Module 1

Structure of Lesson

1.1 Learning Objectives

1.2 Introduction to different generations of computers

1.3 History of Computer

1.3.1 First generation of computers

            1.3.1.1 Major characteristics

1.3.1.2 Disadvantages of first generation computers

1.3.1.3 Features of first generation computer

1.3.2 Second generation of computers

1.3.2.1 Major characteristics

1.3.2.2 Disadvantages of second generation computers

1.3.2.3 Features of second generation computer

1.3.3 Third generation of computers

1.3.3.1 Major characteristics

1.3.3.2 Disadvantages of third generation computers

1.3.3.3 Features of third generation computer

1.3.4 Forth generation of computers

1.3.4.1 Major characteristics

1.3.4.2 Disadvantages of forth generation computers

1.3.5 Fifth generation of computers

1.3.5.1 Major characteristics

1.3.5.2 Disadvantages of fifth generation computers

1.4 Summary

1.5 Glossary

1.6 Suggested Answer to SAQ

1.7 References/Bibliography

1.8 Suggested readings

1.9 Review Questions

1.1 Learning Objectives

 After learning this chapter, you will know about

• Generations of computers
• Technological advancements leading to modern day computers
• Overview about different landmarks achieved in generations of computer

1.2 Introduction to different generations of computers

 “Generation” in terms of computers means a change or transformation in technology leading to an improved version of the system. The different generations of computers differ from each other in having different sizes and features. Earlier, the term generation included the different stages based on the hardware only. But, in recent times, generations include both software and hardware. Till date, a total of five generations of computers have been developed. Before, we understand the various generations of computers; let us quickly recall the definition of computer. A computer is defined as an electronic machine that is capable of receiving data, processing the data and giving result in the form of output. Actually, computer is derived from the latin word “compute”, basically the meaning of the word “computer” is “to count or to calculate”.  So, the computer was initially meant to perform mathematical operations that eased human work. From a humble beginning, the fifth generation computer has come a long way.

1.3 History of Computers

The history of computers dates back to 2500 B.C. when man decided to use machines to help in calculations and thus ABACUS or a counting frame was invented. Subsequently, a number of inventions and innovations led the way to the development of the first generation of computers in 1930’s.  Over the 60 years or so, computer industry has witnessed the development of five generations of computers.

OLD STYLE COMPUTER

1.3.1 First generation of computers

 Date-wise speaking, any computer before 1950 is called first generation computer. The first generation of computers (1936-1950) used electronic valves i.e. vacuum tubes (fragile glass devices which amplify signals). It is an archetype computer, which had no operating system of its own.

Examples of first generation computers

The first of its kind was ENIAC (Electronic numeric integrator and computer). In fact, ENIAC contained almost 17,000 vacuum tubes, 7200 crystal diodes, 1500 relays, 70,000 resistors, 10,000 capacitors and approximately 5 million hand-welded joints. This computer was huge and occupied around 1800 square feet. It also consumed enormous amount of power. The input used to be from IBM card reader and the output was from IBM cardpunch. It was developed at the Moore School of Electrical Engineering, University of Pennsylvania, and Philadelphia. The ENIAC was sent to Aberdeen, Maryland where it was used for military purposes especially in ballistics along with other scientific uses. Another major example of first generation computer was EDSAC (Electronic Delay Storage Automatic Calculator). EDSAC was a British computer, which used vacuum tubes and mercury delay lines. Punched taped served as the source of input whereas teleprinter gave the output. It also used the concept of subroutines for the first time. It was chiefly built to study computer programming. Certain researchers feel that the concept of first generation computers actually started with the UNIVAC I (Universal Automatic computer), which was built in 1951. It was sold to US Census Bureau. It was designed by Eckert-Mauchly  computer Corporation and dedicated to business purposes. Other major examples included IBM650 and EDVAC (Electronic discrete variable automatic computer).

1.3.1.1 Major characteristics of first generation computer

Hardware: Vacuum tubes were the source of circuitry as they were the only electronic components available at the time.  However, the vacuum tubes were very big in size. The magnetic drums served the purpose of supplying primary internal-storage medium. The input was through punched cards which was a slow method of input. The output came through paper tapes.

Software: These computers used machine language, which was cumbrous and used 0’s and 1’s. In 1952, mnemonics (instructions written in symbolic codes) developed by Dr. Grace Hooper were translated into binary code for the computer.

