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.
A chapbook is a type of street literature printed in early modern Europe. Produced cheaply, chapbooks were small, paper-covered booklets printed on a single sheet folded into books of 8, 12, 16 and 24 pages, they were illustrated with crude woodcuts, which sometimes bore no relation to the text. When illustrations were included in chapbooks, they were considered popular prints; the tradition of chapbooks arose in the 16th century, as soon as printed books became affordable, rose to its height during the 17th and 18th centuries. Many different kinds of ephemera and popular or folk literature were published as chapbooks, such as almanacs, children's literature, folk tales, nursery rhymes, pamphlets and political and religious tracts; the term "chapbook" for this type of literature was coined in the 19th century. The corresponding French and German terms are bibliothèque bleue and Volksbuch, respectively. In Spain they were known as pliegos de cordel; the term "chapbook" is in use for present-day publications short, inexpensive booklets.
Chapbook is first attested in English in 1824, seems to derive from the word for the itinerant salesmen who would sell such books: chapman. The first element of chapman comes in turn from Old English cēap. Broadside ballads were popular songs, sold for a penny or halfpenny in the streets of towns and villages around Britain between the 16th century and early 20th centuries, they preceded chapbooks, but had similar content and distribution systems. There are records from Cambridgeshire as early as in 1553 of a man offering a scurrilous ballad "maistres mass" at an alehouse, a pedlar selling "lytle books" to people, including a patcher of old clothes in 1578; these sales are characteristic of the market for chapbooks. Chapbooks disappeared from the mid-19th century in the face of competition from cheap newspapers and in Scotland, religious tract societies that regarded them as "ungodly." Although the form originated in Britain, many were made in the U. S. during the same period. Because of their flimsy nature such ephemera survive as individual items.
They were aimed at buyers without formal libraries, and, in an era when paper was expensive, were used for wrapping or baking. Paper has always had hygienic uses. Many of the surviving chapbooks come from the collections of Samuel Pepys between 1661 and 1688 which are now held at Magdalene College, Cambridge; the antiquary Anthony Wood collected 65 chapbooks, which are now in the Bodleian Library. There are significant Scottish collections, such as those held by the University of Glasgow. Modern collectors, such as Peter Opie, have chiefly a scholarly interest in the form. Chapbooks were cheap, anonymous publications that were the usual reading material for lower-class people who could not afford books. Members of the upper classes owned chapbooks bound in leather with a personal monogram. Printers tailored their texts for the popular market. Chapbooks were between four and twenty-four pages long, produced on rough paper with crude recycled, woodcut illustrations, they sold in the millions. After 1696 English chapbook peddlers had to be licensed, 2,500 of them were authorized, 500 in London alone.
In France, there were 3,500 licensed colporteurs by 1848, they sold 40 million books annually. The centre of chapbook and ballad production was London, until the Great Fire of London the printers were based around London Bridge. However, a feature of chapbooks is the proliferation of provincial printers in Scotland and Newcastle upon Tyne. Chapbooks were an important medium for the dissemination of popular culture to the common people in rural areas, they were a medium of entertainment and history. In general, the content of chapbooks has been criticized, for their unsophisticated narratives which were loaded with repetition and emphasized adventure through anecdotal structures. However, they are nonetheless valued as a record of popular culture, preserving cultural artifacts that may not survive in any other form. Chapbooks were priced for sales to workers, although their market was not limited to the working classes. Broadside ballads were sold for a few pence. Prices of chapbooks were from 2d. to 6d.
When agricultural labourers wages were 12d. per day. The literacy rate in England in the 1640s was around 30 percent for males and rose to 60 percent in the mid-18th century. Many working people were readers, if not writers, pre-industrial working patterns provided periods during which they could read. Chapbooks were undoubtedly used for reading to family groups in alehouses, they contributed to the development of literacy. The author and publisher Francis Kirkman wrote about how they fired his imagination and his love of books. There is other evidence of their use by autodidacts; the numbers printed are astonishing. In the 1660s as many as 400,000 almanacs were printed annually, enough for one family in three in England. One 17th-century publisher of chapbooks in London had in stock one book for every 15 families in the country. In the 1520s the Oxford bookseller, John Dorne, noted in his day-book selling up to 190 ballads a day at a halfpenny each; the probate inventory of the stock of Charles Tias, of The sign of the Three Bibles on London Bridge, in 1664 included books and printed sheets to make c.90,000 chapbooks and 37,500 ballad sheets.
