Class XI - Introduction and Evolution of Computers

Introduction and Evolution of Computers

1.1 Definition of Computer

The word computer is derived from the latin word computare which means to calculate.
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations.
It can also be defined as an electronic digital and automatic machine which takes input from the user, processes it, stores if necessary and gives output in desired form.

Characteristics / Features of Computer

Speed

Computers work at a very high speed.
It can do calculations at extremely high speed in fact with the light of speed.
It can perform millions of instructions in a fraction of second like millisecond, microsecond, nanosecond and picoseconds.
The speed of a microprocessor is usually measured in Millions of Instructions Per Second. (MIPS)

Accuracy

Computer gives accurate processing results.
It does not make error itself.
Error can occur in computer due to inaccurate data or instructions fed by human or end users.
So, If a wrong input is given, the output will also be wrong, which is known as Garbage In Garbage Out. (GIGO)

Automation

Computer is an automatic machine, capable of functioning automatically, once the appropriate set of instructions (program) and data are provided to the computer. Diligence
Computer can perform task repeatedly again and again without getting tired and bored.
A computer is free from tiredness, weakness, lack of concentration and monotony. It can work continuously for long hours with the same speed and accuracy.

Versatility

Computer is a versatile machine which can perform varieties of task depending upon the different programs fed to it.
It can perform operations ranging from simple mathematical calculations to highly complex and logical manipulations.
Some of the applications areas of computers are in education, business, bank, office, hospitals, astronomy and other many activities.

Reliability

Computer can perform lots of work without any mistakes and tiredness.
That’s why they are widely used every where because of their reliability.

Storage

Computer can store large amount of data.
It has in built and auxiliary memory i.e. primary and secondary memory.
Any data stored in the memory can be retrieved at any time and at very high speed.

Word Length

Word length or word size refers to the number of bits that CPU manipulates at one time.
A digital computer operates on binary digits 0 and 1.
Computer word lengths are 8, 16, 32, or 64 bit and in super computer 128 bit is used.
The longer the word length, the more powerful the computer is. Non – intelligent
Computers cannot do even the simplest work, if the data or instruction are not provided by the user.
It is called brainless idiot servant of human that performs massive task as according to the given instructions.

Capabilities and Limitations of Computer

Capabilities

It produce 100% accurate outputs, if correct data and instructions are provided.
It performs difficult and complicated calculations at a high speed.
It is capable of storing data and retrieving whenever it is required.
It can perform repeated task with the same speed and accuracy without getting tired and bored.
It can do tasks that are critical and dangerous and hazardous to human being.

Limitations

It is the non-intelligent machine (dumb machine). It cannot think and give the right decisions as human beings.
It cannot be operated without battery or electricity.
It cannot memorize and recall as needed. It only stores data in secondary device. • It requires instructions to perform task.
Failure in devices and wrong information by users makes it unreliable.

Advantages and Disadvantages of computer

Advantages

It is faster than human being.
It is always accurate and reliable.
It is versatile i.e. masters in all types of work and fields like education, hospitals, banks etc.
It can be used for communicating among many users.
It never feels exhausted and tired.

Disadvantages

It can be used for computer crimes like hacking, creating and spreading viruses etc.
Repair and maintenance is required frequently.
Skilled manpower is required to work in the computer.
It is still expensive and every people cannot afford it. • People are becoming too much dependent on computers.

1.2 Application of Computers

Education

Computers are being used increasingly in teaching and learning at all levels, result processing, notes preparation etc.
It has been proved that learning with computers has been more successful that is why numerous forms of teaching methods have been introduced which enhances the knowledge of student.
In educational system, computer is used as teaching aids, information resources and computing and research means or tools. When computer is used as teaching tool, it is referred as CAI (Computer Assisted Learning).

Office

Computers are used in office to carry out its day to day activities.
They are used in preparing reports, letter, notices, memorandum etc. it helps user in preparing, storing, retrieving and displaying text.
In offices accounting, billing, preparation of payrolls, data analysis, auditing etc are also performed. Word processing and spreadsheet packages are extensively used.

