The need for, function and purpose of operating systems

1.2.1 Systems Software

Systems Software — Note 1 of 8

Candidates need to have an understanding of why an operating system is required, along with the different tasks it performs within a computer system e.g. resource management, file management, interrupt handling, security, providing a platform for software to run, providing a user interface and providing utilities

What you need to know

An operating system (OS) manages the computer's hardware and software resources and provides a platform on which applications run. Without an OS, every program would have to control the hardware directly and the computer would be very difficult to use.

What to know

Resource management: allocating processor time, memory and I/O devices between programs.
Memory management: allocating and freeing RAM, using paging, segmentation and virtual memory.
Processor scheduling: deciding which process runs next and for how long.
Interrupt handling: responding to signals from hardware and software.
File management: organising files into directories, controlling access and tracking where files are stored.
Security: user accounts, passwords, access rights and permissions.
Providing a user interface (GUI or command line) and utilities, and communicating with peripherals through device drivers.
The OS hides the complexity of the hardware from applications and users (an example of abstraction).

Key terms

Operating system: System software that manages hardware and software resources, provides a user interface and provides a platform for applications to run.

Exam technique

Tip:When explaining why an OS is needed, give specific functions and explain each one, rather than simply listing them.

Ready to test yourself?

Practise 1.2.1 questions

← Previous topicVirtual storage1.1.3 Input, output and storage Next note →Memory management: paging, segmentation and virtual memory1.2.1 Systems Software

Back to Systems Software