Lisp machines are general-purpose computers designed to efficiently run Lisp as their main software and programming language via hardware support. They are an example of a high-level language computer architecture, in a sense, they were the first commercial single-user workstations. Despite being modest in number, Lisp machines commercially pioneered many now-commonplace technologies, including effective garbage collection, laser printing, windowing systems, computer mice, high-resolution bit-mapped raster graphics, computer graphic rendering, networking innovations such as Chaosnet. Several firms built and sold Lisp machines in the 1980s: Symbolics, Lisp Machines Incorporated, Texas Instruments, Xerox; the operating systems were written in Lisp Machine Lisp and partly in Common Lisp. Artificial intelligence computer programs of the 1960s and 1970s intrinsically required what was considered a huge amount of computer power, as measured in processor time and memory space; the power requirements of AI research were exacerbated by the Lisp symbolic programming language, when commercial hardware was designed and optimized for assembly- and Fortran-like programming languages.
At first, the cost of such computer hardware meant. As integrated circuit technology shrank the size and cost of computers in the 1960s and early 1970s, the memory needs of AI programs began to exceed the address space of the most common research computer, the DEC PDP-10, researchers considered a new approach: a computer designed to develop and run large artificial intelligence programs, tailored to the semantics of the Lisp language. To keep the operating system simple, these machines would not be shared, but would be dedicated to single users. In 1973, Richard Greenblatt and Thomas Knight, programmers at Massachusetts Institute of Technology Artificial Intelligence Laboratory, began what would become the MIT Lisp Machine Project when they first began building a computer hardwired to run certain basic Lisp operations, rather than run them in software, in a 24-bit tagged architecture; the machine did incremental garbage collection. More since Lisp variables are typed at runtime rather than compile time, a simple addition of two variables could take five times as long on conventional hardware, due to test and branch instructions.
Lisp Machines ran the tests in parallel with the more conventional single instruction additions. If the simultaneous tests failed the result was discarded and recomputed; this simultaneous checking approach was used as well in testing the bounds of arrays when referenced, other memory management necessities. Type checking was further improved and automated when the conventional byte word of 32-bits was lengthened to 36-bits for Symbolics 3600-model Lisp machines and to 40-bits or more; the first group of extra bits were used to hold type data, making the machine a tagged architecture, the remaining bits were used to implement CDR coding, aiding garbage collection by an order of magnitude. A further improvement was two microcode instructions which supported Lisp functions, reducing the cost of calling a function to as little as 20 clock cycles, in some Symbolics implementations; the first machine was called the CONS machine. It was affectionately referred to as the Knight machine since Knight wrote his master's thesis on the subject.
It was subsequently improved into a version called CADR, based on the same architecture. About 25 of what were prototype CADRs were sold within and without MIT for ~$50,000, it was so well received at an AI conference held at MIT in 1978 that Defense Advanced Research Projects Agency began funding its development. In 1979, Russell Noftsker, being convinced that Lisp machines had a bright commercial future due to the strength of the Lisp language and the enabling factor of hardware acceleration, proposed to Greenblatt that they commercialize the technology. In a counter-intuitive move for an AI Lab hacker, Greenblatt acquiesced, hoping that he could recreate the informal and productive atmosphere of the Lab in a real business; these ideas and goals were different from those of Noftsker. The two negotiated at length; as the proposed firm could succeed only with the full and undivided assistance of the AI Lab hackers as a group and Greenblatt decided that the fate of the enterprise was up to them, so the choice should be left to the hackers.
The ensuing discussions of the choice divided the lab into two factions. In February 1979, matters came to a head; the hackers sided with Noftsker, believing that a commercial venture fund-backed firm had a better chance of surviving and commercializing Lisp machines than Greenblatt's proposed self-sustaining start-up. Greenblatt lost the battle, it was at th
Computer science is the study of processes that interact with data and that can be represented as data in the form of programs. It enables the use of algorithms to manipulate and communicate digital information. A computer scientist studies the theory of computation and the practice of designing software systems, its fields can be divided into practical disciplines. Computational complexity theory is abstract, while computer graphics emphasizes real-world applications. Programming language theory considers approaches to the description of computational processes, while computer programming itself involves the use of programming languages and complex systems. Human–computer interaction considers the challenges in making computers useful and accessible; the earliest foundations of what would become computer science predate the invention of the modern digital computer. Machines for calculating fixed numerical tasks such as the abacus have existed since antiquity, aiding in computations such as multiplication and division.
