1. The Riverside School

2. What is a Computer ?
 A ‘compute’-r is a device which ‘compute’-s
 to compute = to calculate, to make sense

3. Parts of a Computer
 There is no such particular part known as the
‘computer’
 The ‘computer’ is a collection of many parts
working together
 The computer is divided into two categories –
mainly known as ‘hardware’ and ‘software’

4. Hardware & Software
 The physical parts of a computer which you
can see and touch are collectively called the
‘hardware’
 E.g. keyboard, cd-rom drive
 The programs or instructions sent to the
hardware are called the ‘software’
 E.g. Microsoft Word, Internet Explorer

5. The external hardware

6. Functions of the hardware
 The computer hardware can again be divided
into ‘input’ and ‘output’ devices
 An Input device feeds data into the computer
 E.g. keyboard, mouse, scanner
 An Output device displays or receives data
from the computer
 E.g. monitor, printer

7. INPUT – process - OUTPUT
 Any activity on a computer is an
input - process - output sequence
 E.g.
Sugarcane >>>> Factory >>>> Sugar
 Question (input) add 5 + 2
------------------------------------------process-----
----------------------------------------------Answer
(output) = 7

8. Data & Instructions
A computer requires data and instructions to
work on.
E.g. to print the name and address of a person,
the following data has to be provided:
Name of Person, Address of Person
the instruction given to the computer will be:
Print name and address of Person
Input – name and address
-process of reading data-
Output – Printout of name and address

9. System Unit
The system unit is the
main part of a computer
All other parts of the
computer connect to the
system unit using cables

10. Parts of the System Unit
CPU
 The CPU is the Central Processing Unit of the
computer
 It is also known as the ‘processor’ in the
computer
 The CPU is the ‘brain’ of the computer which
computes calculations and instructions
received from the RAM

11. Central Processing Unit
 CPU is divided into 2 parts
 Control – it manages the complete
processing activities
 Arithmetic & Logical Unit (ALU) – does all the
arithmetical and logical calculations

12. Parts of the System Unit
Memory
All data or input instructions must be first
stored into the memory to be processed by
the CPU
The types of Memory are:
e) Primary (internal) Memory
f) Secondary (external) Memory

13. Memory is also referred as Storage
Primary (internal) Storage
ROM – Read Only memory
Contains permanent computer information. It
cannot be used for storing data. Data in ROM
Memory does not get lost even if the
computer is switched off.
RAM – Random Access Memory
Contains temporary data. The contents inside
RAM get erased as soon as the computer is
switched off.

14. Secondary (external) storage
Internal Storage (ROM & RAM) is always
limited. In everyday computer use, all
programs or data cannot be stored
permanently stored into internal memory.
To store data permanently, external memory
is used.
E.g. tape disc, hard drive, pen drive, floppy,
CD, DVD

15. Types of Storage
Each computer has one or more Disk Drives.
Disk drives – or disks - are devices which
store information on a metal or plastic disk.
The disk preserves the information even
when your computer is turned off.

16. Types of Storage
Hard Disk
The hard disk is a large capacity disk which is
normally located inside the system unit.
On the inside, it is a stack of platters with a
magnetic surface. Because a hard disk can
store huge amounts of data and information,
it usually serves as your computer’s main data
storage.

17. Types of Storage
Floppy Disk
Floppies or diskettes, are less popular than
they used to be.
They store very little information compared
to CD’s or DVD’s and are easily damaged in
daily use.
The inside is a thin flexible material whereas
the outside is hard plastic.

18. Types of Storage
CD or DVD disk
CD – Compact disk
DVD – Digital Versatile Disk
CDROM – Compact disk Read only Memory
It’s main use is for loading new programs
onto the hard disk.
A CD Drive uses lasers to read information
from a CD or to write information onto a CD.
A DVD is similar to a CD but has larger
capacity compared to the CD.

19. Assignments
 Give one example of the input-process-
output activity
 Describe the uses of a Pen Drive. How is it
different from the other disks – hard disk,
floppy disk and CD ?

20. Parts of the System Unit
Motherboard
The motherboard is the
primary circuit board in
the computer.
Its function is to provide electrical and
logical connections for all the components of
the computer to communicate with each
other.

21. Motherboard
Motherboard or Mainboard include the
following:
 Socket for connecting the CPU
 Slots for connecting the RAM
 Slots for ‘expansion cards’
 Power connector
 Connectors for input & output devices

22. Parts of the System Unit
Expansion cards or expansion
boards are small circuit
boards that can be connected
onto the motherboard.
Expansion cards can consist of graphic cards,
sound cards, network cards or any other
internal or external connectivity.

23. Parts of the System Unit
Power Supply
It’s function is to power up the computer.
It provides power to the motherboard, hard
disk, cd-rom drive, floppy drive and any other
component that requires power within the
System Unit.

24. Parts of the System Unit
A CD-ROM or DVD-ROM Drive is used for
reading data from a CD or DVD disk.
A CD-RW (re-writeable) or DVD-RW drive is
used for writing data to a blank CD or DVD
disk.
A floppy drive is used for reading or writing
data onto a floppy disk.
All drives contain mechanical parts and
require power for a read-write operation.

25. Types of Computers
 Super Computers
Super Computers are most powerful
computers. They can process huge amounts
of data very quickly.
 Mainframe Computers
Mainframe computers are less powerful than
super computers. They can handle several
amounts of input, output and storage.

26. Types of Computers
 Workstations and Server Computers
A server computer or server, is basically
intended to run for an extended time, under
heavy workload and is often unattended by
users. Servers contain faster or more
processors, more RAM and more or larger
hard disks compared to the desktop
computer.

27. Types of Computers
 Personal Computers or PC
They are smaller computers normally found
at home, office or classroom. PC is more
widespread because of it’s size and affordable
price. The laptop is also a personal computer
which is just smaller in size.
 PDA or Handheld Computers
Personal Digital Assistants are also called
pocket computers which can fit into the
pocket and are used for emailing, word
processing, video recording, etc.

28. Assignments
 Bring any one part of the system unit from
home and provide a brief description for it.
 Describe the different types of computer
monitors that we have at school.
 Describe the different types of computer
printers that we have at school.