1.5 system software

• Operating System (OS)


  Manages the hardware in a computer and provides an environment for applications to run
• Systems software


  Controls the hardware inside the computer and provides an interface for users to interact with it, comprised of the operating system and utility software
• Application software


  The end-user programs that are designed to perform specific tasks, such as word processing, photo editing
• Functions controlled by the OS

  • User interface to allow the user to interact with the system
  • Memory management to control the use of the RAM and to share processor time between different programs and processes
  • Peripheral management to control peripheral devices using drivers
  • User management to control who can access the computer and what resources they can use
  • File management to allow users to organise their work into folders and subfolders
• Utility software


  A collection of programs each of which does a specific housekeeping task to help maintain a computer system
• Encryption software


  Used to encode data so that it cannot be understood if it is intercepted by unauthorised users, uses an algorithm and key to transform plaintext into ciphertext
• Defragmentation


  Reorganises files on a hard drive, putting all of the free space together and all of the parts of the same file together, to improve performance
• Data compression software


  Uses algorithms to reduce the size of files so that they take up less storage space, can be lossy or lossless