Algorithms for performing computations have existed since antiquity before the development of sophisticated computing equipment. Wilhelm Schickard designed and constructed the first working mechanical calculator in 1623. In 1673, Gottfried Leibniz demonstrated a digital mechanical calculator, called the Stepped Reckoner, he may be considered the first computer scientist and information theorist, among other reasons, documenting the binary number system. In 1820, Thomas de Colmar launched the mechanical calculator industry when he released his simplified arithmometer, the first calculating machine strong enough and reliable enough to be used daily in an office environment. Charles Babbage started the design of the first automatic mechanical calculator, his Difference Engine, in 1822, which gave him the idea of the first programmable mechanical calculator, his Analytical Engine, he started developing this machine in 1834, "in less than two years, he had sketched out many of the salient features of the modern computer".
"A crucial step was the adoption of a punched card system derived from the Jacquard loom" making it infinitely programmable. In 1843, during the translation of a French article on the Analytical Engine, Ada Lovelace wrote, in one of the many notes she included, an algorithm to compute the Bernoulli numbers, considered to be the first computer program. Around 1885, Herman Hollerith invented the tabulator, which used punched cards to process statistical information. In 1937, one hundred years after Babbage's impossible dream, Howard Aiken convinced IBM, making all kinds of punched card equipment and was in the calculator business to develop his giant programmable calculator, the ASCC/Harvard Mark I, based on Babbage's Analytical Engine, which itself used cards and a central computing unit; when the machine was finished, some hailed it as "Babbage's dream come true". During the 1940s, as new and more powerful computing machines were developed, the term computer came to refer to the machines rather than their human predecessors.
As it became clear that computers could be used for more than just mathematical calculations, the field of computer science broadened to study computation in general. In 1945, IBM founded the Watson Scientific Computing Laboratory at Columbia University in New York City; the renovated fraternity house on Manhattan's West Side was IBM's first laboratory devoted to pure science. The lab is the forerunner of IBM's Research Division, which today operates research facilities around the world; the close relationship between IBM and the university was instrumental in the emergence of a new scientific discipline, with Columbia offering one of the first academic-credit courses in computer science in 1946. Computer science began to be established as a distinct academic discipline in the 1950s and early 1960s; the world's first computer science degree program, the Cambridge Diploma in Computer Science, began at the University of Cambridge Computer Laboratory in 1953. The first computer science degree program in the United States was formed at Purdue University in 1962.
Since practical computers became available, many applications of computing have become distinct areas of study in their own rights. Although many believed it was impossible that computers themselves could be a scientific field of study, in the late fifties it became accepted among the greater academic population, it is the now well-known IBM brand that formed part of the computer science revolution during this time. IBM released the IBM 704 and the IBM 709 computers, which were used during the exploration period of such devices. "Still, working with the IBM was frustrating if you had misplaced as much as one letter in one instruction, the program would crash, you would have to start the whole process over again". During the late 1950s, the computer science discipline was much in its developmental stages, such issues were commonplace. Time has seen significant improvements in the effectiveness of computing technology. Modern society has seen a significant shift in the users of computer technology, from usage only by experts and professionals, to a near-ubiquitous user base.
Computers were quite costly, some degree of humanitarian aid was needed for efficient use—in part from professional computer operators. As computer adoption became more widespread and affordable, less human assistance was needed for common usage. Despite its short history as a formal academic discipline, computer science has made a number of fundamental contributions to science and society—in fact, along with electronics, it is
Emacs or EMACS is a family of text editors that are characterized by their extensibility. The manual for the most used variant, GNU Emacs, describes it as "the extensible, self-documenting, real-time display editor". Development of the first Emacs began in the mid-1970s, work on its direct descendant, GNU Emacs, continues as of 2019. Emacs has over 10,000 built-in commands and its user interface allows the user to combine these commands into macros to automate work. Implementations of Emacs feature a dialect of the Lisp programming language that provides a deep extension capability, allowing users and developers to write new commands and applications for the editor. Extensions have been written to manage email, outlines, RSS feeds, as well as clones of ELIZA, Conway's Life and Tetris; the original EMACS was written in 1976 by Carl Mikkelsen, David A. Moon and Guy L. Steele Jr. as a set of Editor MACroS for the TECO editor. It was inspired by the ideas of the TECO-macro editors TECMAC and TMACS.
