Operating systems
An operating system is a multilayer suite of software that provides an environment in which applications perform useful functions such as word processing, placing telephone calls, or managing the operation of a car engine. Applications running under control of the operating system execute algorithms implemented as processor instruction sequences and perform I/O interactions with peripheral devices as required to complete their tasks.
The operating system provides standardized programming interfaces that application developers use to access system resources such as processor execution threads, disk files, input from a keyboard or other peripherals, and output to devices such as a computer screen or instruments on an automotive dashboard.
Operating systems can be broadly categorized as real-time or non-real-time:
