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Computer programming or coding is the composition of sequences of instructions, called programs, that computers can follow to perform tasks. It involves designing and implementing algorithms, step-by-step specifications of procedures, by writing code in one or more programming languages. Programmers typically use high-level programming languages that are more easily intelligible to humans than machine code, which is directly executed by the central processing unit. Proficient programming usually requires expertise in several different subjects, including knowledge of the application domain, details of programming languages and generic code libraries, specialized algorithms, and formal logic.
Auxiliary tasks accompanying and related to programming include analyzing requirements, testing, debugging (investigating and fixing problems), implementation of build systems, and management of derived artifacts, such as programs' machine code. While these are sometimes considered programming, often the term software development is used for this larger overall process – with the terms programming, implementation, and coding reserved for the writing and editing of code per se. Sometimes software development is known as software engineering, especially when it employs formal methods or follows an engineering design process. (Full article...)
In SQL, null or NULL is a special marker used to indicate that a data value does not exist in the database. Introduced by the creator of the relational database model, E. F. Codd, SQL null serves to fulfill the requirement that all true relational database management systems (RDBMS) support a representation of "missing information and inapplicable information". Codd also introduced the use of the lowercase Greek omega (ω) symbol to represent null in database theory. In SQL, NULL is a reserved word used to identify this marker.
A null should not be confused with a value of 0. A null indicates a lack of a value, which is not the same as a zero value. For example, consider the question "How many books does Adam own?" The answer may be "zero" (we know that he owns none) or "null" (we do not know how many he owns). In a database table, the column reporting this answer would start with no value (marked by null), and it would not be updated with the value zero until it is ascertained that Adam owns no books.
In SQL, null is a marker, not a value. This usage is quite different from most programming languages, where a null value of a reference means it is not pointing to any object. (Full article...)
(February 24, 1955 – October 5, 2011) was an American businessman, inventor, and investor best known for co-founding the technology company
Apple Inc.Jobs was also the founder of
NeXTand chairman and majority shareholder of
Pixar. He was a pioneer of the
personal computer revolutionof the 1970s and 1980s, along with his early business partner and fellow Apple co-founder
Steve Wozniak.
Jobs was born in San Francisco in 1955 and adopted shortly afterwards. He attended Reed College in 1972 before withdrawing that same year. In 1974, he traveled through India, seeking enlightenment before later studying Zen Buddhism. He and Wozniak co-founded Apple in 1976 to further develop and sell Wozniak's Apple I personal computer. Together, the duo gained fame and wealth a year later with production and sale of the Apple II, one of the first highly successful mass-produced microcomputers.
Jobs saw the commercial potential of the Xerox Alto in 1979, which was mouse-driven and had a graphical user interface (GUI). This led to the development of the largely unsuccessful Apple Lisa in 1983, followed by the breakthrough Macintosh in 1984, the first mass-produced computer with a GUI. The Macintosh launched the desktop publishing industry in 1985 (for example, the Aldus Pagemaker) with the addition of the Apple LaserWriter, the first laser printer to feature vector graphics and PostScript. (Full article...)
is an extension to the programming language
Pascalthat provides
object-oriented programming(OOP) features such as
classesand
methods.
The language was originally developed by Apple Computer as Clascal for the Lisa Workshop development system. As Lisa gave way to Macintosh, Apple collaborated with Niklaus Wirth, the author of Pascal, to develop an officially standardized version of Clascal. This was renamed Object Pascal. Through the mid-1980s, Object Pascal was the main programming language for early versions of the MacApp application framework. The language lost its place as the main development language on the Mac in 1991 with the release of the C++-based MacApp 3.0. Official support ended in 1996.
Symantec also developed a compiler for Object Pascal for their Think Pascal product, which could compile programs much faster than Apple's own Macintosh Programmer's Workshop (MPW). Symantec then developed the Think Class Library (TCL), based on MacApp concepts, which could be called from both Object Pascal and THINK C. The Think suite largely displaced MPW as the main development platform on the Mac in the late 1980s. (Full article...)
is an
object-oriented programming languagedesigned by
Bertrand Meyer(an object-orientation proponent and author of
Object-Oriented Software Construction) and Eiffel Software. Meyer conceived the language in 1985 with the goal of increasing the reliability of commercial software development. The first version was released in 1986. In 2005, the
International Organization for Standardization(ISO) released a
technical standardfor Eiffel.
