Computing

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For the formal concept of computation, see computation. For the magazine, see Computing (magazine). For the scientific journal, see Computing (journal).

RAM (Random Access Memory)

Computing is usually defined as the activity of using and developing computer technology, computer hardware and software. It is the computer-specific part of information technology. Computer science (or computing science) is the study and the science of the theoretical foundations of information and computation and their implementation and application in computer systems.

Computing Curricula 2005^[1] defined computing:

In a general way, we can define computing to mean any goal-oriented activity requiring, benefiting from, or creating computers. Thus, computing includes designing and building hardware and software systems for a wide range of purposes; processing, structuring, and managing various kinds of information; doing scientific studies using computers; making computer systems behave intelligently; creating and using communications and entertainment media; finding and gathering information relevant to any particular purpose, and so on. The list is virtually endless, and the possibilities are vast.

A computer is a machine that manipulates data according to a set of instructions called computer programs. A computer requires programs to function, typically executing the program's instructions in a central processor. Computer programs are found either in executable form or as the source code from which executable programs are derived (e.g., compiled). In addition to running in a computer, the source of a program may be used to describe an algorithm to a human reader.

The execution process carries out the instructions of a computer program. The instructions in the program trigger sequences of simple actions on the executing machine. Those actions produce effects according to the semantics of the instructions in the program.

Computer programming is the process of writing, testing, debugging/troubleshooting, and maintaining the source code of computer programs. This source code is written in a programming language, which is a machine-readable artificial language designed to express the computations performed by the computer. The purpose of programming is to create a program that exhibits a certain desired behaviour (customization). The process of writing source code often requires expertise in many different subjects, including knowledge of the application domain, specialized algorithms and formal logic.

[edit] Definitions

The term computing has sometimes been narrowly defined, as in a 1989 ACM report on Computing as a Discipline^[2]:

The discipline of computing is the systematic study of algorithmic processes that describe and transform information: their theory, analysis, design, efficiency, implementation, and application. The fundamental question underlying all computing is 'What can be (efficiently) automated?'

Computing Curricula 2005^[1] also recognizes that the meaning of computing depends on the context:

Computing also has other meanings that are more specific, based on the context in which the term is used. For example, an information systems specialist will view computing somewhat differently from a software engineer. Regardless of the context, doing computing well can be complicated and difficult. Because society needs people to do computing well, we must think of computing not only as a profession but also as a discipline.

The term computing is also synonymous with counting and calculating. In earlier times it was used in reference to mechanical computing machines.

A computer is an electronic device that performs certain arithmetic and logical operations without any errors.

[edit] Science and theory

Computer science
Theory of computation
Computational models
Digital Bibliography & Library Project, as of July 2007, lists over 910 000 bibliographic entries on computer science and several thousand links to the home pages of computer scientists
Scientific computing
Metacomputing
Topological computing

[edit] Hardware

See information processor for a high-level block diagram.

[edit] Instruction-level taxonomies

After the commoditization of memory, attention turned to optimizing CPU performance at the instruction level. Various methods of speeding up the fetch-execute cycle include:

designing instruction set architectures with simpler, faster instructions: RISC as opposed to CISC
Superscalar instruction execution
VLIW architectures, which make parallelism explicit