Uses: They were mainly used in military, scientific investigations, record keeping and other business purposes.

Computing Time: The computing time used by these computers was in the order of milliseconds and they could take up only one problem at a time. Nevertheless, they were the fastest devices of the time.

Outward form: They were very bulky, heavy, big and occupied a lot of space. They usually needed a large room.

1.3.1.2 Disadvantages of first generation computers

Heating: There were a number of vacuum tubes involved and they consumed a lot of heat and power. The vacuum tubes heated up very fast and often burnt easily. For their maintenance, special air-conditioning was required.

Prone to crashing: These computers were prone to repeated hardware disasters and needed constant maintenance.

Bulky and non-portable: The machines were huge and had to be stored in a large place and could not be moved. In fact, they took up the entire floor of buildings.

Expensive: These computers were very costly and needed a lot of initial expenditure in manufacturing. Further, they had a limited commercial use. Only some privileged institutions had access to them.

1.3.1.3 Features of first generation computers at a glance

·         Vacuum tube technology

·         Unpredictable

·         Supported Machine language only

·         Very costly

·         Generated lot of heat

·         Slow Input/Output device

·         Giant size

·         A.C Required

·         Non moveable

·         Consumed lot of electricity

1.3.2 Second generation of computers (1955-1964)

The second generation of computers used transistors (a semiconductor device which regulates the flow of electric signals and acts a switch or gate for electric signals) as the brain of computer in place of vacuum tubes. These computers which used transistors coupled with magnetic core memory were much faster, reliable and also much smaller than their forerunners.

Examples of second generation computers

Major examples of these kinds of computers were IBM 1401, IBM 7000, NCR 304, ATLAS etc. They were transistorized and were more energy efficient. An important example i.e. IBM1401 was unanimously acknowledged throughout the industry and is considered to be the model T of the computer industry. Second generation computers had the ability of stored program (i.e. instructions to run a computer for a specific time) and programming language, which made it profitable and helpful for business use. These computers had faster input/output devices which made these quite efficient.

1.3.2.1 Major characteristics of second generation computer

Hardware: Tiny solid-state transistors replaced vacuum tubes as the source of circuitry making these computers much smaller and reliable.  This also reduced the heat problem of the computers. Magnetic core (electric current passing through wires magnetize an internal core) served the purpose of primary storage whereas magnetic tapes and disks (looking like phonograph records) were used as secondary storage devices. Input was through punched cards and output was through printouts but printing was faster and correction of errors was feasible. However, physical assemblage of several thousands of individual parts into a sole serviceable unit was still necessary.

Software: Assembly languages were used to write the instructions to the computer. They used mnemonics like ADD for addition and SUB for subtraction. High level languages like COBOL (Common Business Oriented Language), FORTRAN (Formula Translator) were also used. Its main features included: file processing, editing, input/output capabilities.

Uses: These types of computers were quite useful in schools, institutions, business houses as well as for the hobbyists. They also found use in atomic energy industry. They also allowed the scientists to fly in space. They had their own operating system that made them more appreciable. Nevertheless, the manual assembly of the computer made it difficult to produce commercially and also very costly.

Computing time: Computing time decreased substantially with the advent of second generation computers. The computing was in the order of microseconds.

Outward form: Smaller than the first generation computers and were quite portable also since the transistors were much smaller than the vacuum tubes.

1.3.2.2 Disadvantages of second generation computers

Heating: These computers also heated up even if the heat problem was much lesser as compared to their predecessors. For their maintenance, special air-conditioning was required.

Frequent maintenance required: These computers also showed frequent malfunctioning but the entire sections called “breadboards” (temporary circuit boards) could be replaced in case the machine “crashed”.

Expensive: The manufacturing cost of these computers was quite high.

1.3.2.3 Features of second generation computers at a glance

·         Transistor technology

·         Supported High level languages like COBOL and FORTRAN

·         Smaller in size

·         More reliable

·         Generated less heat

·         Faster Input/Output devices

·         A.C Required

·         Improved portability

1.3.3 Third generation of computers (1959-1971)

The third generation of computers used microelectronics technology. They contained integrated circuits (a set of electronic circuits on a plate of semi conductor material like silicon) as the circuitry. These computers which used integrated circuits or chips almost revolutionized the computer system. The ICs used very small (5 square millimeter) surface of silicon (chip) and thus they were far smaller than their predecessors.