The design of the language is closely connected with the Eiffel programming method. Both are based on a set of principles, including design by contract, command–query separation, the uniform-access principle, the single-choice principle, the open–closed principle, and option–operand separation.
Many concepts initially introduced by Eiffel were later added into Java, C#, and other languages. New language design ideas, particularly through the Ecma/ISO standardization process, continue to be incorporated into the Eiffel language. (Full article...)
Typical
secondary outputfrom an assembler—showing original assembly language (right) for the
Motorola MC6800and the assembled form
In computing,
assembly language(alternatively
assembler languageor
symbolic machine code), often referred to simply as
assemblyand commonly abbreviated as
ASMor
asm, is any
low-level programming languagewith a very strong correspondence between the instructions in the language and the
architecture's machine code instructions. Assembly language usually has one
statementper machine instruction (1:1), but constants,
comments, assembler
directives, symbolic
labelsof, e.g.,
memory locations,
registers, and
macrosare generally also supported.
The first assembly code in which a language is used to represent machine code instructions is found in Kathleen and Andrew Donald Booth's 1947 work, Coding for A.R.C.. Assembly code is converted into executable machine code by a utility program referred to as an assembler. The term "assembler" is generally attributed to Wilkes, Wheeler and Gill in their 1951 book The Preparation of Programs for an Electronic Digital Computer, who, however, used the term to mean "a program that assembles another program consisting of several sections into a single program". The conversion process is referred to as assembly, as in assembling the source code. The computational step when an assembler is processing a program is called assembly time.
Because assembly depends on the machine code instructions, each assembly language is specific to a particular computer architecture. (Full article...)
(
; born August 11, 1950), also known by his nickname
Woz, is an American technology entrepreneur,
electrical engineer,
computer programmer, philanthropist, and inventor. In 1976, he co-founded
Apple Computerwith his early business partner
Steve Jobs. Through his work at Apple in the 1970s and 1980s, he is widely recognized as one of the most prominent pioneers of the
personal computer revolution.
In 1975, Wozniak started developing the Apple I into the computer that launched Apple when he and Jobs first began marketing it the following year. He was the primary designer of the Apple II, introduced in 1977, known as one of the first highly successful mass-produced microcomputers, while Jobs oversaw the development of its foam-molded plastic case and early Apple employee Rod Holt developed its switching power supply.
With human–computer interface expert Jef Raskin, Wozniak had a major influence over the initial development of the original Macintosh concepts from 1979 to 1981, when Jobs took over the project following Wozniak's brief departure from the company due to a traumatic airplane accident. After permanently leaving Apple in 1985, Wozniak founded CL 9 and created the first programmable universal remote, released in 1987. He then pursued several other businesses and philanthropic ventures throughout his career, focusing largely on technology in K–12 schools. (Full article...)
(January 21, 1953 – October 15, 2018) was an American businessman, computer programmer, and investor. He co-founded
Microsoft Corporationwith his childhood friend
Bill Gatesin 1975, which was followed by the
microcomputer revolutionof the 1970s and 1980s. Allen was ranked as one of the richest person in American history by
Forbeswith an estimated net worth of $20.3 billion at the time of his death in October 2018.
Allen quit from day-to-day work at Microsoft in early 1983 after a Hodgkin lymphoma diagnosis, remaining on its board as vice-chairman. He and his sister, Jody Allen, founded Vulcan Inc. in 1986, a privately held company that managed his business and philanthropic efforts. At the time of his death, he had a multi-billion dollar investment portfolio, including technology and media companies, scientific research, real estate holdings, private space flight ventures, and stakes in other sectors. He owned the Seattle Seahawks of the National Football League and the Portland Trail Blazers of the National Basketball Association, and was part-owner of the Seattle Sounders FC of Major League Soccer. Under Allen's helm, the Seahawks won Super Bowl XLVIII and made it to two other Super Bowls (XL and XLIX). In 2000 he resigned from his position on Microsoft's board and assumed the post of senior strategy advisor to the company's management team.
Allen founded the Allen Institutes for Brain Science, Artificial Intelligence, and Cell Science, as well as companies like Stratolaunch Systems and Apex Learning. He gave more than $2 billion to causes such as education, wildlife and environmental conservation, the arts, healthcare, and community services. In 2004, he funded the first crewed private spaceplane with SpaceShipOne. He received numerous awards and honors, and was listed among the Time 100 Most Influential People in the World in 2007 and 2008. (Full article...)
is a
general-purpose programming language. It was designed with an emphasis on programming productivity and simplicity. In Ruby, everything is an
object, including
primitive data types. It was developed in the mid-1990s by
Yukihiro "Matz" Matsumotoin
Japan.
