of the success of his campaign for many years afterward. In the late 1970s and early 1980s, the hacker culture that Stallman thrived on began to fragment. To prevent software from being used on their competitors' computers, most manufacturers stopped distributing source code and began using copyright and restrictive software licenses to limit or prohibit copying and redistribution. Such