Business

Many business companies, either large or small use computers to help in the control of daily activities like employee record, payroll processing, general ledger, record of stock, record of bills receivable and payable.
In departmental store POS (Point of Sale) terminal is used to process sales transaction. It updates sale records and inventory control of the departmental store.

Communication

Computers are massively used in communication.

It is done by emails, chat, online conferencing, e-fax.
Communication had been made cheaper and quicker by means of communication like through email person can send messages from one place to other within a second i.e. it saves time, cheap and so on.

Bank

Computers are used in banks for various tasks such as handle transaction, maintain ledger, issue fixed deposit receipt, provide online services to customers etc.
Bank use cash dispensing machine to handle cash as well as MICR (Magnetic Ink Character Reader) to process large volume of cheques.
Use of ATM (Automated Teller Machine) has ease to withdraw money at any time and any place in a quick manner.

Hospital

Computers are used in hospitals to help doctors in diagnosis, getting information on patient diseases, required treatments and keeping patient’s record.
Doctors can get information from distant data banks and expert system. An expert system is a program based on the expert knowledge of specialists.
They supply the detailed information such as symptoms, medical history and test results to get the information from expert system.
They can discuss with colleagues using teleconferencing.

Industry

Computers are used in industries for automatic control of machines, process, measurement and display of electrical and physical quantities. Eg. Automatic control of temperature of a heating system, speed of a motor, voltage of generator, pressure of boiler etc are all microprocessor based computer system.
If any fault on any part or the system occurs, it immediately alarm and disconnect the faulty part from the healthy part of system.

Military

Computers are widely used in defense purpose.

Smart weapons are being used in military operations. Modern tanks, missiles, fighter planes etc employ computerized control system.
Guided missiles or fighter planes are flying faster and turn more quickly as compared to manned aircraft.
They can fly in dangerous zones without the risk of pilot’s life.

Desktop Publishing System

Computers use desktop publishing package which is more powerful than word processing packages.
It includes computer and a number of peripherals with powerful software to produce complete page layouts with pictures and text printed in a variety of attractive ways. Such pages are used in book design, manuals, bulletins, newsletters etc.

Aviation

Computers stores all necessary information regarding ticket reservation, flight number, flight route, distance, number of seats available for each flight, ticket fare etc.
It is also used in air traffic control system to control landing and take off of airplanes to minimize the accidental risk and to increase the number of flight in an airport.
Computer is used to control RADAR system and other communication devices.

1.3 Historical Evolution of Computer

Abacus

Abacus is the first mechanical calculating device which was invented around 3000 BC.
It had its origin in ancient china, Greece (Roman), Egypt and Great silky road. It is made up of rectangular frame divided into two parts separated by mid bar.
The upper part which is called heaven consists of two beads and value of each bead is equal to five and the lower part which is called earth consists of five beads and value of each bead is one.
Calculations are performed by manipulating beads.
Each abacus consists of nine or eleven or thirteen beads.

Napier’s Bone

It was invented by John Napier, a Scottish Mathematician, in the year 1617 AD.
It consists of rods which were made of bones on which numbers were carved and painted.
John Napier played an important role in the development of logarithm. It was specially used for calculations of complex multiplication.

Slide Rule

It was invented by William Oughtred, an English Mathematician, in the year 1620 AD.
It consists of two marked rulers, one of which could slide over the other and once properly aligned would give the user the required product or quotient.
It is the first analog device and it is based on principle of logarithm.

Pascaline

It was invented by Blaise Pascal, a French Mathematician, in the year 1642 AD.
It has dials to deal with numbers up yo 9,999,999.
It was made with the arrangement of wheels, gears and windows for display of numbers.
It could perform addition and subtraction and not used for division and multiplication.
He invented this machine to assist his father who was a tax collector.

Stepped Reckoner

It was invented by Gottfried Wilhelm Von Leibniz, a German Mathematician, in the year 1671 AD.
It could perform addition, subtraction, multiplication, division and evaluate square roots by a series of stepped addition.
The centerpiece of this machine was its stepped drum gear design.

Jacquard’s Loom

It was invented by Joseph Marie Jacquard, a French man, in the year 1802 AD.
It was the first machine to use punched card with punched holes to control the weaving to produce beautiful pattern.
Its function depends upon the presence and absence of holes on the punched card.
It paved the way for the modern storage mechanism on punched card and the use of binary number system.