The most popular, most ported, version of Emacs is GNU Emacs, created by Richard Stallman for the GNU Project. XEmacs is a variant that branched from GNU Emacs in 1991. GNU Emacs and XEmacs are for the most part compatible with each other. Emacs is, along with vi, one of the two main contenders in the traditional editor wars of Unix culture. Emacs is among the open source projects still under development. Emacs development began during the 1970s at the MIT AI Lab, whose PDP-6 and PDP-10 computers used the Incompatible Timesharing System operating system that featured a default line editor known as Tape Editor and Corrector. Unlike most modern text editors, TECO used separate modes in which the user would either add text, edit existing text, or display the document. One could not place characters directly into a document by typing them into TECO, but would instead enter a character in the TECO command language telling it to switch to input mode, enter the required characters, during which time the edited text was not displayed on the screen, enter a character to switch the editor back to command mode.
This behavior is similar to that of the program ed. Richard Stallman visited the Stanford AI Lab in 1972 or 1974 and saw the lab's E editor, written by Fred Wright, he was impressed by the editor's intuitive WYSIWYG behavior, which has since become the default behavior of most modern text editors. He returned to MIT where Carl Mikkelsen, a hacker at the AI Lab, had added to TECO a combined display/editing mode called Control-R that allowed the screen display to be updated each time the user entered a keystroke. Stallman reimplemented this mode to run efficiently and added a macro feature to the TECO display-editing mode that allowed the user to redefine any keystroke to run a TECO program. E had another feature: random-access editing. TECO was a page-sequential editor, designed for editing paper tape on the PDP-1 and allowed editing on only one page at a time, in the order of the pages in the file. Instead of adopting E's approach of structuring the file for page-random access on disk, Stallman modified TECO to handle large buffers more efficiently and changed its file-management method to read and write the entire file as a single buffer.
All modern editors use this approach. The new version of TECO became popular at the AI Lab and soon accumulated a large collection of custom macros whose names ended in MAC or MACS, which stood for macro. Two years Guy Steele took on the project of unifying the diverse macros into a single set. Steele and Stallman's finished implementation included facilities for extending and documenting the new macro set; the resulting system was called EMACS, which stood for Editing MACroS or, alternatively, E with MACroS. Stallman picked the name Emacs "because <E> was not in use as an abbreviation on ITS at the time." An apocryphal hacker koan alleges that the program was named after Emack & Bolio's, a popular Cambridge ice cream store. The first operational EMACS system existed in late 1976. Stallman saw a problem in too much customization and de facto forking and set certain conditions for usage, he wrote: "EMACS was distributed on a basis of communal sharing, which means all improvements must be given back to me to be incorporated and distributed."The original Emacs, like TECO, ran only on the PDP-10 running ITS.
Its behavior was sufficiently different from that of TECO that it could be considered a text editor in its own right, it became the standard editing program on ITS. Mike McMahon ported Emacs from ITS to the TOPS-20 operating systems. Other contributors to early versions of Emacs include Kent Pitman, Earl Killian, Eugene Ciccarelli. By 1979, Emacs was the main editor used in its Laboratory for Computer Science. In the following years, programmers wrote a variety of Emacs-like editors for other computer systems; these included EINE and ZWEI, which were written for the Lisp machine by Mike McMahon and Daniel Weinreb, Sine, written by Owen Theodore Anderson. Weinreb's EINE was the first Emacs written in Lisp. In 1978, Bernard Greenberg wrote Multics Emacs entirely in Multics Lisp at Honeywell's Cambridge Information Systems Lab. Multics Emacs was maintained by Richard Soley, who went on to develop the NILE Emacs-like editor for the NIL Project, by Barry Margolin. Many versions of Emacs, including GNU Emacs, would adopt Lisp as an extension language.