Ruby is interpreted, high-level, and dynamically typed; its interpreter uses garbage collection and just-in-time compilation. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming. According to the creator, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, BASIC, and Lisp. (Full article...)
(
; an
acronymfor "common business-oriented language") is a
compiledEnglish-like
computer programming languagedesigned for business use. It is an
imperative,
procedural, and, since 2002,
object-orientedlanguage. COBOL is primarily used in business, finance, and administrative systems for companies and governments. COBOL is still widely used in applications deployed on
mainframe computers, such as large-scale
batchand
transaction processingjobs. Many large financial institutions were developing new systems in the language as late as 2006, but most programming in COBOL today is purely to maintain existing applications. Programs are being moved to new platforms, rewritten in modern languages, or replaced with other software.
COBOL was designed in 1959 by CODASYL and was partly based on the programming language FLOW-MATIC, designed by Grace Hopper. It was created as part of a U.S. Department of Defense effort to create a portable programming language for data processing. It was originally seen as a stopgap, but the Defense Department promptly pressured computer manufacturers to provide it, resulting in its widespread adoption. It was standardized in 1968 and has been revised five times. Expansions include support for structured and object-oriented programming. The current standard is ISO/IEC 1989:2023.
COBOL statements have prose syntax such as MOVE x TO y, which was designed to be self-documenting and highly readable. However, it is verbose and uses over 300 reserved words compared to the succinct and mathematically inspired syntax of other languages. (Full article...)
is a
general-purpose programming languageemphasizing
performance,
type safety, and
concurrency. It enforces
memory safety, meaning that all
referencespoint to valid memory. It does so without a conventional
garbage collector; instead, memory safety errors and
data racesare prevented by the "borrow checker", which tracks the
object lifetimeof references
at compile time.
Rust supports multiple programming paradigms. It was influenced by ideas from functional programming, including immutability, higher-order functions, algebraic data types, and pattern matching. It also supports object-oriented programming via structs, enums, traits, and methods.
Software developer Graydon Hoare created Rust as a personal project while working at Mozilla Research in 2006. Mozilla officially sponsored the project in 2009. The first stable release of Rust, Rust 1.0, was published in May 2015. Following a large layoff of Mozilla employees in August 2020, multiple other companies joined Mozilla in sponsoring Rust through the creation of the Rust Foundation in February 2021. In December 2022, Rust became the first language other than C and assembly to be supported in the development of the Linux kernel. (Full article...)
deals with generating
imagesand art with the aid of
computers. Computer graphics is a core technology in digital photography, film, video games, digital art, cell phone and computer displays, and many specialized applications. A great deal of specialized hardware and software has been developed, with the displays of most devices being driven by
computer graphics hardware. It is a vast and recently developed area of computer science. The phrase was coined in 1960 by computer graphics researchers Verne Hudson and
William Fetterof Boeing. It is often abbreviated as CG, or typically in the context of film as
computer generated imagery(CGI). The non-artistic aspects of computer graphics are the subject of
computer scienceresearch.
Some topics in computer graphics include user interface design, sprite graphics, raster graphics, rendering, ray tracing, geometry processing, computer animation, vector graphics, 3D modeling, shaders, GPU design, implicit surfaces, visualization, scientific computing, image processing, computational photography, scientific visualization, computational geometry and computer vision, among others. The overall methodology depends heavily on the underlying sciences of geometry, optics, physics, and perception.
Computer graphics is responsible for displaying art and image data effectively and meaningfully to the consumer. It is also used for processing image data received from the physical world, such as photo and video content. Computer graphics development has had a significant impact on many types of media and has revolutionized animation, movies, advertising, and video games, in general. (Full article...)
The
history of artificial intelligence(
AI) began in
antiquity, with myths, stories, and rumors of artificial beings endowed with intelligence or consciousness by master craftsmen. The study of logic and formal reasoning from antiquity to the present led directly to the invention of the
programmable digital computerin the 1940s, a machine based on abstract mathematical reasoning. This device and the ideas behind it inspired scientists to begin discussing the possibility of building an
electronic brain.
The field of AI research was founded at a workshop held on the campus of Dartmouth College in 1956. Attendees of the workshop became the leaders of AI research for decades. Many of them predicted that machines as intelligent as humans would exist within a generation. The U.S. government provided millions of dollars with the hope of making this vision come true.
