Download Worksheet-1 Answers

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Worksheet-1 Answers
Answer the following questions:
A. Explain the History of Computers before 1940.
Use of ABACUS from 400 BC to AD 1600
• The Abacus was the first mechanical device used by people for calculations.
• It had a wooden frame with beads sliding on wires.
• The wooden part held the wires tightly.
• Calculations were carried out by moving the beads according to the set rules.
• There were different types of Abacus used in different countries such as Roman
Abacus, Asian Abacus, wooden abacus, etc.
Napier’s Bones in Early 1600
• Napier’s Bones, an abacus, was invented by John Napier a Scottish
mathematician and scientist—in 1617.
• It helps you to multiply, divide and find square roots. There are 9 different
‘bones’ or strips with numbers. You may need several copies of each strip for
calculation.
Pascaline in 1642
• Blaise Pascal invented the first automatic calculator in 1642.
• It used to perform mathematical calculations up to hundreds
and thousands.
• It consisted of a rectangular box containing moveable wheels.
• It was run by turning gears and wheels.
• These days the same principal is utilised in
taxi meters, electricity meters, petrol pumps, etc.
Difference and Analytical Engine by Charles Babbage
In 1822, Charles Babbage, a British mathematician, invented a working model of
mechanical computer called the Difference Engine.
• He wanted to create a machine which gave accurate solutions to mathematical
tables.
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• The Difference Engine had five different units which were used to input,
store, calculate, output and control.
• Later, in 1833, Charles Babbage invented another complex working model
known as the Analytical Engine.
• The Analytical Engine was a revolutionary device which made him famous as a
computer pioneer.
• It was intended to perform any arithmetical calculation using punched cards
that would deliver the instructions, as well as a memory unit to store numbers
and many other basic functions of today’s computers.
• He was not able to complete the model of the Analytical Engine during his
lifetime. It was completed after his death in 1871. Today’s modern computer
work on the same principal as that of the Analytical Engine.
• Charles Babbage, therefore, is known as ‘father of modern computer’.
Dr. Herman Hollerith
• Dr. Herman was an American statistician who invented a machine called the
Tabulating machine.
• This machine was, for the first time, able to read data, process it and gave the
desired output.
• The input in this machine was given through punched cards.
• Punched cards were also used to record data and store data or information.
• This machine, for the first time, was run by electricity.
• He established a tabulating machine company which later grew as
International Business Machines (IBM).
Some of the other inventions which have contributed to the making of modern
computers are as follows:
MARK-1
Howard H. Aiken, an engineer in IBM, constructed the first automatic sequence
controlled calculator—the MARK-1 in 1944.
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ENIAC
Electronic Numeric Integrator And Calculator (ENIAC) was the first general
purpose electronic digital computer invented by John Mauchly and J. Presper
Eckert in 1946.
EDVAC
Von Neumann, who was the consultant for the ENIAC machine, formulated a
plan with Mauchly and Eckert for a new computer system known as Electronic
Discrete Variable Automatic Computer (EDVAC) which was now used for storing
program and data.
UNIVAC 1
Later, the inventor of ENIAC and EDVAC machines, i.e., Mauchly and Eckert
invented the first commercial electronic computer. It was also the first computer
system to handle both numeric data and text data.
B. Differentiate between first and second generation of computers.
First Generation
Second Generation
1.They used vacuum tubes.
1.They used transistors.
2.It started from year 1940-1956.
2.It started from 1956-1964.
3.The system supported machine
language only.
3.The system supported machine &
Assembly language.
4.They were very large in size, had
4.They were smaller, faster, cheaper
small internal storage and were very
and more efficient than the first
expensive.
generation computers.
C. Explain the three characteristics of a computer.
Characteristics of the computer system are:
Speed
The computer works at an amazing speed. It takes only a few seconds for
completing a task which may take hours to complete by a normal human being.
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You will be surprised to know that computers can perform millions (1,000,000) of
instructions and even more per second.
Reliability and accuracy
A computer has maximum accuracy rate. It never commits mistakes in processing
data, i.e., it is reliable than humans. The errors in computer are due to human and
inaccurate data provided by humans.