Difference and Analytical Engine

Charles Babbage, an English Mathematician, in the year 1822 AD invented Difference Engine.
It can solve different equations and calculate various mathematical functions.
This project could not be completed due to lack of funds. In 1833 AD, he invented Analytical Engine. This machine had four major units:
The store (equivalent to memory)
The mill (equivalent to CPU)
The input section using punched card. The output section using punched card.
Unfortunately, his work could not be completed.
His efforts guided a number of principles which have been shown to be fundamental to the design of today’s modern computers. That’s why he is also known as the Father of the Modern Computer.

Lady Augusta Ada Lovelace

An English Mathematician (daughter of English Poet Lord Byron) carried forward the work of Charles Babbage.
She was the first computer programmer.
She developed several programs for performing mathematical calculation on the Analytical Engine.
One programming language ‘Ada’ was named after her.

George Boole

George Boole developed Boolean Algebra (algebra of logic) in 1954.
It is the basis of design and implementation of digital system including digital computers.
It laid the foundation for modern computers which use binary number system.

Tabulating Machine

It was invented by An American inventor Dr. Herman Hollerith in the year 1886 AD.
It used punched cards for input, output and instructions.
This machine was used by American Department of Census to compile their 1890 census.
In 1896, he founded the tabulating machine company which was renamed as IBM (International Business Machine) later.

Electro Mechanical Era Mark I

It is considered to be the first electrical mechanical calculator.
It was also known as IBM ASCC (Automated Sequence Controlled Calculator).
It was developed by Howard H. Aiken of Harvard University with his staff in 1944.
It was capable of performing addition, subtraction, multiplication and division.

Some of its features are:

It was 51 feet long, 8 feet height and 3 feet wide and weighted nearly 5 tons.
It used about 18 thousand vacuum tubes as main memory device with 7 lakhs 50 thousands parts. It consumed huge amount of power and generated lot of heat during operation.
The input device was punched card.
The time taken for average multiplication and division was about four and eleven seconds respectively. The results were printed at the rate of one result per five seconds.

ABC (Atanasoff Berry Computer)

It was the first electromechanical digital computer.
It was developed by John V. Atanasoff and Clifford E. Berry in 1937 – 1942 at Lowa state University.
It used punched card as secondary storage.
It used 18000 vacuum tubes and other 45 valves for internal logic and capacitors for storage of electrical charges.
It introduced the idea of binary arithmetic and logic circuit.

ENIAC (Electronic Numerical Integrator and Calculator)

It was designed by John Mauchly and J.P. Eckert in 1946.
It was the first popular general purpose electronic digital computer.
It contains 17468 vacuum tubes, 70,000 resistors and weighted about 30 tons.
It consumed 160 kilowatts and generates huge amount of heat and needed to be water cooled.
It took 200 microseconds for addition and 3 milliseconds to perform 10 digit multiplications.
It used decimal number system instead of binary number system.

EDSAC (Electronic Delay Storage Automatic Computer)

It was designed by Maurice Wilkes at Cambridge University in 1949.
It was the first stored program computer.
Input and output were performed by paper tape.
It could do 700 additions and 200 multiplications per second.
It contains 3000 vacuum tubes and operated on 30 kilowatts.
It used a mercury delay line storage system.

EDVAC (Electronic Discrete Variable Automatic Computer)

It was designed by J. Mauchy and J.P. Eckert at Pennsylvania University and completed in 1950.
It included a stored program, a central processor and a memory for both data and programs.
He proposed the computer to use binary number system instead of decimal number system.

UNIVAC I (Universal Automatic Computer – I)

It was designed by J.P. Eckert and J.Mauchly in 1961.
It was the first general purpose electronic computer dedicated to business applications i.e commercial use.
It consists of magnetic tape for data input and output.
It was 8 ft. high, 15 feet long and weighted 5 tons.

1.4 Generation of Computers

The phases or stages of computers in which different technologies were used for its development and performance.

The development of computers in different time period is called generation of computer.

