1. Lesson Objectives By the end of this lesson you will be able to:
(a) Define hardware, giving examples
(b) Define software, giving examples
(c) Describe the difference between hardware and software
(d) Identify the main components of a general-purpose computer: central processing unit, main/internal memory (including ROM and RAM)

2. Hardware or Software? 1. Printer - 2. Adobe Acrobat - 3. Windows 7 -
You have 2 minutes to discuss with the person sitting next to you, which is hardware and which is software…
1. Printer -
2. Adobe Acrobat -
3. Windows 7 -
4. Motherboard -
5. Scanner -
6. Graphics Driver -
Hardware
Software
Software
Hardware
Hardware
Software

3. Definitions…
Hardware is a general term for the physical components that make up a computer system.
Write down 3 examples of hardware.
Software is a general term for the programs that control the computer system.
Write down 3 examples of software.
For a computer system to be useful it has to consist of both hardware and software.

4. With the person sitting next to you...
You have 2 minutes to discuss and label the diagram below:
Backing Storage Input Main Memory
Process Output

5. Title: Components of a Computer System
Draw the following diagram in your book:
INPUT
PROCESS
OUTPUT
MAIN
MEMORY
BACKING
STORAGE

6. Used to convert images on paper into digital format
Matching Up…
In pairs match each device to it’s type and description
For example:
Scanner
Input
Used to convert images on paper into digital format

7. Answers… Keyboard Input
It is made up of buttons called keys. The keys are arranged into different sections. The most common type is known as a QWERTY.
Mouse
A pointing device which controls what happens on the screen. The left button is usually used for selecting and the right button brings up menus.
Monitor
Output
The pictures displayed on it are made up of pixels. The two most commonly used ones are known as CRT’s and TFT’s.
Printer
These are used to create a hard copy of your work. Most produce their output on paper. They come in colour and black and white.
Central Processing
Unit
Process
The brain of the computer where all the searching, sorting, calculating and decision making takes place.
RAM
Main
Memory
This is volatile memory. The data is held on a chip, but only temporarily. The data disappears if the power is switched off.
ROM
The data stored is not erased when the power is switched off - it is permanent. This is called non volatile memory.
Stick
Backing
Storage
They are small, lightweight and rewritable. They consist of a small printed circuit board which is encased in plastic or metal casing.
DVD
They can be written to once and are used in all modern computers. They have a large storage capacity.

8. Components of a Computer System
You will be looking at input, output and storage devices later in the course.
For the rest of this lesson we will look at the Central Processing Unit (CPU) and Main Memory.
What do you think the CPU does?

9. Central Processing Unit
The CPU is the brain of the computer.
It is the device that carries out software instructions.
The Pentium processor made by Intel is an example of a CPU.
CPUs usually plug into a large socket on the main circuit board (the motherboard) of a computer.
They get very hot when they are operating so usually have a large fan attached to their top
to keep them cool.
No Past exam Questions

10. Main Memory
The CPU needs to store data whilst its carrying out the processing required.
The data or instructions that are to be processed by the CPU must be placed into main memory.
Memory can be classed into two types:
RAM and ROM

11. Random Access Memory (RAM)
Random Access Memory (RAM) is the part of the computer that temporarily stores the instructions that the computer is running, and the data it is processing.
RAM is a volatile storage device. This means that if the computer’s power is turned off the contents of RAM disappear and are lost.
When a computer is in use, its RAM will contain:
The operating system software
The application software currently being used
Any data that is being processed

12. RAM – Notes from Mark Schemes
Random Access Memory
A temporary store of data
Holds the date that is currently being used by the user
It is volatile so data is lost when the computer is turned off
It can be read from or written to
The data in RAM can be changed
It is needed so that users are able to make changes to the data they are working on/to store the program or data they are currently using

13. Read-Only Memory (ROM)
Read-Only Memory (ROM) is used in most computers to hold a small piece of software: the 'boot up' program.
This 'boot up' software is known as the BIOS (Basic Input Output System), it checks the computer’s hardware and then loads the operating system.
ROM is non-volatile storage. This means that the data it contains is never lost, even if the power is switched off.

14. ROM Notes from Mark Schemes
Read Only Memory
It is non-volitile so not lost when the computer is turned off
Stores things such as: BIOS, Programs in washing machine, program instructions for games
The data cannot be changed
It is used so that programs/coding/software can be stored permanently/cannot be changed

15. Lesson Summary This lesson we looked at:
What hardware and software are
Some examples of them
The main components of a computer system
The CPU
Main Memory – RAM and ROM

16. Plenary Questions – What is…
Hardware =
Software =
CPU =
Physical Components
Programs
The Brain

17. Past Exam Questions

18. RAM – So that users are able to make changes to the data they are working on/to store the program or data they are currently using (1)
ROM – So that programs/coding/software can be stored permanently/cannot be changed (1)
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21. Exam Paper Question