Examples of third generation computers

 Chief examples of these kinds of computers were IBM system 360, NCR 395, Burroughs B 6500 etc. Other examples include Apple computers, CDC’s (Control Data Corporation), Cyber-175. These computers were significantly superior to the previous generation in terms of speed and efficiency. These were also equipped with keyboards and monitors and also had an operating system interface. Many different applications could be run simultaneously on these computers. In a nutshell, these were more powerful and much smaller than the previous computers.

1.3.3.1 Major characteristics of third generation computer

Hardware: Integrated circuits substituted for the transistors in third generation. The invention of IC’s allowed scores of electronic components to be put on silicon circuit chips on an area about one fifth of a centimeter and the fraction of the cost. Initially magnetic disks were used as memory devices that were later replaced by semiconductors. External storage in form of floppy disks was also in trend. The Input through punched cards was no longer required because users could interact with the computer through keyboards and monitors. Furthermore, manual assemblage of was not necessary anymore. The improved hardware permitted mass audience and multiprogramming was also initiated.

Software: It was during this time that the software industry developed. Many important programming languages were written during these times like ADA, PASCAL, BCPL, SQL etc. These were quite cost-effective as programs need not be rewritten and many users bought pre-programmed packages. The operating systems of these computers enabled the I/O and perform the tasks handled by humans.

Uses: The multitasking and timesharing (many users could use a single machine at the same time) benefit of these computers made them very successful and versatile. The same machine could be used to run business, scientific as well as other operations. These types of computers were quite useful in record keeping, inventory making, scheduling, forecasting, billing, payrolls, credit cards usage etc. these computers were also much cheaper. These computers could be used by remote terminals also.

Computing time: Computing time decreased considerably from microseconds to nanoseconds.

Outward form: Progress in solid state expertise helped in designing much smaller and quicker computers. The computers were very handy and portable now.

1.3.3.2 Disadvantages of third generation computers

Manufacturing IC’s required highly complicated technology: Although IC’s minimized the size and increased the efficiency of the computers, yet they were not easy to build. Building silicon chips or IC’s required a lot of sophistication and technical expertise.

Still required AC’s: Despite their low maintenance and minimized hardware failure rate, they still needed AC’s for temperature regulation.

1.3.3.3 Features of third generation computers at a glance

·         IC technology

·         Smaller in size

·         More reliable

·         Generated even  lesser heat

·         Faster Input/Output devices

·         A.C Required

·         Commercial production less expensive

·         Required less power

·         Very easy to carry

·         Manual assembly not required, so reduced time and human labor

·         Lesser computation time

1.3.4 Fourth Generation (1975 onwards) – Microprocessor

These computers were the expansion of the third generation technology and emerged with the development of VLSI (Very large scale integration). The advances in VLSI gave birth to the technique of microprocessors (a small chip equivalent to the size of a postage stamp containing thousands of integrated circuits). Microprocessors could hold the entire computer control unit on a small chip. Now, the computers which in their early stages occupied an entire floor of the building could be fitted on a desk or a lap.

Examples of fourth generation computers

Major examples of these kinds of computers are IBM 4341, DEC 10, STAR1000, PUP11, Apple II, INTEL series etc. Out of these, IBM launched for the first time, a computer for home users. Apple also started using Macintosh microprocessor. These types of computers brought about a PC revolution. INTEL 8008, a very versatile and potent microprocessor was introduced in 1971; it was also the first microprocessor to be used in personal computers. Floppy disk was also introduced in 1971 whereas hard disk was introduced seven years later, i.e. in 1978. First optical disk and first portable computer (Osborne) were also of this generation. They were introduced in 1980 and 1981 respectively. Cray-1, CP/M are also examples of fourth generation computers. These were also amongst the cheapest computers of all the generations. Smaller computers could be linked together using LAN (local area network) or telephone wires. These kinds of computers also saw the emergence of “Internet.”

1.3.4.1 Major characteristics of fourth generation computer

Hardware: The brain of computers in this case is a microprocessor i.e. a chip having cores of transistors and other components put together with the help of LSI and VLSI technology. The memory part uses semiconductors instead of earlier used magnetic devices. This helped in increasing the efficiency of access to the memory. Further, the secondary storage devices became tinier and more efficient. A crucial advancement of this area is the inter-linking of computers, which led the way to Internet revolution. Hardware technology of fourth generation computers also saw the rise of certain pointing devices like mouse and other hand-held pointers.

