1. Elements of a Computer System
Understanding Computers

2. What is a Computer?

3. Elements - Learning Objectives
All will be able to distinguish between hardware and software and identify Input, Output and Storage devices
Most will be able to explain what RAM and ROM are used for and distinguish between main memory and permanent storage devices
Some will be able to name and explain the three stages in the Fetch Execute Cycle

4. Hardware or Software? What is Hardware? What is Software?
Objects that you can touch, like a Music CD. For example:
Disks, disk drives, display screens, keyboards, printers, boards, and chips.
You cannot ‘touch’ software. Software refers to the programs that run on a computer, rather like the music playing on a CD.
Examples of software:
Windows, MS Word, MS Excel, Kodu and Logo.

5. Input, Output & Storage Devices
What is an output device?
What is an input device?
What is a Storage device?
An output device is a piece of computer hardware used display or output data which has been processed or stored in a computer.
Printer, Speaker.
An input device is anything can be used to enter data into a computer.
Keyboard, Mouse.
A storage device is used to permanently record or store data.
CD, Hard Drive.

6. What do each of these images represent. Are they hardware or software
What do each of these images represent? Are they hardware or software? Input, Output or Storage devices?
Students to try worksheet 1 stating what the input, output or storage device is and its use.

7. Computer Systems Look at Worksheet InputsProcessesoutputs
Determine the input, process and output in each case
Try to complete all the questions in the time given.
Try all questions on worksheet 2 in a given time limit. If not all questions are completed that is expected. Finish activity 1 is a minimum

8. The Central Processing Unit (CPU)
Understanding Computers

9. What are these Components?
Motherboard / CPU / RAM / graphics card / hard drive / SATA cable (connect mass storage devices)

10. The Components of a Computer
Central Processing Unit
(CPU)
Input
Output
Main Memory
Storage

11. Fetch – Decode – Execute Cycle

12. Fetch – Decode – Execute Cycle
Computer has a list of instructions in memory to carry out.
CPU Fetches top instruction from the list
Instructions is passed to Decoder to interpret
Decoder passes on the instruction
Instruction is Executed or carried out
CPU Fetches top instruction from the list…

13. Activity
Pupil 1 – holds instructions in the order they are to be processed
Pupil 2 – fetches instruction and gives to Pupil 3
Pupil 3 – decodes instruction and tells Pupil 4 what to do
Pupil 4 – executes the instruction
Can use pupils at the front of the class to demo how the FDE works. USE THE RESOURCE SHEET

14. Processor Speed How fast is your computer’s processor?
One cycle per second = 1 Hertz (Hz) = 1 instruction carried out each second
1 Kilohertz (KHz) = 1024 cycles per second
1 Megahertz (MHz) = 1,048,576 cycles per second
1 Gigahertz (GHz) = 1,073,741,824 cycles per second (Approximately 1 Billion!)
How fast is your computer’s processor?

15. RAM vs ROM RAM stands for Random Access Memory
ROM stands for Read Only Memory
Some data needs to be permanently held in memory, even when the machine is switched off
What does a computer do when you turn it on?
Where are these instructions held?

16. Task
Complete the work on worksheet 3 – MemoryStorage.

17. Finally….
Complete the plenary questions to show me what you have learnt today.
Available on the iTeach website