First Generation computer (1940 – 1956)

Vacuum tubes were used as the main electronic component.
Magnetic drum were used for primary storage medium.
Magnetic tapes were used for secondary storage memory.
Input was based on punched card and paper tape and output was displayed as printouts.
They were slow in operation and they perform a task in milliseconds.
They were very large in size and required a lot of space for installation.
They emitted large amount of heat because they used lots of vacuum tubes.
They were very expensive to operate as well as they were prone to frequent failure and also they were unreliable.
Machine language was used to perform operations and they could only solve one problem at a time.
ENIAC, ADVAC, EDSAC, UNIVAC are the examples of First Generation of computers.

Second Generation of computer (1956 – 1963)

Transistors were used as the main electronic component.
Magnetic core was used for primary storage medium.
Magnetic tapes and magnetic disks were used for secondary storage medium.
Input was based on punched card and paper tape and output was displayed as printouts.
They were faster and could perform tasks in microseconds.
They were smaller, more reliable and powerful than the first generation computers.
They generate less heat and were less prone to failure. 8. Assembly language was used to program these computers.
High level programming language like ALGOL, COBOL, and FORTRAN were also being developed.
IBM 7000, NCR 304, IBM 650, ATLAS, MARK-III, IBM 1401 etc are the examples of 2nd generation computer.

Third Generation Computer (1964-1971)

Integrated circuits were used as the main electronic component.
Semiconductor memory was used for primary storage medium.
Magnetic disks were used for secondary storage medium.
They used keyboard for input device and monitor as output device for the interaction with the users.
Processing speed was increased and measured in nanoseconds.
They were smaller in size and cheaper as well as more reliable and better in performance.
They used operating system which allowed to run many application at one time.
They were programmed in high level language (FORTRAN, BASIC).
Power consumption of ICs were less than that of transistor resulting to reduced power consumption.
PDP-8, PDP-11, ICL 2900, IBM 360, IBM 370, etc are the examples of 3rd generation computer.

Fourth Generation Computer (1971 – Present)

Microprocessor is used as the main electronic component.
Semiconductor memories are used for internal memory.
Magnetic disk and optical disk are used for secondary memory.
Processing speed are increased and measured in picoseconds.
They are more versatile and diligence.
They are the cheapest among all the generation.
Rise of personal computers.
Many more high level language like pascal and C have been introduced.
They became more powerful, compact, reliable and affordable.
IBM PC, Apple Macintosh, HP3000, SUPERBRAIN etc. are the examples of 4th generation of computers.

Fifth Generation of Computers (Present and Beyond)

Biochip will be used as the main electronic component.
They will have artificial intelligence and can perform parallel processing.
They will be able to understand natural language.
They will be capable of thinking themselves as well as to use intelligent program.
They will have multi processors and parallel processing capability.
They will use super conductor technology
Important fields of research in AI are automatic programming, pattern recognition, game-playing computers.
Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come.
Hot pluggable features in the device so that any time the device can be connected and disconnected.
They will use ULSI.

Artificial Intelligence

It is a branch of computer science that refers to the use of computer in such a way that they are able to reason and draw, recognize voice and having language processing ability is called AI.

Characteristics of AI

It is man made and its level of activity depends on the programming capability.
It has the potential to extend problem solving ability of a manager beyond his/her normal capabilities.
It is a mechanism that is not subject to human feelings like fatigue, worry etc.

NOTE: 1 transistor could do the work of 1000 vacuum tubes. IC is also known as semiconductor chip and it contains number of transistor. Microprocessor contains millions of transistors.

Computer Speed and Measurement Speed

Every microprocessor contains a system clock.
The system clock controls how fats all the operations within a computer take place.
The interval between successive pulses i.e. their rate of repetition is called clock speed.
In computer clock rate is measured in mega hertz (MHz), where 1 MHz=1 million pulses per second. Now a days computers come with stunning clock speed of

Giga Hertz. (GHz)

The execution speed of computer is measured in terms of MIPS (Millions of Instructions Per Second). 0.5 MIPS=500,000 instruction per second.
High speed computer and workstations perform at 200 MIPS and even higher

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Class XI - Introduction and Evolution of Computers | Computer