Software: Many high level languages could be used like C, C++, DBASE etc. A unique feature is the support of GUI (Graphical User Interface). Numerous novel operating systems like MS-DOS and MS-Windows also became in practice during this time.

Uses: Fourth generation computers were quite useful as they are powerful, reliable, very compact in size and also reasonable in cost. As the computers start becoming more and more widespread, new ways to harness their seemingly limitless potential were discovered.  Starting from banks, hospitals, media, entertainment, research, space technology, booking counters at railways, airports, educational institutions, social networking and in fact most of the nooks and corners of modern day life

Computing time: Computing time decreased further and became of the order of picoseconds now.

Outward form: The computers of the fourth generation are so small that they are also known as microcomputers. They can fit onto a desk, in our laps and also in the palm of our hands.

The main features of Fourth Generation are:

·         VLSI technology used

·         Very economical

·         Handy 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 available

1.3.4.2 Disadvantages of fourth generation computers

Very sophisticated: Hugely advanced techniques are needed to fabricate LSI and VLSI.

1.3.5 FIFTH GENERATION Computers

(1981-onwards) The fifth generation computers can be defined as ultra large integrated circuit (ULIC) computers with millions of electronic circuits, also armed with multiple processors so that each processors gets to perform fewer tasks. This increases their efficiency many-fold. They are also equipped with artificial intelligence, capable of taking independent judgments and are extremely small in size.

Examples of fifth generation computers

These computers cover the present and future. Some of the examples include LASERS, Holographic computers. These computers include the latest technologies like mega chips, parallel processing, and artificial intelligence. The first fifth generation computer project was initiated in Japan in 1982. New technologies like X-Rays, lasers, electron chips are being initiated to fabricate advanced level microprocessors to suit the needs of artificial intelligence. In fact, this generation is a climb past all other machines.

1.3.5.1 Major characteristics of fifth generation computer

Hardware: The fifth generation computers use/will use large scale integration and very large scale integration technology as the source of circuitry (mega chips). The primary memory is/will be EEPROM (Eclectically erasable programmable read only memory), SIMM (Single in line memory module) and DIMM (Dual in line memory module). The concept of bubble memory is also introduced in this generation. Fifth generation computers are equipped with multi-processors so that a huge number of tasks can be performed at a given point of time via parallel processing. External storage is/will be in form of improved optical as well as magnetic disks.  The input devices include scanner, keyboard, pointers and output device is the monitor.

Software: Operating Systems are GUI based. Since these computers have artificial intelligence, they use/will use expert systems (ES), natural language processing (NLP), robotics, speech and vision recognition also. These computers shall make use of higher level languages like C, C++, Java, .Net etc. These computers possess the power of speech recognition, pattern identification, logical thinking like humans. These computers shall use the radical techniques of quantum computation and molecular nanotechnology.

Uses: The major aim of fifth generation computers is to make such devices which will respond to human language and also possess the genuine understanding of the world. These computers won’t just process the numeric data but also the real world information. In short, they are aimed to have the power like that of human intelligence, logical reasoning, decision making, image and graphical recognition. Apart from performing all the regular tasks at various places like educational institutes, hospitals, booking offices, space research, remote sensing, underground research, mining, media and entertainment, these computers shall also find role in gaming, robotics, neural networks, simulate real life situations, decision making etc.  So, we may have final machines which can interact with human beings.

Computing time: Computing time reduced further and is in the order of nanoseconds now.

Outward form: Extremely small size e.g. pocket P.C.., chrome book, notebook, tablets, laptops, palm tops, digital diaries.

The main features of Fifth Generation are:

·         Very large storage

·         Mega chips using advanced circuitry with ULSI technology

·         Artificial intelligence

·         NLP (Natural language processing)

·         The advantage of parallel processing

·         Human friendly interface

·         Powerful and compact computers at affordable price

1.3.5.2 Disadvantages of fifth generation computers

Excess of technology: In trying to make humans out of machines, we are making machines out of humans. This has socially and emotionally jeopardized the human behavior. Further,  the ill effects on health with too much use of computers are too many to be overlooked.

Highly advanced: The software and hardware are highly sophisticated and some of them are still in the stage of development.

