The Functional components or
units of the computer are those components that enable it to do the work of
data processing.
A computer has two
interacting components which work together to make it functional. Hence a
computer is only able to be of any use when the two functional components are
present and interacting with themselves. These components are:
·
The Hardware and
·
The Software
The Hardware Component:
Hardware are the physical component of a computer system
i.e. those parts of the computer that can be touched, felt and carried about.
The hardware component consists of a combination of different devices which
play specific roles in the operation of the Computer System.
These devices that make up the hardware are classified
into one of these four units below:
1.
Input Units
2.
Output Units
3.
Storage Devices
4. Central
Processing Unit (CPU)
Diagram of Component of Computer
Input Devices:
This is the medium through
which data and instructions (Programs) are communicated to the computer system.
They are usually such that they act as a gateway for receiving input usually in
user understandable form and convert it to machine form which the computer
understands.
Examples of input devices include:
Mouse, Keyboard, Punch Card, Microphone etc
Output Devices:
This is the medium through which the result of data processing
(information) and original data are communicated to the users.
Output devices work to
transform information processed in the computer which is in machine form to
human understandable form e.g. as text, pictures etc.
Example of output unit
include: Printer, Monitor (VDU), Speaker, plotter etc.
Central Processing Unit:
This is referred to as the “Brain” of the digital computer. This is because it
is there that all processing and refining of data takes place. It is made up of
three parts namely:
1. Main
Memory
2. Arithmetic
& Logic Unit
3. Control
Unit
All these components are integrated into what is called
System Unit.
Computer Memory
Data and program which are
stored in the digital computer’s memory are available in binary digits form of
0s and 1s (Zeros & Ones)
The actual memories of a digital computer are
classified into two parts:
a) Main
memory or Primary Storage or Temporary storage
b) Auxiliary
memory or Secondary Storage or Permanent Storage.
The Main Memory of a digital
computer is the original memory of
computer system all other forms are considered as secondary storage
device.
The primary storage of the
digital computer is divided into 2 parts ie the ROM and RAM
Read-only Memory (ROM)
1.
ROM is the acronym for Read – Only Memory
2.
ROM stores the data necessary to start the
computer and identify its component
3.
ROM is
non-volatile or persistent memory that holds permanent information, such as the
BIOS software that enables the components in the computer to communicate with
each other
4.
Data stored In ROM is not deleted when the
computer is switched off
5.
It cannot usually be deleted or overwritten
in the course of normal computer operations
Random Access Memory (RAM)
1.
RAM stores data while it is being processed.
E.g., RAM is required to run software while the computer is powered
2.
RAM, is
volatile or non-persistent memory, is a temporary memory store
3.
Data held in RAM is only stored while the
computer is switched on
4.
E.g., when you create a document (such as a
letter), the document is stored in your computer's RAM, until you save it to
disk
5.
RAM holds data required by the CPU, which
cannot store large amounts of data itself
6.
RAM is important because it enables the CPU
to get data quickly
7.
E.g., when a software application is started,
the data needed to run the program is copied from the main disk into RAM, where
the CPU can access it
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