Storage capacity
The computer has an in-built memory where it stores large amount of data. You
can also use secondary devices to store data such as floppy Drive, CD, DVD, Pen
Drive, etc., which can be kept outside your computer and is easy to carry.
D. Differentiate between analog and digital computer system with example.
Analog computers
Digital computers
1.An analog computer (spelt analogue 1.Digital Computer measures physical
quantities by counting, such as
in British English) works on
addition, subtraction, division and
continuous signals.
multiplication.
2.Analog computer can perform
several mathematical operations
simultaneously.
3.These computers use continuous
variables for mathematical
operations and utilises mechanical
or electrical energy model the
problem being solved.
2.They use digital circuits and
are designed to operate on two
states, namely bits 0 and 1. They
are analogous to states ON and
OFF. Data on these computers is
represented as a series of 0s and
1s.
3.Digital computers are suitable for
complex computation and have
higher processing speeds. They are
programmable. Digital computers
are either used for general purpose
or for special purpose.
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E. Explain the computer system on the basis of size and processing capabilities.
On the basis of size and processing capabilities computers can be broadly divided
into four parts:
Supercomputers
These systems are generally very large in size, very expensive and have high
processing power. These types of computer systems are rare to find as they
are neither used as a PC in homes nor in colleges, etc. It is basically used by
governments agencies specially for their different calculations and complex
scientific applications such as aerodynamic design simulation, processing of
geological data in weather forecasting and also can be seen in space research
laboratories and nuclear power stations. They require special highly qualified staff
to operate them.
Mainframe Computers
They are usually slower, less powerful and less expensive than
supercomputers. They have large memory capacity and allows networking
up to 100 terminals. Networking is a technique that allows many people
at terminals, to access the same computer at one time which is called
time sharing. Mainframes are used by banks and many business to update
inventory, etc. Mainframe computers can support hundreds or thousands of
users, handling massive amounts of input, output and storage. Mainframe
computers are used in large organisations where many users need access
to shared data and programs. They are also used as e-commerce servers,
handling transactions over the Internet.
Minicomputers
They are smaller than mainframe computers, have higher processing
speed than the lowest category computers but are slower than super and
mainframe computers. It is versatile and portable because of smaller size than
supercomputers and mainframe computers. It generates a lot of heat. It is
generally easier to use. It usually has multiple terminals and may be used as
network servers and Internet servers.
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Microcomputers or Personal Computers
These are the latest technology in computer to reduce the size of computers
hence, the development of personal computers (PCs) indicating that an individual
can now have a computer at home and small offices. They are durable, cheap, fast
and generate less heat.
Tower Computers
These are computers that are positioned vertically on their stand. They are
not usually very portable. There are two types of tower computers, namely:
Full tower: This type of tower computers carries or come along with
speakers on the System Unit.
Desktop computers: These are microcomputers that lie horizontally on their stand
or on a desk (desktop). In most offices, the desktop computer (CPU) is placed on
a desk or below the table while the monitor rest on top of it.
Laptop Computers
These are very portable computers designed to be supported on the lap and with
varying sophistication. The laptop computers are more portable when compared
to the desktop or tower computers.
Notebook Computers
These are very portable computers usually notebook or textbook sizes. The
notebook computers are a little smaller than the laptop computers but perform
the same type of task.
Palmtop Computers
These are very small computers designed to be operated on the palm like mobile
phone, calculator, organiser, etc. This type of computer is among the smallest size
of computer.
F.
Write a short note on Charles Babbage and his contribution to modern world.
• In 1822, Charles Babbage, a British mathematician, invented a working model
of mechanical computer called the Difference Engine.
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• He wanted to create a machine which gave accurate solutions to mathematical
tables.
• The Difference Engine had five different units which were used to input, store,
calculate, output and control.
• Later, in 1833, Charles Babbage invented another complex working model
known as the Analytical Engine.
• The Analytical Engine was a revolutionary device which made him famous as a
computer pioneer.
• It was intended to perform any arithmetical calculation using punched cards
that would deliver the instructions, as well as a memory unit to store numbers
and many other basic functions of today’s computers.
• He was not able to complete the model of the Analytical Engine during his
lifetime. It was completed after his death in 1871. Today’s modern computer
work on the same principal as that of the Analytical Engine.
• Charles Babbage, therefore, is known as ‘father of modern computer’.