1.

Computer:

 The word computer has come from the word “compute” that means calculating.
 An electronic device which takes data as an input, store it, process the store data and
gives us the output according to the given input is called computer.
 The input and output data can be in different forms like text, images, audio and video.
 Thus it is an electronic device which performs arithmetic operations such as addition,
subtraction, multiplication and division at high-speed.
 The main objective of inventing computers is to process large arithmetic calculation.
 It can also be defined as it is a collection of hardware or software component to
accomplish many tasks.

2. Functionalities of a Computer

If we look at it in a very broad sense, any digital computer carries out the following five
functions −

Step 1 − Takes data as input.

Step 2 − Stores the data/instructions in its memory and uses them as required.

Step 3 − Processes the data and converts it into useful information.

Step 4 − Generates the output.

Step 5 − Controls all the above four steps.

Data:

Data can be defined as a representation of facts, concepts, or instructions in a formalized

manner, which should be suitable for communication, interpretation, or processing by human or
electronic machine.

1
Data is represented with the help of characters such as alphabets (A-Z, a-z), digits (0-9) or
special characters (+,-,/,*,<,>,= etc.)

What is Information?

Information is organized or classified data, which has some meaningful values for the receiver.
Information is the processed data on which decisions and actions are based.

For the decision to be meaningful, the processed data must qualify for the following
characteristics −

 Timely − Information should be available when required.

 Accuracy − Information should be accurate.
 Completeness − Information should be complete.

3. Characteristics of a Computer

Today computes are the backbone of every business of life. The most common properties of
computers which make them powerful machines are as listed below.

i. Speed
 A computer is a very fast machine. It can do a job in few seconds or minutes for
which a human being can take an entire year.
 A powerful computer is capable of performing 3 to 4 million simple arithmetic
per second.
 When we are taking about the speed of a computer, we do not talk in terms of
second or millisecond. The unit of speed is microsecond or nanosecond or pico-
seconds.
ii. Accuracy and reliability
 Accuracy of a computer is consistently high and the degree of accuracy of a particular
computer is dependent on its hardware design.
 A particular computer has same degree of accuracy for each and every calculation
performed in it.
 Reliability of a computer is extremely high. We can be completely dependent on a
computer to get fine and accurate result if the user had provided the right and
sufficient data.
iii. Diligence

2
  A computer is free from physical and mental tiredness, and lack of concentration.
 Thus it can work for hours without stopping and can give accurate outputs.
 If a computer is ordered to process ten millions of calculation then it will calculate
each with same speed and will provide output of each with same accuracy.
iv. Versatility
 A computer has its wide use of field. It can be used in commerce, daily life for
entertainment, scientific application as well as in education.
 As for example, one person who is creating a list of job applicants at one moment, at
the next moment he can use the same computer for booking tickets or after some time
he can watch movie or listen songs.
 So it is clear that a computer can be used for different purposes at different times.
v. High storage capacity
 A computer is capable of storing huge amount of data.
 We can store data of any size in a computer at any time and we can also retrieve it
any time very quickly.

4. LIMITATIONS OF COMPUTER
1. No I.Q.:

A computer has no I.Q. a computer can not perform tasks that a human can. The difference is
that it performs these tasks with unthinkable speed and accuracy. It has no intelligence of its
own. It has to be instructed to do and in what sequence. Hence only a user can decides what task
a computer will perform. It has no brain or intelligence regarding this.

2. No Feeling:

Computer have no feelings or emotions because they are machines. Based on our feelings, taste,
knowledge, and experience, we make our decisions in our daily life but it can not do these thing.
Their decisions are based on the instruction we give them in form of codes.

3. Prone to virus:
A virus can affect the performance of a computer. Sometimes they can destroy our computers.

4. Depend on electricity:

3
Computers cannot be operated without electricity.

5. APPLICATIONS OF COMPUTER
Today computers are used in various fields and these are as follows:

i. Entertainment:
Computers are used for playing games, listing music and watching movies. They are also
used to create movies and to make drawings.

ii. Education:
Today computers are used in school for teaching, doing mathematical calculations and
making computer projects.

iii. Banking:
In banking sector computers are used to store information of its account holders, it is also
used to keep record of cash deposit and withdrawal it is also used by the ATM.

iv. Railway stations and airports:

At railway stations and airports computers are used to check seat availability and for seat
booking. It is also used to see timings trains and airlines and to see the arrival and
departure of trains and airlines.

v. Business:
In business, computers are used to prepare documents, letters and to print them. They
also help to store records of all employees and other details of the business. It is also used
to send E mails to business colleagues.

vi. Designing:
Now computers are used to design magazines, newspapers, books and advertisements,
they are also used for design clothes, preparing blue prints of a buildings and for auto
mobile designing.

vii. Administration:
Computers are used in administration at a large-scale for handling of all kind of works of
administration.
6. Generations of Computer

4
  Generation in computer terminology is a change in technology a computer is/was being
used. Initially, the generation term was used to distinguish between varying hardware
technologies.
 Nowadays, generation includes both hardware and software, which together make up an
entire computer system.
 There are five computer generations known till date. In the following table, approximate
dates against each generation has been mentioned, which are normally accepted.

Following are the main five generations of computers.

S.No Generation & Description

1 First Generation

The period of first generation: 1946-1959. Vacuum tube based.

2 Second Generation

The period of second generation: 1959-1965. Transistor based.

3 Third Generation

The period of third generation: 1965-1971. Integrated Circuit based.

4 Fourth Generation

The period of fourth generation: 1971-1980. VLSI microprocessor based.

5 Fifth Generation

The period of fifth generation: 1980-onwards. ULSI microprocessor based.

7. Types of computer

5
Computers can be broadly classified by their speed and computing power.

S.No. Type Specifications

1 PC (Personal A personal computer (PC) is a digital device designed for personal

Computer) purposes, such as working, studying, gaming, and browsing the internet.
A typical PC consists of several hardware components, such as a
motherboard, processor, memory, storage, and input/output devices, such
as a monitor, keyboard, and mouse.

2 Workstation A workstation computer is designed for technical or scientific

applications. It consists of a fast microprocessor, with a large amount of
RAM and a high-speed graphic adapter. It is a single-user computer. It is
generally used to perform a specific task with great accuracy.

3 Supercomputer Supercomputers are designed such that they can process a huge amount
of data, like processing trillions of instructions or data just in a second.
This is because of the thousands of interconnected processors in
supercomputers. It is basically used in scientific and engineering
applications such as weather forecasting, scientific simulations, and
nuclear energy research. It was first developed by Roger Cray in 1976.

4 Tablets and Tablets and Smartphones are the types of computers that are pocket
Smartphones friendly and easy to carry is these are handy. This is one of the best use of
modern technology. These devices have better hardware capabilities,
extensive operating systems, and better multimedia functionality.
Smartphones and tablets contain a number of sensors and are also able to
provide wireless communication protocols.