What is a Computer?

What is a Computer?

 

A computer is an electronic machine that is useful to process data, converting the data into information.

OR

A computer is an electronic device that can interpret and execute programmed commands for input, output, computation, and logic operation.

Computers may be technically complex, but they are conceptually simple.

Historical Background

From the ‘antiquity’ man has invented devices to assist him in calculating and processing data. The biggest milestone in the achievement of mankind has been the discovery of numbers. In early ages, man used pebbles and stones for counting purposes. The discovery of the “0 or zero” gave real boost to the development of the “number system”. Later, the Egyptians introduced symbols for ten and powers of ten in recording number in the year 3400 B.C.

 

The history of computers spread out for more than five thousand years of computer development and intelligence. The age of computer divided into three major periods, which are known as:

        The Dark Age (5000/3000 B.C. to 1890 A.D).

        The Middle Age (1890 to 1944).

        The Modern Age (1994 to till).

The Dark Age (5000/3000 B.C. to 1890 A.D)

The Dark Age of computers is from 3000/5000 B.C. to 1980 A.D. The biggest milestone in the achievement of mankind has been the discovery of numbers. Before ages, people used pebbles and stones for counting purposes. The discovery of zero gave a real boost to the development of the numbering system.

 

Abacus (3000 B.C).

 Probably developed in China. The “ABACUS” or “COUNTING FRAME” is the frame with beads strung on wires or rods. Abacus is a mechanical device that was used for counting. Addition, subtraction multiplication, and division. It was usually a wooden frame having 13 parallel wires on which a number of beads could slide, different wires were assigned as units, tens, hundreds, thousands and so on, represented by the number of beads on the particular. The structure is divided into two parts. The upper part is called the Heaven and the lower part is called Earth. The abacus is still widely used in the orient. An adept abacus operator can calculate faster than a clerk using a desk calculator.

 

Napier’s Bones (1617).

 John Napier, “Scottish Mathematician” described this device in the year of his death. The process of multiplication and division became very simple with the help of logarithms. Napier’s idea of logarithm gave birth to another very useful and commonly used calculating which is known as Slide Rule. His bones are a set of eleven rods with numbers on them in such a way that by simply placing the side of the rod by side products and quotients of large numbers can be obtained.

 

Oughtred’s Slide Rule (1632).

The slide rule was invented in 1632 by an English Mathematician William Oughtred. He is also known for inventing the multiplication symbol denoted by X, A slide rule is a very useful, simple and handy device and till the last decade, it was extensively used in many countries by engineers, scientists and accountants.

Pascal’s Calculator (1642).

 The first successful mechanical calculator its name is “adding machine” was constructed by a great French physicist and mathematician Blaise Pascal at the age of 18 years in 1642. this machine was restricted to only addition and subtraction. The device registered number by rotating the Cogwheel gear by one to ten steps with a carryover jacket to operate a next higher-digit when the given cogwheel exceeded then units. “Pascal’s Machine” or “adding machine” was improved by a Philosopher and mathematician Leibniz who’s Wheel (1673) could also perform multiplication and division.

 

Jacquard’s Loom (1801).

 A French textile manufacturer Joseph Marie Jacquard, French Weaver invented a method of controlling weaving of looms to produce complex cloth patterns by using a series of first “punch-card” the machine. In the year 1801, the punch card mechanism was used in Jacquard’s Loom. The pattern woven by the loom was determined by the placement of holes in a control card. Only those threads, who are guiding hook encountered a hole in the card could enter the pattern.

 

Babbage’s Analytical Engine (1833).

 After the success of the Difference Engine, in the year 1833 Babbage’s developed a grand machine, which is known as “Analytical Engine”. This machine was fully automatic and it was consist of the following five basic units.

Input

Control

Store

Mill

Output

 

This arrangement of the five basic parts of the analytical engine is similar to the arrangement of the various units of a modern computer.

 Lady Ada Lovelace was a mathematician, who developed the binary (0, 1) numbers system, for Babbage’s machines.

 Charles Babbage is infecting considered to be the “FATHER OF COMPUTER” as he was the person, who formulated the basic principles upon which a computer is designed. Unfortunately, Charles Babbage could not complete his machine due to a lack of appropriate technology. But the laid down the principle on which modern computer works.

The Middle Age (1890 To 1944)

The duration of the middle ages of the computer is from 1890 to 1944. The work of analyzing the data related to the census of 1880 in the USA was proving very difficult for the US Bureau of the census. Dr. Herman Hollerith, a statistician with the bureau, suggested a mechanized and faster solution to the problem. Dr. Herman Hollerith developed a Punch Card Machine and tabulators to process the information on these cards. This machine used 3 by 5 inches punched card to record the data.

 

Later, Hollerith developed a machine which could perform addition and these machines were used by the railways accounting department in New York.

 In 1896, Hollerith established his own company named Tabulating Machine Company. This company was sold by Hollerith and in 1924 this became the International Business Machine Corporation (IBM). Nowadays this is the largest and world-famous computer manufacturing multinational company.

 In 1908, Dr. James Powers patented a 20-column punching machine.

 In 1930, Dr. Vanner Bush built a huge mechanical computer for solving differential equations. It was completely mechanical except for motors.

