Operating systems

An operating system (or 'OS') controls the general operation of a computer, and provides an easy way for us to interact with computers and run applications.

Graphic illustrating different software interfaces

On some computers it is possible to run a choice of operating systems. Games consoles have their own unique operating systems.

There are a few common operating systems available:

  • Mac OS X
  • Linux
  • Windows
  • Android (based on Linux)
  • iOS

Functions of the operating system

The operating system performs several key functions:

  • interface - provides a user interface so it is easy to interact with the computer
  • manages the CPU - runs applications and executes and cancels processes
  • multi-tasks - allows multiple applications to run at the same time
  • manages memory - transfers programs into and out of memory, allocates free space between programs, and keeps track of memory usage
  • manages peripherals - opens, closes and writes to peripheral devices such as storage attached to the computer
  • organises - creates a file system to organise files and directories
  • security - provides security through user accounts and passwords
  • utilities - provides tools for managing and organising hardware
Glossary
  1. application A software program that allows a user to perform a specific task.
  2. buffer A temporary area of computer memory used to store data for running processes.
  3. command line A method of running programs and working on a computer using only text. This contrasts with a graphical interface which uses clickable icons and menus.
  4. corrupt A computer file that is damaged, possibly unusable.
  5. CPU Central processing unit - the brain of the computer that processes program instructions. Also called a microprocessor.
  6. encryption Files that are encrypted have been altered using a secret code and are unreadable to unauthorised parties.
  7. hardware The physical parts of a computer system, eg a graphics card, hard disk drive, CD drive etc.
  8. machine code Also called object-code, this is low-level code that represents how computer hardware and CPUs understand instructions. It is represented by binary numbers.
  9. memory The part of a computer that stores data.
  10. operating system The software that runs a computer.
  11. OSX A version of Apple's Mac OS operating system for Apple computers.
  12. peripheral A piece of hardware that connects to a computer, eg a mouse, keyboard, printer or scanner.
  13. port A physical interface on a computer to connect externals such as mice and keyboards. Over a network a port is a point where information is sent through, eg the http port.
  14. protocol A set of rules for how messages are turned into data packets and sent across networks.
  15. RAM Random Access Memory (RAM): Memory that is constantly being written to and read from. It does not retain its contents without a constant supply of power, eg when a computer is turned off, everything stored in its RAM is lost.
  16. smartphone A mobile phone with a powerful processor that is capable of running applications and accessing the internet.
  17. storage The hardware of a computer that stores data long term, such as a memory card or hard drive.
  18. stream A method of downloading digital media such as audio and video as a temporary file.
  19. virus Computer code designed to damage a computer system.
  20. Windows Microsoft's brand of operating systems, eg Windows 98, Windows XP, Windows Vista, etc.