Computing

Computing refers to any purposeful activity that involves, is aided by, or results in computing machinery. This field covers the investigation and testing of algorithmic processes, along with the creation of hardware and software. It draws from scientific, engineering, mathematical, technological, and social domains. Key areas within computing include computer engineering, computer science, cybersecurity, data science, information systems, information technology, and software engineering. The word computing has also been used to mean counting and calculating. Historically, it described the work done by mechanical calculating machines, and even earlier, by people who performed calculations manually.

The history of computing goes back further than the history of computing hardware. It includes methods designed for pen and paper (or chalk and slate), sometimes aided by tables. Computing is closely linked to how numbers are represented, though mathematical ideas needed for computing existed before number systems. The oldest known tool for computation is the abacus, believed to have been invented in Babylon between 2700 and 2300 BC. More modern versions of the abacus are still used for calculations today. The first recorded suggestion to use digital electronics for computing appeared in a 1931 paper by C. E. Wynn-Williams. Claude Shannon's 1938 paper then introduced the concept of using electronics for Boolean algebra operations. The idea of a field-effect transistor was proposed by Julius Edgar Lilienfeld in 1925. In 1947, John Bardeen and Walter Brattain, working under William Shockley at Bell Labs, built the first working transistor, a point-contact type. The University of Manchester built the first transistorized computer, the Manchester Baby, in 1953. Early junction transistors were large and hard to mass-produce, so they were only used in specialized applications. In 1957, Frosch and Derick at Bell Labs manufactured the first silicon dioxide field effect transistors, where the drain and source were adjacent on the surface. A working MOSFET was demonstrated at Bell Labs in 1960. This device enabled high-density integrated circuits, leading to what is called the computer revolution or microcomputer revolution.

A computer is a machine that processes data based on a set of instructions known as a computer program. The program has an executable form that the computer can run directly. The same program, in its human-readable source code, allows a programmer to study and develop a sequence of steps called an algorithm. Since instructions can be executed on different types of computers, a single set of source instructions is converted into machine instructions depending on the CPU type. The execution process carries out the instructions in a program. These instructions express the computations the computer performs and trigger simple actions on the machine, producing effects according to the instructions' semantics.

Computer hardware consists of the physical parts of a computer, such as the central processing unit, memory, and input/output devices. Computational logic and computer architecture are important topics in hardware.

Computer software, often just called software, is a collection of computer programs and related data that gives instructions to a computer. It refers to one or more programs and data stored in the computer's memory. Software includes programs, procedures, algorithms, and documentation related to operating a data processing system. Program software performs the function of the program it implements, either by directly instructing the hardware or by serving as input to another piece of software. The term was created to contrast with hardware, which refers to physical devices. Unlike hardware, software is intangible. Sometimes software is used in a narrower sense to mean only application software.

System software is designed to operate and control computer hardware and provide a platform for running application software. It includes operating systems, utility software, device drivers, window systems, and firmware. Commonly used development tools like compilers, linkers, and debuggers are also classified as system software. System software and middleware manage and integrate a computer's capabilities but typically do not directly perform tasks that benefit the user, unlike application software.

Application software, also called an application or app, is designed to help the user perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software, and media players. Many application programs mainly work with documents. Apps may come bundled with the computer and its system software, or they may be published separately. Some users are satisfied with bundled apps and never need to install additional ones. The system software manages the hardware and serves the application, which in turn serves the user. Application software uses the power of a particular computing platform or system software for a specific purpose. Some apps, like Microsoft Office, are developed in multiple versions for different platforms; others have narrower requirements and are referred to by the platform they run on. For example, a geography application for a specific platform.