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In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity. Depending on the operating system (OS), a process may be made up of multiple threads of execution that execute instructions concurrently.[1][2]

A computer program is a passive collection of instructions, while a process is the actual execution of those instructions. Several processes may be associated with the same program; for example, opening up several instances of the same program often means more than one process is being executed.

Multitasking is a method to allow multiple processes to share processors (CPUs) and other system resources. Each CPU executes a single task at a time. However, multitasking allows each processor to switch between tasks that are being executed without having to wait for each task to finish. Depending on the operating system implementation, switches could be performed when tasks perform input/output operations, when a task indicates that it can be switched, or on hardware interrupts.

A common form of multitasking is time-sharing. Time-sharing is a method to allow fast response for interactive user applications. In time-sharing systems, context switches are performed rapidly, which makes it seem like multiple processes are being executed simultaneously on the same processor. This seeming execution of multiple processes simultaneously is called concurrency.

For security and reliability, most modern operating systems prevent direct communication between independent processes, providing strictly mediated and controlled inter-process communication functionality.


A collection of instructions that performs a specific task when executed by a computer.

An organized list of instructions that, when executed, causes the computer to behave in a predetermined manner. Without programs, computers are useless.


A programmer, computer programmer, developer, dev, coder, or software engineer a person who writes computer software. The term computer programmer can refer to a specialist in one area of computer programming or to a generalist who writes code for many kinds of software. One who practices or professes a formal approach to programming may also be known as a programmer analyst. A programmer’s primary computer language (Assembly, COBOL, C, C++, C#, Java, Lisp, Python, etc.) is often prefixed to these titles, and those who work in a Web environment often prefix their titles with Web. The term programmer can be used to refer to a software developer, Web developer, mobile applications developer, embedded firmware developer, software engineer, computer scientist, or software analyst. However, members of these professions possess other software engineering skills, beyond programming; for this reason, the term programmer, or code monkey, is sometimes considered an insulting or derogatory oversimplification of these other professions. This has sparked much debate amongst developers, analysts, computer scientists, programmers, and outsiders who continue to be puzzled at the subtle differences in the definitions of these occupations.


An outline of a program, written in a form that can easily be converted into real programming statements.



An interpreted, object-oriented programming language developed by Guido van Rossum. The name comes from one of van Rossum’s favorite television shows, Monty Python’s Flying Circus. Python is very portable since Python interpreters are available for most operating system platforms.