Growth of computer system with technological advancement: a quick glance shown in table 1.1

                                                Table 1.1

1.4 Summary

Computers have completely changed the life-style of modern humans. Today computers have become almost a necessity in modern house-hold. Life is actually not conceivable without the computers for many of the modern humans. However, it has taken a journey of many decades for the technology to evolve and reach the present state. The various landmarks in the technological advancements of the computers leading to a better and improved version or model of computer i.e. machines having basic leaps in technology are roughly referred to as different generations of computers. The history of computers dates back to almost 2300 B.C. when the Chinese invented the first device to help in calculations i.e. the abacus. But, the word computer appeared for the first time in seventeenth century and it was used to describe a person who performed calculations. In nineteenth century, the word computer was used for the first time for a machine which would perform calculations. Starting from 1940s till date, the various technological milestones achieved by computers are divided into five generations of computers i.e. first, second, third, fourth and fifth. With each successive generation, the circuitry of the computer started becoming more complex, the size became progressively smaller, computers became more versatile and their power, speed and memory has become much larger.

First Generation Computers

These came into existence in mid 1940s. They relied heavily on vacuum tubes for circuitry and magnetic drums for memory. They were actually so big in size that they would occupy a very large room. These computers were so large because a vacuum tube was very big and a number of vacuum tubes were put together to make a computer. Further, these computers performed only one function at a time. The input was a cumbersome and slow process in which punched cards were used and output was received on punched tapes. The memory was stored in magnetic drums and machine language was used. These computers used the time in the order of milliseconds for performing the computing operations. These huge computers were very costly and only privileged institutions could afford to possess them. ENIAC, EDSAC, UNIVAC are he examples of first generation of computers.

Second Generation Computers

They came into being in about mid-1950s. They were a step ahead than their predecessors in having transistors as their circuitry. Transistors were much smaller than vacuum tubes and were lesser prone to burning. So, the computer system reduced in size and also faced lesser crashes or hardware failure. These computers were much more useful in atomic research. Their memory was stored in magnetic core rather than a magnetic drum. Further, these computers progressed from using binary language to COBOL, FORTRAN and other languages. Nevertheless, these were still very expensive and heated up very fast. IBM 1401, IBM 7000, NCR 304, ATLAS were some of the second generation computers. Computing time decreased substantially with the advent of second generation computers. Now, the computing time was of the order of microseconds.

Third Generation of computers

The third generation computers are characterized by the presence of integrated circuits (IC’s) as the brain of the computer. IC’s used very small surface of silicon chip thus helping in reducing the size of the computer.  The heat generated by the transistors and vacuum tubes was too high and damaged the internal system of computers. The integrated circuits reduced the heat loss considerably and also decreased the power consumption of the computers. Now the computers were for the first time accessible to masses as their prices also dropped down. IBM system 360, NCR 395, Burroughs B 6500, Apple computers, CDC’s (Control Data Corporation), Cyber-175 are a few examples of these types of computers. The memory was now stored in semiconductors instead of magnetic cores and mode of input also change from punched cards to keyboards. The output could be received on monitors. SO, third generation computers are considered to be again leap in technology.

Fourth Generation Computers

These computers came into existence in 1975 and they are considered to be the harbingers of microelectronics. They were the expansions of third generation and instead of just IC’s; they had VLSI (very large scale Integration) as their circuitry. They had microprocessors as their brain. Thousands of integrated circuits were put together on a single chip to give rise to what is called as “microprocessor”. With the advent of microprocessors, the computers became so small that they could now be fit into a hand as compared to the original computers which needed a whole room for installation. APPLE also introduced Macintosh microprocessor.  This generation of computers was also fit for home use.  A crucial advancement of this area is the inter-linking of computers, which led the way to Internet revolution. Hardware technology of fourth generation computers also saw the rise of certain pointing devices like mouse and other hand-held pointers. Many high level languages could be used like C, C++, DBASE etc. A unique feature is the support of GUI (Graphical User Interface). Fourth generation computers were quite useful as they are powerful, reliable, very compact in size and also reasonable in cost.