James Gosling, who would invent Ne
University of Illinois at Urbana–Champaign
The University of Illinois at Urbana–Champaign is a public research university in Illinois and the flagship institution of the University of Illinois System. Founded in 1867 as a land-grant institution, its campus is located in the twin cities of Champaign and Urbana; the University of Illinois at Urbana–Champaign is a member of the Association of American Universities and is classified as a R1 Doctoral Research University under the Carnegie Classification of Institutions of Higher Education, which denotes the highest research activity. In fiscal year 2017, research expenditures at Illinois totaled $642 million; the campus library system possesses the second-largest university library in the United States by holdings after Harvard University. The university hosts the National Center for Supercomputing Applications and is home to the fastest supercomputer on a university campus; the university contains 16 schools and colleges and offers more than 150 undergraduate and over 100 graduate programs of study.
The university holds 651 buildings on 6,370 acres and its annual operating budget in 2016 was over $2 billion. The University of Illinois at Urbana–Champaign operates a Research Park home to innovation centers for over 90 start-up companies and multinational corporations, including Abbott, AbbVie, Capital One, State Farm, Yahoo, among others; as of October 2018, 30 Nobel laureates, 2 Turing Award winners, 1 Fields medalist have been affiliated with the university as alumni, faculty members, or researchers. The University of Illinois named "Illinois Industrial University", was one of the 37 universities created under the first Morrill Land-Grant Act, which provided public land for the creation of agricultural and industrial colleges and universities across the United States. Among several cities, Urbana was selected in 1867 as the site for the new school. From the beginning, President John Milton Gregory's desire to establish an institution grounded in the liberal arts tradition was at odds with many state residents and lawmakers who wanted the university to offer classes based around "industrial education".
The university opened for classes on March 2, 1868, had two faculty members and 77 students. The Library, which opened with the school in 1868, started with 1,039 volumes. Subsequently, President Edmund J. James, in a speech to the board of trustees in 1912, proposed to create a research library, it is now one of the world's largest public academic collections. In 1870, the Mumford House was constructed as a model farmhouse for the school's experimental farm; the Mumford House remains the oldest structure on campus. The original University Hall was the fourth building built. In 1885, the Illinois Industrial University changed its name to the "University of Illinois", reflecting its agricultural and liberal arts curriculum. During his presidency, Edmund J. James is credited for building the foundation for the large Chinese international student population on campus. James established ties with China through the Chinese Minister to the United States Wu Ting-Fang. In addition, during James's presidency, class rivalries and Bob Zuppke's winning football teams contributed to campus morale.
Alma Mater, a prominent statue on campus created by alumnus Lorado Taft, was unveiled on June 11, 1929. It was established from donations by the Alumni Fund and the classes of 1923–1929. Like many Universities, the economic depression slowed expansion on the campus; the university replaced the original university hall with the Illini Union. After World War II, the university experienced rapid growth; the enrollment doubled and the academic standing improved. This period was marked by large growth in the Graduate College and increased federal support of scientific and technological research. During the 1950s and 1960s the university experienced the turmoil common on many American campuses. Among these were the water fights of the fifties and sixties. By 1967 the University of Illinois system consisted of a main campus in Champaign-Urbana and two Chicago campuses, Chicago Circle and Medical Center, people began using "Urbana–Champaign" or the reverse to refer to the main campus specifically; the university name changed to the "University of Illinois at Urbana–Champaign" around 1982, using the reverse of the used designation for the metropolitan area, "Champaign-Urbana".
The name change established a separate identity for the main campus within the University of Illinois system, which today includes campuses in Springfield and Chicago. In 1998, the Hallene Gateway Plaza was dedicated; the Plaza features the original sandstone portal of University Hall, the fourth building on campus. In recent years, state support has declined from 4.5% of the state's tax appropriations in 1980 to 2.28% in 2011, a nearly 50% decline. As a result, the university's budget has shifted away from relying on state support with nearly 84% of the budget now coming from other sources. On March 12, 2015, the Board of Trustees approved the creation of a medical school, being the first college created at Urbana–Champaign in over 60 years; the Carle-Illinois College of Medicine began classes in 2018. The main research and academic facilities are divided evenly between the twin cities of Urbana and Champaign, which form part of the Champaign–Urbana metropolitan area; the College of Agriculture and Environmental Sciences' research fields stretch south from Urbana and Champaign into Savoy and Champaign County.
