1. Nat 4/5 Computing Science Operating Systems
Computer Systems
Nat 4/5 Computing Science
Operating Systems

2. Lesson Aims By the end of this lesson: All pupils will be able to:
Describe what an operating system is
Describe what an application program is
Describe the functions of an operating system

3. Types of software There are two main types of software: Applications
Nat 4/5
Types of software
There are two main types of software:
Applications
These are pieces of software that perform a particular task such as word processing or desktop publishing
Systems Software (Operating Systems)
These types of software control the running of hardware and the running of other software

4. Applications Software
Nat 4/5
Applications Software
Application software are programs that are designed to do a particular task.
For example the Word Processor your revision notes were written in is an application program.
Even games are application programs.

5. Nat 4/5
Operating Systems
An operating system is a piece of software that controls the operation of the systems hardware and the running of other software.
Two of the more popular operating systems used at present are
Microsoft® Windows
Apple® OSX.

6. Why is it important? You are writing an app for a smartphone
Nat 4/5
Why is it important?
You are writing an app for a smartphone
Which operating system do you write it for?
IOS® Android ® Windows ® ?
Why do you need to bear this in mind?
If I buy Office 2010 for windows – can I install it on a Mac?

7. Operating Systems: Functions
Nat 4/5
Operating Systems: Functions
All operating systems have certain common functions:
Provision of an Interface
This is the means of interacting with the user. Most modern operating systems provide a GUI (Graphical User Interface)
Input Output
Controls the sending and receiving of data to and from peripherals
Memory Management
Controls the systems RAM, controlling which locations in RAM programs are loaded into
File Management
Controls where and how files are saved onto backing storage.
Error Reporting
Providing useful feedback to users when errors do occur.

8. Nat 4/5
Summary
The Operating System (OS) of a computer is a program which manages the hardware and the running of other software on a computer system.
The standard functions of an OS are:
Provision of an interface
Input/Output
File Management
Memory management
Error Reporting
An application program is a piece of software that performs a particular task such as games, word processers.