Computer software or simply software is any set of instructions that directs a computer to perform specific operations. Computer software consists of computer programs, libraries and related non-executable data (such as online documentation or digital media). Computer software is non-tangible, contrasted with computer hardware, which is the physical component of computers. Computer hardware and software require each other and neither can be realistically used without the other.
Based on the goal, computer software can be divided into:
Application software, which is software that uses the computer system to perform special functions or provide entertainment functions beyond the basic operation of the computer itself. There are many different types of application software, because the range of tasks that can be performed with a modern computer is so large—see list of software.
System software, which is software that directly operates the computer hardware, to provide basic functionality needed by users and other software, and to provide a platform for running application software. System software includes:
Operating systems, which are essential collections of software that manage resources and provides common services for other software that runs “on top” of them. Supervisory programs, boot loaders, shells and window systems are core parts of operating systems. In practice, an operating system comes bundled with additional software (including application software) so that a user can potentially do some work with a computer that only has an operating system.
Device drivers, which operate or control a particular type of device that is attached to a computer. Each device needs at least one corresponding device driver; because a computer typically has at minimum at least one input device and at least one output device, a computer typically needs more than one device driver.
Utilities, which are computer programs designed to assist users in maintenance and care of their computers.
Malicious software or malware, which is software that is developed to harm and disrupt computers. As such, malware is undesirable. Malware is closely associated with computer-related crimes, though some malicious programs may have been designed as practical jokes.