Reduced instruction set computer
A reduced instruction set computer, or RISC, is one whose instruction set architecture allows it to have fewer cycles per instruction than a complex instruction set computer. Various suggestions have been made regarding a precise definition of RISC, but the general concept is that such a computer has a small set of simple and general instructions, rather than a large set of complex and specialized instructions. Another common RISC trait is their load/store architecture, in which memory is accessed through specific instructions rather than as a part of most instructions. Although a number of computers from the 1960s and'70s have been identified as forerunners of RISCs, the modern concept dates to the 1980s. In particular, two projects at Stanford University and the University of California, Berkeley are most associated with the popularization of this concept. Stanford's MIPS would go on to be commercialized as the successful MIPS architecture, while Berkeley's RISC gave its name to the entire concept and was commercialized as the SPARC.
Another success from this era was IBM's effort that led to the IBM POWER instruction set architecture, PowerPC, Power ISA. As these projects matured, a wide variety of similar designs flourished in the late 1980s and the early 1990s, representing a major force in the Unix workstation market as well as for embedded processors in laser printers and similar products; the many varieties of RISC designs include ARC, Alpha, Am29000, ARM, Atmel AVR, Blackfin, i860, i960, M88000, MIPS, PA-RISC, Power ISA, RISC-V, SuperH, SPARC. In the 21st century, the use of ARM architecture processors in smartphones and tablet computers such as the iPad and Android devices provided a wide user base for RISC-based systems. RISC processors are used in supercomputers such as Summit, which, as of November 2018, is the world's fastest supercomputer as ranked by the TOP500 project. Alan Turing's 1946 Automatic Computing Engine design had many of the characteristics of a RISC architecture. A number of systems, going back to the 1960s, have been credited as the first RISC architecture based on their use of load/store approach.
The term RISC was coined by David Patterson of the Berkeley RISC project, although somewhat similar concepts had appeared before. The CDC 6600 designed by Seymour Cray in 1964 used a load/store architecture with only two addressing modes and 74 operation codes, with the basic clock cycle being 10 times faster than the memory access time. Due to the optimized load/store architecture of the CDC 6600, Jack Dongarra says that it can be considered a forerunner of modern RISC systems, although a number of other technical barriers needed to be overcome for the development of a modern RISC system. Michael J. Flynn views the first RISC system as the IBM 801 design, which began in 1975 by John Cocke and was completed in 1980; the 801 was produced in a single-chip form as the IBM ROMP in 1981, which stood for'Research OPD Micro Processor'. As the name implies, this CPU was designed for "mini" tasks, was used in the IBM RT PC in 1986, which turned out to be a commercial failure, but the 801 inspired several research projects, including new ones at IBM that would lead to the IBM POWER instruction set architecture.
The most public RISC designs, were the results of university research programs run with funding from the DARPA VLSI Program. The VLSI Program unknown today, led to a huge number of advances in chip design and computer graphics; the Berkeley RISC project started in 1980 under the direction of David Patterson and Carlo H. Sequin. Berkeley RISC was based on gaining performance through the use of pipelining and an aggressive use of a technique known as register windowing. In a traditional CPU, one has a small number of registers, a program can use any register at any time. In a CPU with register windows, there are a huge number of registers, e.g. 128, but programs can only use a small number of them, e.g. eight, at any one time. A program that limits itself to eight registers per procedure can make fast procedure calls: The call moves the window "down" by eight, to the set of eight registers used by that procedure, the return moves the window back; the Berkeley RISC project delivered the RISC-I processor in 1982.
Consisting of only 44,420 transistors RISC-I had only 32 instructions, yet outperformed any other single-chip design. They followed this up with the 40,760 transistor, 39 instruction RISC-II in 1983, which ran over three times as fast as RISC-I; the MIPS project grew out of a graduate course by John L. Hennessy at Stanford University in 1981, resulted in a functioning system in 1983, could run simple programs by 1984; the MIPS approach emphasized an aggressive clock cycle and the use of the pipeline, making sure it could be run as "full" as possible. The MIPS system was followed by the MIPS-X and in 1984 Hennessy and his colleagues formed MIPS Computer Systems; the commercial venture resulted in a new architecture, called MIPS and the R2000 microprocessor in 1985. In the early 1980s, significant uncertainties surrounded the RISC concept, it was uncertain if it could have a commercial future, but by the mid-1980s the concepts had matured enough to be seen as commercially viable. In 1986 Hewlett Packard started using an early implementation of their PA-RISC in some of their computers.
In the meantime, the Berkeley RISC effort had become so well known that it became the name for the entire concept and in 1987 Sun Microsystems began shipping systems with the SPARC processor