Operating Systems
Computer Science: OCR A Level, topic 2.1.1
Operating Systems
An operating system is an essential piece of software that is loaded when a computer boots up.
Purpose of the OS
- An operating system (OS) is a piece of system software which controls the hardware within a computer.
API
- Operating systems provide an application programming interface (API).
- This is a set of code libraries that software developers can use to write applications for that operating system.
Managers
- The operating system is responsible for many pieces of hardware, each of which is controlled by a dedicated 'manager':
- The user interface (UI) manager provides the user interface which allows users to control the computer.
- The device manager allocates resources to external hardware devices and allows them to be used by applications.
- The memory manager controls the allocation of memory between applications.
More managers
- The user manager authenticates and separates users of the computer.
- The process manager controls the allocation of central processing unit (CPU) cycles to multiple running applications.
- The file manager controls the opening, reading and writing of files in secondary storage.
Test yourself on Operating Systems
What is an application programming interface (API)?