Fifth Generation of computers

(1981-onwards) The fifth generation computers can be defined as ultra large integrated circuit (ULIC) computers with millions of electronic circuits, also armed with multiple processors so that each processors gets to perform fewer tasks. Many fifth generation computing devices are still in developmental stages. Actually, these computers are dreamt to be the human simulators with artificial intelligence and expert systems. They are aimed at having the capability of voice and vision recognition and a human interface. The fifth generation computers use/will use large scale integration and very large scale integration technology as the source of circuitry (mega chips). The primary memory is/will be EEPROM (Eclectically erasable programmable read only memory), SIMM (Single in line memory module) and DIMM (Dual in line memory module). The concept of bubble memory is also introduced in this generation. Fifth generation computers are equipped with multi-processors so that a huge number of tasks can be performed at a given point of time via parallel processing. External storage is/will be in form of improved optical as well as magnetic disks.  The input devices include scanner, keyboard, pointers and output device is the monitor. These computers are expected to change the human behavior as they have entered every nook and corner of our lives. So the technology developers need to beware so that in trying to make humans out of machines, they may not make machines out of humans.

1.5 Glossary

Vacuum Tubes	Fragile glass devices which amplify signals
Punched Cards	Cards containing punched holed to represent data
Punched Tape	Perforated paper tapes used to store data
Machine Language	A binary language in form of 0s and 1s that is directly understood by the computer.
Assembly Language	A low level programming language most specific to a concerned machine’s architecture and needs a utility program for the machine to execute the assembly language.
Transistor	A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power.
ENIAC	Electronic Numerical Integrator and Computer
COBOL	Common Business Oriented Language used for business programming.
FORTRAN	Formula Translation language used for Scientific programming.
Integrated Circuits	Set of a number of electronic circuits on a single plate called “chip”.
GUI	Graphical User Interface
Artificial Intelligence	A branch of computer science dealing with making computers as human simulators.

1.6 Suggested Answer to SAQ

Question What are the main features of first generation of computers?

·         Vacuum tube technology

·         Unpredictable

·         Supported Machine language only

·         Very costly

·         Generate lot of heat

·         Slow Input/Output device

·         Giant size

·         A.C Required

·         Non moveable

·         Consumed lot of electricity

Question State the name of computer belongs to first generation?

·         ENIAC

·         EDVAC

·         UNIVAC

·         IBM-701

·         IBM-650

Question Which programming language introduced during second generation computer?

FORTRAN ( Formula Translation) and COBOL (Common Business Oriented Language).

Question Explain the types of fifth generation computer?

Some computer types of this generation are:

·         Desktop

·         Laptop

·         Notebook

·         Ultra Book

·         Chrome Book

 Question What type of hardware is present in fifth generation of computers?

The brain of computers in this case is a microprocessor i.e. a chip having crores of transistors and other components put together with the help of LSI and VLSI technology. The memory part uses semiconductors instead of earlier used magnetic devices. This helped in increasing the efficiency of access to the memory. Further, the secondary storage devices became tinier and more efficient. A crucial advancement of this area is the inter-linking of computers, which led the way to Internet revolution. Hardware technology of fourth generation computers also saw the rise of certain pointing devices like mouse and other hand-held pointers.

1.7 References/Bibliography

·         “Computer Fundamental and Information Technology” by Ramesh Bangia Published by FireWall Media.

·         “A Complete Guide to Computer Fundamental” by Sudipto Das Published by University Science Press.

·         “Discovering Computer Fundamental” by Grag Shelly and Misty Veermat Published byShelly Cashman series.

·          “Computer Fundamental and Information Technology” by Ramesh Bangia Published by FireWall Media

1.8 References and Suggested Reading

·         “Computer Fundamental and Information Technology” by Ramesh Bangia Published by FireWall Media.

·         “A Complete Guide to Computer Fundamental” by Sudipto Das Published by University Science Press.

·         “Discovering Computer Fundamental” by Grag Shelly and Misty Veermat Published byShelly Cashman series.

·          “Computer Fundamental and Information Technology” by Ramesh Bangia Published by FireWall Media

·         “A Complete Guide to Computer Fundamental” by Sudipto Das Published by University Science Press.

·         “Discovering Computer Fundamental” by Grag Shelly and Misty Veermat Published by Shelly Cashman series.

·         http://www.tutorialspoint.com/computer_fundamentals/computer_generations.html

1.9 Review Questions

·         What are the Advantages and disadvantages of Vacuum Tube?

·         What are the advantages of IC?

·         Explain the Fifth generation of computer?

·         Explain the evolution of computer?

·         What do you understand by programming languages? Name any two programming languages?

