1. 4. Computer system

2. Parts of Computer

3. Parts of Computer

4. Parts of Computer

5. What is Computer System?
Computer Systems are made up of many different parts for e.g. hardware, software, processors, memory, etc.

6. Hardware
Any physical parts of a computer that you can touch, see and pickup.
Examples – monitor, keyboard, mouse, disk drives, printer, scanner and speakers.

7. Software
The applications and programming instructions needed to make the computer hardware do useful work.
System Software – Operating systems, Utilities, User Interface
Application Software
Word Processors e.g. MS Word
Spreadsheets e.g. MS Excel
Databases e.g. MS Access

8. Differences between Hardware and Software

9. Peripherals
Any device which connects to the computer and exchanges data with the CPU.
Include all of the computer’s input and output devices.
Examples – monitor, keyboard, external modem.

10. Central Processing Unit (CPU)
‘Brain’ of the computer.
Where all the searching, sorting, calculating and decision making takes place.
The speed of the CPU is measured in Megahertz (MHz) or Gigahertz (GHz).
1 MHz = One million instructions per second.
1 GHz = One billion instructions per second.

11. CPU Components CPU Consists of three main parts: Control Unit
Immediate Access Store
Arithmetic and Logic Unit

12. The Control Unit Three main jobs:
It controls and monitor the hardware attached to the system.
It controls the input and output of the data.
It controls the flow of data within the CPU.

13. The Immediate Access Store
Holds the data and programs at that instant by the Control Unit.
The CPU reads data and programs kept on the backing storage and stores them temporarily in the IAS’s memory.

14. Arithmetic and Logic Unit
This is where the computer processes data either by manipulating it or acting upon it.
It consists of two parts:
Arithmetic part – it performs the calculation on the data e.g = 5
Logic part – deals with logic and comparison for e.g. it works out if one value is greater, less than or equal to another.

15. Motherboard The central circuit board of your computer.
All of the components and peripherals are plug into it.
Houses the ROM chips which stores the BIOS instructions.
Relay information between the components and peripherals.

16. Disk Drives Purpose is to read data from a storage device.
The most common disk drives:
Hard disk drive
Removable disk drive
Floppy disk drive
Zip drive
CD drive, DVD drive

17. Memory
Two main types: Random Access Memory (RAM) and Read Only Memory (ROM).

18. Cache Memory
A special type of computer memory which can be accessed much faster than RAM.
Volatile i.e. when the computer is shut down, the data stored there is lost.