 

The Modern Age (1994 To Till)

 The modern age of the computer started from 1994 to till. Due to the rapid development of electronic computers history of modern age divided into five generations, which are below:

 

S. NO	GENERATION AND DESCRIPTION
1	First Generation The period of the first generation: 1946-1959. Vacuum tube-based.
2	Second Generation The period of the second generation: 1959-1965. Transistor-based.
3	Third Generation The period of the 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.

 

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. But nowadays, generation includes both hardware and software, which together make up an entire computer system.

 

There are totally five computer generations known to date.  Each generation has been discussed in detail along with their time period and characteristics. Here approximate dates against each generation have been mentioned which are normally accepted.

 

 

First Generation – (1946 – 1959)

 The period of the first generation was 1946-1959.  The computers of first-generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit). These tubes, like electric bulbs, produced a lot of heat and were prone to the frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organizations.  In this generation mainly batch processing operating systems were used.

Punched cards, paper tape, and magnetic tape were used as input and output devices.  The computers in this generation used machine code as a programming language.

 The main features of the first generation are:

·         Vacuum tube technology

·         Unreliable

·         Supported machine language only

·         Very costly

·         Generated a lot of heat

·         Slow input and output devices

·         Huge size

·         Need of A.C.

·         Non-portable

·         Consumed a lot of electricity

Some computers of this generation were:

·         ENIAC

·         EDVAC

·         UNIVAC

·         IBM-701

·         IBM-650

Second Generation – (1959 – 1965)

 The period of the second generation was 1959-1965.  In this generation, transistors were used that were cheaper, consumed less power, more compact in size, more reliable, and faster than the first generation machines made of vacuum tubes. In this generation, magnetic cores were used as primary memory and magnetic tape and magnetic disks as secondary storage devices. In this generation assembly language and high -level programming languages like FORTRAN, COBOL was used.  The computers used batch processing and multiprogramming operating system.

The main features of the second generation are:

·         Use of transistors

·         Reliable in comparison to first-generation computers

·         Smaller size as compared to first-generation computers

·         Generated less heat as compared to first-generation computers

·         Consumed less electricity as compared to first-generation computers

·         Faster than first-generation computers

·         Still very costly

·         A.C. needed

·         Supported machine and assembly languages

 

Some computers of this generation were:

·         IBM 1620

·         IBM 7094

·         CDC 1604

·         CDC 3600

·         UNIVAC 1108

 Third Generation – (1965 – 1971)

The period of the third generation was 1965-1971.  The computers of the third generation used integrated circuits (IC's) in place of transistors.  A single IC has many transistors, resistors, and capacitors along with the associated circuitry.

The IC was invented by Jack Kilby. This development made computers smaller in size, reliable, and efficient. In this generation, remote processing, time-sharing, multi-programming operating systems were used. High-level languages (FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL-68, etc.) were used during this generation.

 The main features of third-generation are:

·         IC used

·         More reliable in comparison to the previous two generations

·         Smaller size

·         Generated less heat

·         Faster

·         Lesser maintenance

·         Still costly

·         A.C needed

·         Consumed lesser electricity

·         Supported high-level language

 

Some computers of this generation were:

·         IBM-360 series

·         Honeywell-6000 series

·         PDP(Personal Data Processor)

·         IBM-370/168

·         TDC-316

Fourth Generation – (1971 – 1980)

The period of the fourth generation was 1971-1980.  The computers of fourth-generation used Very Large Scale Integrated (VLSI) circuits.  VLSI circuits having about 5000 transistors and other circuit elements and their associated circuits on a single chip made it possible to have microcomputers of the fourth generation. Fourth-generation computers became more powerful, compact, reliable, and affordable. As a result, it gave rise to a personal computer (PC) revolution.  In this generation time-sharing, real-time, networks, distributed operating systems were used. All the high-level languages like C, C++, and DBASE, etc. were used in this generation.

 

The main features of fourth-generation are:

·         VLSI technology used

·         Very cheap

·         Portable and reliable

·         Use of PC's

·         Very small size

·         Pipeline processing

·         No A.C. needed

·         Concept of the internet was introduced

·         Great developments in the fields of networks

·         Computers became easily available

 

Some computers of this generation were:

·         DEC 10

·         STAR 1000

·         PDP 11

·         CRAY-1(Super Computer)

·         CRAY-X-MP(Super Computer)

 

Fifth Generation – (1980 – Till)

The period of fifth-generation is the 1980-till date.  In the fifth generation, the VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components.  This generation is based on parallel processing hardware and AI (Artificial Intelligence) software. AI is an emerging branch in computer science, which interprets the means and methods of making computers think like human beings. All the high-level languages like C and C++, Java, .Net, etc. are used in this generation.

 

AI includes:

·         Robotics

·         Neural networks

·         Game Playing

·         Development of expert, systems to make decisions in real-life situations.

·         Natural language understanding and generation.

The main features of fifth-generation are:

·         ULSI technology

·         Development of true artificial intelligence

·         Development of Natural language processing

·         Advancement in Parallel Processing

·         Advancement in Superconductor technology

·         More user-friendly interfaces with multimedia features

·         Availability of very powerful and compact computers at cheaper rates

 

Some computer types of this generation are:

·         Desktop

·         Laptop

·         NoteBook

·         UltraBook

·         Chromebook