Structure of Lesson

2.1 Objective of Lesson

2.2 Introduction

2.3 Classification based on principles

            2.3.1 Analog computer

            2.3.2 Digital Computer

            2.3.4 Hybrid computer

2.4 Classification based on Size and processing power

            2.4.1 Mainframe

            2.4.2 Minicomputer

            2.4.3 Microcomputer

                        2.4.3.1   Stationary

                        A)  Workstation         B) Desktop      C) Tablet         D) Home Theater PC

                        2.4.3.2 Portable

                        A) Laptop       B) Net book    C) Tablet         D) Smartphones         E) Pocket PC

            2.4.4 Supercomputer

2.5 Summary

2.6 Glossary

2.7 Suggested Answer to SAQ

2.8 References/Bibliography

2.9 Suggested Question

2.10 Review Questions

2.1 Objective of Lesson

A computer is one of the most brilliant inventions of mankind. Because of Computer technology, we have been able to achieve storage and handling of large amount of data. We can rest our brains by assigning this job to computer memory for information storage. Due to computers, we have been able to achieve higher processing speeds and accuracy. Computer of the earlier times were of the size of a large room and consumes huge amount of electric power. However, with the advancing technology, computers have shrunk to size of a small watch. Depending on their processing powers, size and area of use, they have been classified into various types. Based on the operational principle, computers can be classified as analog and digital. Based on their processing power and size, they can be categorized as mainframe, microcomputer and supercomputer. So Objective of this lesson is to understand the various types of computer on the basis of above defined criteria.

2.2 Introduction

Computer can be classified on the bases of following criteria by -

·         Operation principle of computer

·         Size and power of computer

2.3 Classification based on Principles of Operation

Depending upon the principles of operation, computers are classified into three types -

·         Analog computers

·         Digital computers

·         Hybrid computers

2.3.1 Analog Computers

An analog computer represents data as physical quantities and operates on the data by manipulating the quantities. Analog computers were well known in the 1940s although they are now uncommon. The computers which provide us continuous information are called analog computers. Analog computers represent physical quantities in the form of waves or in continuous form. Thermometer is the example of analog computers because it measures the length of a mercury column continuously. A traditional clock is the example of analog computers because the needle of clock covers the distance of dial continuously. Weighing machine and Speedometer are other examples of analog computers.

Characteristics of the analog computers:

·         Analog computers are fast in speed

·         Non dependable computers

·         Analog computer became  pedestals for launch  of digital computers

·         Complex to use

·         Easy to develop

·         Does have small even no memory

ANALOG COMPUTER

2.3.2 Digital Computers

The digital computer is designed using digital circuits in which there are two levels for input and output signals. These two levels are known as logic 0 and logic 1. Digital Computers can give the results with more accuracy and at a faster rate. Since many complex problems in engineering and technology are solved by digital computer, so digital computers have an increasing use in the field of design, research and scientific data processing. Both general purpose and special purpose digital computers are in existence. Special purpose computer is one that is built for a specific application such as calculator, digital clock, digital speedometer etc. General-purpose computers are used for any type of applications. It can store different programs and perform  the jobs as per the instructions specified in those programs ( i.e. software). Most of the computers that we see now days fall in this category. The following picture is of a general purpose digital computer.

COMPUTER

Most computers of the modern times are digital in nature. They represent information disjointedly and use a binary (two-step) system that represents each portion of information as a series of zeroes and ones. Digital computers manipulate most data more easily than analog computers. They are designed to process data in numerical form . Digital information can be copied exactly but it is difficult to make exact copies of analog information. On the other hand a digital computer operates on digital data such as numbers. It uses binary number system in which there are only two digits 0 and 1. Each one is called a bit.

2.3.3 Hybrid Computers

 The computers which have characters of both digital and analog computers are called hybrid computers. Hybrid computers have the speed of analog and the accuracy of digital computer. Desirable features of analog and digital machines can be combined to create a Hybrid Computer. This type of computer operates by counting as well as by measuring. The working of analog computer is to evaluate the physical quantities where as digital computers perform the processing on evaluated data by analog computer to produce results. In other words, the output can be either in the form of numbers or required units of measurement, e.g., an analog device measures patient’s heart beat e.g. Electrocardiogram (ECG). These measures will be converted into digital form and a digital device checks for any abnormality. Another example is a Modem. (Which converts the digital signals into analog, carry it along the line and at the receiving end again changes it back in to digital signal).

