Topic 7

Selection and use of appropriate software

Applications Software

Applications software is software that’s created for a particular purpose or application. It’s not usually applied to the management of the resources of the computer such as memory, time spent processing jobs and dealing with input or output.


  • Databases
  • Browsers
  • Word-processors
  • Games

Systems Software

Systems software manages and controls the hardware which is necessary to allow the applications software to do a good job.


  • Operating system
  • GUI (Graphical User Interface)
  • File Management
  • Utilities

Operating System

The primary purpose of an operating system is to allow applications software to interact with the computer hardware. It allows the computer hardware to behave predictably so it can be used by applications software.

Tasks an operating system would perform

  • Diagnostic checks – performs some diagnostic checks when the computer is switched on
  • Controls the receipt of input from the input devices such as the keyboard and mouse
  • Controls output – sends information to the screen or other output devices
  • Memory management – controls the memory allocation needed by programs
  • Controls the flow of data to and from the main processor
  • Works out where to store the data on the hard disk drive
  • Deals with security issues such as usernames and passwords
  • Handles the interrupts which occur when applications software contains bugs or there is a hardware fault