Eventually, it became obvious that researchers had grossly underestimated the difficulty of this feat. In 1974, criticism from James Lighthill and pressure from the U.S.A. Congress led the U.S. and British Governments to stop funding undirected research into artificial intelligence. Seven years later, a visionary initiative by the Japanese Government and the success of expert systems reinvigorated investment in AI, and by the late 1980s, the industry had grown into a billion-dollar enterprise. However, investors' enthusiasm waned in the 1990s, and the field was criticized in the press and avoided by industry (a period known as an "AI winter"). Nevertheless, research and funding continued to grow under other names. (Full article...)
The
analytical enginewas a proposed
digital mechanical general-purpose computerdesigned by English mathematician and computer pioneer
Charles Babbage. It was first described in 1837 as the successor to Babbage's
difference engine, which was a design for a simpler mechanical calculator.
The analytical engine incorporated an arithmetic logic unit, control flow in the form of conditional branching and loops, and integrated memory, making it the first design for a general-purpose computer that could be described in modern terms as Turing-complete. In other words, the structure of the analytical engine was essentially the same as that which has dominated computer design in the electronic era. The analytical engine is one of the most successful achievements of Charles Babbage.
Babbage was never able to complete construction of any of his machines due to conflicts with his chief engineer and inadequate funding. It was not until 1941 that Konrad Zuse built the first general-purpose computer, Z3, more than a century after Babbage had proposed the pioneering analytical engine in 1837. (Full article...)
Computer hardware includes the physical parts of a computer, such as the central processing unit (CPU), random-access memory (RAM), motherboard, computer data storage, graphics card, sound card, and computer case. It includes external devices such as a monitor, mouse, keyboard, and speakers.
By contrast, software is a set of written instructions that can be stored and run by hardware. Hardware derived its name from the fact it is hard or rigid with respect to changes, whereas software is soft because it is easy to change.
Hardware is typically directed by the software to execute any command or instruction. A combination of hardware and software forms a usable computing system, although other systems exist with only hardware. (Full article...)
A view of the
GNU nanoText editor version 6.0
standing next to the navigation software that she and her MIT team produced for the
Apollo Project.
at the UNIVAC keyboard, c. 1960. Grace Brewster Murray: American mathematician and rear admiral in the U.S. Navy who was a pioneer in developing computer technology, helping to devise UNIVAC I. the first commercial electronic computer, and naval applications for COBOL (common-business-oriented language).
This image (when viewed in full size, 1000 pixels wide) contains 1 million
pixels, each of a different color.
is a British-American computer scientist, physicist, and businessman. He is known for his work in computer science, mathematics, and in theoretical physics.
Animation of a
Non-uniform rational B-splinesurface. Modeled and rendered in
Cobalt.
Image 7Output from a (linearised) shallow water equation model of water in a bathtub. The water experiences 5 splashes which generate surface gravity waves that propagate away from the splash locations and reflect off of the bathtub walls.
's
Glider Gunin action
An IBM Port-A-Punch
punched cardShell, GNOME Clocks, Evince, gThumb and GNOME Files at version 3.30, in a dark theme
A screenshot of
GNU Emacs22.0.91.1, from
Ubuntu’s emacs-snapshot-gtk package.
A
head crashon a modern hard disk drive
An animation of the
quicksort algorithmsorting an array of randomized values
was an English mathematician and writer, chiefly known for her work on
Charles Babbage's proposed mechanical general-purpose
computer, the
Analytical Engine. She was the first to recognize that the machine had applications beyond pure calculation, and to have published the first
algorithmintended to be carried out by such a machine. As a result, she is often regarded as the first
computer programmer.
Partial map of the
Internetbased on the January 15, 2005 data found on opte.org. Each line is drawn between two nodes, representing two IP addresses. The length of the lines are indicative of the delay between those two nodes. This graph represents less than 30% of the Class C networks reachable by the data collection program in early 2005.
A lone house. An image made using
Blender 3D.
Partial view of the
Mandelbrot set. Step 1 of a zoom sequence: Gap between the "head" and the "body" also called the "seahorse valley".
was a
chess-playing expert systemrun on a unique purpose-built
IBM supercomputer. It was the first computer to win a
game, and the first to win a match, against a reigning world champion under regular time controls. Photo taken at the
Computer History Museum.
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