System software

• Operating systems manage hardware and run software
• Give some functions of the OS


  Communicate with internal and external hardware

  Provide user interface

  Provide a platform for running applications

  Allow multi-tasking

  Deal with file management and disk management

  Manage system security (user accounts and access levels)
• What do device drivers do?


  Allow the OS and hardware to talk to each other
• Device drivers act as translators for the signals between OS and hardware
• When a new hardware is connected, the matching device drivers will be installed
• Updates to device drivers happen automatically
• What does a user interface do?

  Allows the user to interact with a computer system
• Give an example of a user interface

  GUI - graphical user interface (for everyday use)
• What is a command line interfaced based as?

  text-based
• How does the OS allow multitasking?


  By managing resources and running multiple applications at the same time
• What does a memory manager do to assist multitasking?

  allocates certain applications certain memory locations, so they are stored separately and don't overwrite each other.
• The OS helps to manage the flow of data by using what?

  memory buffers
• The OS handles file and disk management
• The OS may include utility software. Give some examples.

  File compression software

  Encryption software

  Defragmentation software
• The OS can be single-user or multi-user.
• What do defragmentation utilities do?

  Put broken up files back together
• When does fragmentation occur?

  When files are moved, deleted and change size.
• What does fragmentation cause?

  small gaps appear on the disk
• How does a fragmented disk affect speed?

  Makes reading and writing files slower
• Defragmentation software does what to data?

  reorganises it
• What type of storage isn't affected by fragmentation?

  SSDs
• Why does fragmentation affect hard disks but not SSDs?

  SSDs don't have moving parts but hard disk have a head that moves back and forth
• Compression software does what?

  reduces file size by permanently or temporarily removing data from them
• Encryption software can help protect what?

  files and data
• What does encryption software do?

  scrambles data to stop third parties from accessing it
• What is needed to decrypt data?

  a key