First Generation (1940-1956) Vacuum TubesThe first computers used vacuum tubes for circuitry andmagnetic drumsformemory, and were often enormous, taking up entire rooms. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.First generation computers relied onmachine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts.The UNIVAC andENIACcomputers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.

Second Generation (1956-1963) TransistorsTransistorsreplaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not see widespread use in computers until the late 1950s. The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output.Second-generation computers moved from crypticbinarymachine language to symbolic, orassembly, languages, which allowed programmers to specify instructions in words.High-level programming languageswere also being developed at this time, such as early versions ofCOBOLandFORTRAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.The first computers of this generation were developed for the atomic energy industry.

Third Generation (1964-1971) Integrated CircuitsThe development of theintegrated circuitwas the hallmark of the third generation of computers. Transistors were miniaturized and placed onsiliconchips, calledsemiconductors, which drastically increased the speed and efficiency of computers.Instead of punched cards and printouts, users interacted with third generation computers throughkeyboardsandmonitorsandinterfacedwith anoperating system, which allowed the device to run many differentapplicationsat one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.Fourth Generation (1971-Present) MicroprocessorsThemicroprocessorbrought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in 1971, located all the components of the computerfrom thecentral processing unitand memory to input/output controlson a single chip.In 1981IBMintroduced its first computer for the home user, and in 1984Appleintroduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development ofGUIs, themouseandhandhelddevices.

Fifth Generation (Present and Beyond) Artificial IntelligenceFifth generation computing devices, based onartificial intelligence, are still in development, though there are some applications, such asvoice recognition, that are being used today. The use ofparallel processingand superconductors is helping to make artificial intelligence a reality.Quantum computationand molecular andnanotechnologywill radically change the face of computers in years to come. The goal of fifth-generation computing is to develop devices that respond tonatural languageinput and are capable of learning and self-organization.

Anintegrated circuit (IC)is a small electronic device made out of a semiconductor material. The first integrated circuit was developed in the 1950s by Jack Kilby of Texas Instruments and Robert Noyce of Fairchild Semiconductor.

S.N.Generation & Description

1First GenerationThe period of first generation: 1946-1959. Vacuum tube based.

2Second GenerationThe period of second generation: 1959-1965. Transistor based.

3Third GenerationThe period of third generation: 1965-1971. Integrated Circuit based.

4Fourth GenerationThe period of fourth generation: 1971-1980. VLSI microprocessor based.

5Fifth GenerationThe period of fifth generation: 1980-onwards. ULSI microprocessor based

First GenerationThe period of first generation was 1946-1959.First generation of computers started with using 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 frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organisations.In this generation, mainly batch processing operating systems were used. In this generation, Punched cards, Paper tape, Magnetic tape Input & Output device were used.There were machine codes and electric wired board languages used.

The main features of First Generation are: Vacuum tube technology Unreliable Supported Machine language only Very costly Generate lot of heat Slow Input/Output device Huge size Need of A.C. Non-portable Consumed lot of electricitySome computers of this generation were: ENIAC EDVAC UNIVAC IBM-701 IBM-650Second GenerationThe period of second generation was 1959-1965.This generation using the transistor 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 language like FORTRAN, COBOL were used.There were Batch processing and Multiprogramming Operating system used.

The main features of Second Generation are: Use of transistors Reliable as compared to First generation computers Smaller size as compared to First generation computers Generate 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 Support machine and assembly languagesSome computers of this generation were: IBM 1620 IBM 7094 CDC 1604 CDC 3600 UNIVAC 1108Third GenerationThe period of third generation was 1965-1971.The third generation of computer is marked by the use of 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, Real-time, Multi-programming Operating System were used.High-level language (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 Smaller size Generate less heat Faster Lesser maintenance Still costly A.C. needed Consumed lesser electricity Support high-level languageSome computers of this generation were: IBM-360 series Honeywell-6000 series PDP(Personal Data Processor) IBM-370/168 TDC-316Fourth GenerationThe period of Fourth Generation was 1971-1980.The fourth generation of computers is marked by the use of 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 fourth generation. Fourth Generation computers became more powerful, compact, reliable, and affordable. As a result, it gave rise to personal computer (PC) revolution.In this generation, Time sharing, Real time, Networks, Distributed Operating System were used.All the higher level languages like C and C++, 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 internet was introduced Great developments in the fields of networks Computers became easily availableSome computers of this generation were: DEC 10 STAR 1000 PDP 11 CRAY-1 (Super Computer) CRAY-X-MP (Super Computer)Fifth GenerationThe period of Fifth Generation is 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 means and methods of making computers think like human beings.All the higher 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 ratesSome computers types of this generation are: Desktop Laptop NoteBook UltraBook ChromeBook

