Operating System

• Systems software is the connection between the computer system hardware and the applications that run on the system
• System software is comprised of:
• System software is comprised of:

  • The operating system
  • Utility applications which perform a specific function e.g., backing up data
• The operating system is a collection of programs that work together to tell the hardware what to do
• The Operating system:

  • Allows the user to use the hardware
  • Provides a user interface
  • Manages the computer hardware and peripherals
  • Provides management of memory and files by allocating, extending and restoring files and storage as and when required
  • Manages security and organising data so it is not overwritten
• Graphical User Interface


  • Most common form of user interface
  • Windows, Linux, iOS, Android are examples of operating systems which use GUIs
  • WIMP (Windows, Icons, Menus and Pointers)
• Command Line Interface


  • Allows users to type commands directly into the system
• Voice Control and Gesture Control


  • Use artificial intelligence
• Computer systems load applications from secondary storage such as hard disc drives into their primary storage which is usually the computer RAM
• Operating System allocates memory to each application as it needs it
• When a program is closed, the operating system will try to reclaim all the allocated memory so other programs can use it
• Memory leaks are where poorly written software may not hand back all the memory it has been allocated. These cause computer RAM to lock up.
• Whenever the computer is re-booted, the RAM is completely cleared
• Multi-tasking is dividing the amount of processing power that is available between all the programs the require it
• Multi-tasking is done by the operating system allocating small "slices" of time, which may leach last for hundredths of a second
• Peripheral Management is connected to a modern computer using a driver.
• Driver software may need to be updated to fix bugs or introduce new features
• Allocation of an account is where operating systems allow user accounts to be created. Each have their own personalised desktop background, default colours and fonts, and have their own user area
• Access Rights are responsible by the operating system. This is where users may not have access to specific documents unless given permission
• Security ensures that there are passwords or PINs to avoid unauthorised access
• User management:


  • Allocation of an account
  • Access rights
  • Security
• Every computer system needs to be able to manage files
• When you save a large number of files, it is very easy to lose them
• Operating systems can organise the files by using folders or labels adding contextual description to them
• Files can also have a file type associated with them
• The operating system may also encrypt the files to keep them more secure