1 (Topics 5-6)
1.5 Systems software
Types of System Software
System software controls the hardware of the computer and provides an
environment for applications to run.
Utility software
performs maintenance tasks to make sure the operation of the system
continues
OS systems manage access to hardware in the computer
Device drivers are small programs which tell the operating system how to
use a piece of hardware
Utility software helps maintain the system
there are four main types of utility software
Defragmentation
improves the hard disk performance by reorganising data
Backup
makes copies of data that can be restored in the event of a data
loss
Encryption
prevents unauthorised access to files by scrambling the data
Compression
reducing the space needed to represent a file
GCSE Computer Science Paper 1 (Topics 5-6) 1
, Operating Systems
An operating system is an essential piece of software that is loaded when a
computer boots up and controls the hardware within a computer
It provides an application programming interface (API)
An API is a set of code libraries that software developers can use to write
apps for that OS
The hardware the OS is responsible for is controlled by a manager
The six managers are:
User interface (UI) manager
provides the user interface so users can control the computer
Device manager
allocates resources to external hardware so they can be used by
apps
Memory manager
controls the allocations of memory between apps
User manager
authenticates and separates users of the computer
Process manager
controls the allocations of the CPU cycles to multiple running apps
File manager
controls the opening, reading and writing of files in secondary
storage
Operating System Managers
Graphical user interfaces
GUIs are more modern environments to work in that are based on the
window-icon-menu-pointer paradigm or a multi-touch interface
GCSE Computer Science Paper 1 (Topics 5-6) 2