First Generation of Computers (1942-1955)

Image Courtesy:www.computerhistory.orgThe beginning of commercial computer age is fromUNIVAC(Universal Automatic Computer). It was developed by two scientistsMauchlyandEchertat the Census Department of United States in 1947.The first generation computers were used during 1942-1955. They were based onvacuum tubes. Examples of first generation computers areENIVACandUNIVAC-1.Advantages Vacuum tubes were the only electronic component available during those days. Vacuum tube technology made possible to make electronic digital computers. These computers could calculate data in millisecond.Disadvantages The computers were very large in size. They consumed a large amount of energy. They heated very soon due to thousands of vacuum tubes. They were not very reliable. Air conditioning was required. Constant maintenance was required. Non-portable. Costly commercial production. Limited commercial use. Very slow speed. Limited programming capabilities. Used machine language only. Used magnetic drums which provide very less data storage. Used punch cards for input. Not versatile and very faulty.Similar Topics:Types of Computers by Purpose|Types of PrintersSecond Generation Computers (1955-1964)

Image Courtesy:www.ibm.comThesecond generation computersusedtransistors. The scientists at Bell laboratories developed transistor in 1947. These scientists include John Barden, William Brattain and William Shockley. The size of the computers was decreased by replacing vacuum tubes with transistors. The examples of second generation computers areIBM 7094 series,IBM 1400 seriesandCDC 164etc.Advantages Smaller in size as compared to the first generation computers. The 2nd generation Computers were more reliable Used less energy and were not heated. Wider commercial use Better portability as compared to the first generation computers. Better speed and could calculate data in microseconds Used faster peripherals like tape drives, magnetic disks, printer etc. Used Assembly language instead of Machine language. Accuracy improved.Disadvantages Cooling system was required Constant maintenance was required Commercial production was difficult Only used for specific purposes Costly and not versatile Puch cards were used for input.Third Generation Computers (1964-1975)

Image Courtesy:www.computerhistory.orgTheThird generation computersused theintegrated circuits (IC). Jack Kilby developed the concept of integrated circuit in 1958. It was an important invention in the computer field. The first IC was invented and used in 1961. The size of an IC is about square inch. A single IC chip may contain thousands of transistors. The computer became smaller in size, faster, more reliable and less expensive. The examples of third generation computers areIBM 370,IBM System/360,UNIVAC 1108andUNIVAC AC 9000etc.Advantages Smaller in size as compared to previous generations. More reliable. Used less energy Produced less heat as compared to the previous two generations of computers. Better speed and could calculate data in nanoseconds. Used fan for heat discharge to prevent damage. Maintenance cost was low because hardware failure is reare. Totally general purpose Could be used for high-level languages. Good storage Versatile to an extent Less expensive Better accuracy Commercial production increased. Used mouse and keyboard for input.Disadvantages Air conditioning was required. Highly sophisticated technology required for the manufacturing of IC chips.Fourth Generation Computers (1975-Present)

The fourth generation computers started with the invention of Microprocessor. The Microprocessor contains thousands of ICs.Ted Hoffproduced the first microprocessor in 1971 forIntel.It was known as Intel 4004. The technology of integrated circuits improved rapidly. The LSI (Large Scale Integration) circuit and VLSI (Very Large Scale Integration) circuit was designed. It greatly reduced the size of computer. The size of modern Microprocessors is usually one square inch. It can contain millions of electronic circuits. The examples of fourth generation computers areApple Macintosh & IBM PC.Advantages More powerful and reliable than previous generations. Small in size Fast processing power with less power consumption Fan for heat discharging and thus to keep cold. No air conditioning required. Totally general purpose Commercial production Less need of repair. Cheapest among all generations All types of High level languages can be used in this type of computersDisadvantages The latest technology is required for manufacturing of Microprocessors.Fifth Generation Computers (Present & Beyond)Scientists are working hard on the5thgeneration computerswith quite a few breakthroughs. It is based on the technique ofArtificial Intelligence (AI).Computers can understand spoken words & imitate human reasoning. Can respond to its surroundings using different types of sensors. Scientists are constantly working to increase the processing power of computers. They are trying to create a computer with real IQ with the help of advanced programming and technologies.IBM Watsoncomputeris one example that outsmartsHarvard University Students.The advancement in modern technologies will revolutionize the computer in future.