Portal:Computer programming

In computer programming, assembly language (alternatively assembler language or symbolic machine code), often referred to simply as assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence between the instructions in the language and the architecture's machine code instructions. Assembly language usually has one statement per machine instruction (1:1), but constants, comments, assembler directives, symbolic labels of, e.g., memory locations, registers, and macros are 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...)

JavaScript (/ˈdʒɑːvəskrɪpt/), often abbreviated as JS, is a programming language and core technology of the Web, alongside HTML and CSS. 99% of websites use JavaScript on the client side for webpage behavior.

Web browsers have a dedicated JavaScript engine that executes the client code. These engines are also utilized in some servers and a variety of apps. The most popular runtime system for non-browser usage is Node.js.

JavaScript is a high-level, often just-in-time compiled language that conforms to the ECMAScript standard. It has dynamic typing, prototype-based object-orientation, and first-class functions. It is multi-paradigm, supporting event-driven, functional, and imperative programming styles. It has application programming interfaces (APIs) for working with text, dates, regular expressions, standard data structures, and the Document Object Model (DOM). (Full article...)

In the C++ programming language, decltype is a keyword used to query the type of an expression. Introduced in C++11, its primary intended use is in generic programming, where it is often difficult, or even impossible, to express types that depend on template parameters.

As generic programming techniques became increasingly popular throughout the 1990s, the need for a type-deduction mechanism was recognized. Many compiler vendors implemented their own versions of the operator, typically called typeof, and some portable implementations with limited functionality, based on existing language features were developed. In 2002, Bjarne Stroustrup proposed that a standardized version of the operator be added to the C++ language, and suggested the name "decltype", to reflect that the operator would yield the "declared type" of an expression.

decltype's semantics were designed to cater to both generic library writers and novice programmers. In general, the deduced type matches the type of the object or function exactly as declared in the source code. Like the sizeof operator, decltype's operand is not evaluated. (Full article...)

Python is a high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation.

Python is dynamically typed and garbage-collected. It supports multiple programming paradigms, including structured (particularly procedural), object-oriented and functional programming. It is often described as a "batteries included" language due to its comprehensive standard library.

Guido van Rossum began working on Python in the late 1980s as a successor to the ABC programming language and first released it in 1991 as Python 0.9.0. Python 2.0 was released in 2000. Python 3.0, released in 2008, was a major revision not completely backward-compatible with earlier versions. Python 2.7.18, released in 2020, was the last release of Python 2. (Full article...)

Rust is a general-purpose programming language emphasizing performance, type safety, and concurrency. It enforces memory safety, meaning that all references point to valid memory, without a garbage collector. To simultaneously enforce memory safety and prevent data races, its "borrow checker" tracks the object lifetime of all references in a program during compiling.

Rust was influenced by ideas from functional programming, including immutability, higher-order functions, and algebraic data types. It is popular for systems programming. Rust does not enforce a programming paradigm, but supports object-oriented programming via structs, enums, traits, and methods, and supports functional programming via immutability, pure functions, higher order functions, and pattern matching.

Software developer Graydon Hoare created Rust as a personal project while working at Mozilla Research in 2006. Mozilla officially sponsored the project in 2009. In the years following the first stable release in May 2015, Rust was adopted by companies including Amazon, Discord, Dropbox, Google (Alphabet), Meta, and Microsoft. In December 2022, it became the first language other than C and assembly to be supported in the development of the Linux kernel. (Full article...)

R is a programming language for statistical computing and data visualization. It has been adopted in the fields of data mining, bioinformatics, and data analysis.

The core R language is augmented by a large number of extension packages, containing reusable code, documentation, and sample data.

R software is open-source and free software. It is licensed by the GNU Project and available under the GNU General Public License. It is written primarily in C, Fortran, and R itself. Precompiled executables are provided for various operating systems. (Full article...)

Eiffel is an object-oriented programming language designed 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 becoming available in 1986. In 2005, Eiffel became an ISO-standardized language.

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 later found their way 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...)

Linus Benedict Torvalds (/ˈliːnəs ˈtɔːrvɔːldz/ LEE-nəs TOR-vawldz, Finland Swedish: [ˈliːnʉs ˈtuːrvɑlds] ^ⓘ; born 28 December 1969) is a Finnish-American software engineer who is the creator and lead developer of the Linux kernel. He also created the distributed version control system Git.

He was honored, along with Shinya Yamanaka, with the 2012 Millennium Technology Prize by the Technology Academy Finland "in recognition of his creation of a new open source operating system for computers leading to the widely used Linux kernel." He is also the recipient of the 2014 IEEE Computer Society Computer Pioneer Award and the 2018 IEEE Masaru Ibuka Consumer Electronics Award. (Full article...)

Lisp (historically LISP, an abbreviation of "list processing") is a family of programming languages with a long history and a distinctive, fully parenthesized prefix notation.
Originally specified in the late 1950s, it is the second-oldest high-level programming language still in common use, after Fortran. Lisp has changed since its early days, and many dialects have existed over its history. Today, the best-known general-purpose Lisp dialects are Common Lisp, Scheme, Racket, and Clojure.

Lisp was originally created as a practical mathematical notation for computer programs, influenced by (though not originally derived from) the notation of Alonzo Church's lambda calculus. It quickly became a favored programming language for artificial intelligence (AI) research. As one of the earliest programming languages, Lisp pioneered many ideas in computer science, including tree data structures, automatic storage management, dynamic typing, conditionals, higher-order functions, recursion, the self-hosting compiler, and the read–eval–print loop.

The name LISP derives from "LISt Processor". Linked lists are one of Lisp's major data structures, and Lisp source code is made of lists. Thus, Lisp programs can manipulate source code as a data structure, giving rise to the macro systems that allow programmers to create new syntax or new domain-specific languages embedded in Lisp. (Full article...)

In computer science and computer engineering, computer architecture is a description of the structure of a computer system made from component parts. It can sometimes be a high-level description that ignores details of the implementation. At a more detailed level, the description may include the instruction set architecture design, microarchitecture design, logic design, and implementation. (Full article...)

Go is a statically typed, compiled high-level programming language designed at Google by Robert Griesemer, Rob Pike, and Ken Thompson. It is syntactically similar to C, but also has memory safety, garbage collection, structural typing, and CSP-style concurrency. It is often referred to as Golang because of its former domain name, golang.org, but its proper name is Go.

There are two major implementations:

• Google's self-hosting "gc" compiler toolchain, targeting multiple operating systems and WebAssembly.
• gofrontend, a frontend to other compilers, with the libgo library. With GCC the combination is gccgo; with LLVM the combination is gollvm.

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In computing, a linker or link editor is a computer system program that takes one or more object files (generated by a compiler or an assembler) and combines them into a single executable file, library file, or another "object" file.

A simpler version that writes its output directly to memory is called the loader, though loading is typically considered a separate process. (Full article...)

In mathematics and computer science, an algorithm (/ˈælɡərɪðəm/ ^ⓘ) is a finite sequence of mathematically rigorous instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing calculations and data processing. More advanced algorithms can use conditionals to divert the code execution through various routes (referred to as automated decision-making) and deduce valid inferences (referred to as automated reasoning), achieving automation eventually. Using human characteristics as descriptors of machines in metaphorical ways was already practiced by Alan Turing with terms such as "memory", "search" and "stimulus".

In contrast, a heuristic is an approach to problem-solving that may not be fully specified or may not guarantee correct or optimal results, especially in problem domains where there is no well-defined correct or optimal result. For example, social media recommender systems rely on heuristics in such a way that, although widely characterized as "algorithms" in 21st-century popular media, cannot deliver correct results due to the nature of the problem.

As an effective method, an algorithm can be expressed within a finite amount of space and time and in a well-defined formal language for calculating a function. Starting from an initial state and initial input (perhaps empty), the instructions describe a computation that, when executed, proceeds through a finite number of well-defined successive states, eventually producing "output" and terminating at a final ending state. The transition from one state to the next is not necessarily deterministic; some algorithms, known as randomized algorithms, incorporate random input. (Full article...)

Paul Gardner Allen (January 21, 1953 – October 15, 2018) was an American businessman, computer programmer, researcher, film producer, explorer, sports executive, investor and philanthropist. He co-founded Microsoft Corporation with his childhood friend Bill Gates in 1975, which helped spark the microcomputer revolution of the 1970s and 1980s. Allen was ranked as the 44th-wealthiest person in the world by Forbes with 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. 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...)

In computer systems a loader is the part of an operating system that is responsible for loading programs and libraries. It is one of the essential stages in the process of starting a program, as it places programs into memory and prepares them for execution. Loading a program involves either memory-mapping or copying the contents of the executable file containing the program instructions into memory, and then carrying out other required preparatory tasks to prepare the executable for running. Once loading is complete, the operating system starts the program by passing control to the loaded program code.

All operating systems that support program loading have loaders, apart from highly specialized computer systems that only have a fixed set of specialized programs. Embedded systems typically do not have loaders, and instead, the code executes directly from ROM or similar. In order to load the operating system itself, as part of booting, a specialized boot loader is used. In many operating systems, the loader resides permanently in memory, though some operating systems that support virtual memory may allow the loader to be located in a region of memory that is pageable.

In the case of operating systems that support virtual memory, the loader may not actually copy the contents of executable files into memory, but rather may simply declare to the virtual memory subsystem that there is a mapping between a region of memory allocated to contain the running program's code and the contents of the associated executable file. (See memory-mapped file.) The virtual memory subsystem is then made aware that pages with that region of memory need to be filled on demand if and when program execution actually hits those areas of unfilled memory. This may mean parts of a program's code are not actually copied into memory until they are actually used, and unused code may never be loaded into memory at all. (Full article...)