HYBRID COMPUTER

2.4 Classification of computers based on size

We’ve already seen how large the computers were and these days we are using very small computers, some even embedded in wrist watch. So, another interesting aspect to classify computers is based on size, capacity and dependability. If we look at the computers from this point of view, we can group them into four major classes -

·         Mainframe Computers

·         Minicomputers

·         Microcomputers

·         Super computer

2.4.1 Mainframe computers

In 1944 IBM developed its first mainframe computer, acknowledged as the Automatic Sequence Controlled Calculator (ASCC). This computer was the fastest computer of its times and could solve addition and multiplication problems in less than six seconds. During the late 1940’s and early 1950’s, Dr. J. Presper and Dr. John W. Mauchly  developed the Universal Automatic Computer, UNIVAC.

Characteriscits of mainframe computers

·         They are big and sensitive computer systems. They are  sensitive to temperature, humidity, dust etc.

·         Well Qualified & skilled operators are required to operate them.

·         Large number of additional devices have to be/can be attached

·         They have large storage capacity.

·         Wide verities of software can be used in these computers

·         Complex  to operate

·         More mathematical calculations are used in these types of computers.

·         They are used in large commercial places or government organizations.

Usage of mainframe in business industry:

·         Due to its fast speed it perform large-scale transaction processing (thousands of transactions per second)

·         Mainframe support multiprocessing i.e. thousands of users and application programs concurrently accessing numerous resources

·         Mainframes manage terabytes of information in databases very easily

·         It handle large-bandwidth communication in network.

2.4.2 Mini computers

 The term "minicomputer" evolved in the 1960s to describe the smaller computers that became possible with the use of transistor and core memory technologies and less expensive peripherals (I/O devices etc). They usually took up very less space as compared with the large mainframes. In 1964, by using discrete transistors a highly successful minicomputer was  developed by Digital Equipment Corporation's (DEC) named as  12-bit PDP-8. Later versions of the PDP-8 took advantage of small-scale integrated circuit

Minicomputers were also known as midrange computers. They grew to have relatively high processing power and capacity. They were used in manufacturing process control, telephone switching and to control laboratory equipment. In the 1970s, they served as the hardware that was used to launch the computer-aided design (CAD) industry.

Characteristics of Mini computers

·         Minicomputer possesses lesser memory & storage capacity as compared to the mainframe computers.

·         A very limited range of additional devices (Peripherals) can be attached with them.

·         They can use limited range of software.

·         The end users can directly operate them.

·         They are not very sensitive to the external environment.

·         They are used for data processing.

2.4.3 Micro Computers or Personal Computers

Microcomputers became popular in the 1970s and 80s with the invention  of microprocessors. The ancestor to these computers (i.e. mainframes and minicomputers), were comparatively much larger and more expensive. In fact, nowadays personal computers or Microcomputers are the most widely used computers, which have found application in everyday activity of the modern world. The speed and accuracy of processing of the personal computer accounts for its high popularity. Think of a world where share market trading had to be carried out manually and the times when the fastest means of communication were, but for the telephones, the telegrams. Those days are not even past 50 years, yet you cannot imagine life without the aid of personal computers or “PCs”. A microcomputer is a small and inexpensive computer. It includes a microprocessor, memory, and input/output facilities. Microcomputers are designed to serve only one user at a time, although they can often be modified with software or hardware to concurrently serve more than one user. Microcomputers fit well on or under desks or tables, so that they are within easy access of users. Bigger computers like minicomputers, mainframes, and supercomputers take up large cabinets or even dedicated rooms.

Types of Personal computers or Micro Computers

2.4.3.1             Stationary

A)      Workstation         B)  Desktop            C)  Net top D)  Home theater PC

2.4.3.2             Portable

         A)  Laptop  B) Net book         C) Tablet   D) Smartphone      E) Personal Digital Assistant

2.4.3.1 Stationary

Stationary refers to those types of computers, which is not portable, that is hardware or computer cannot be moved easily from one place to another. Some important types of stationary computers are -

A)  Workstation

A workstation is a computer planned for individual use that is faster and more capable than a personal computer. It is assembled for business or professional use (rather than home or frivolous use). Small engineering companies, architects, graphic designers and many  other organizations and departments use workstations. Workstations usually are built with an optimized design for complex data manipulation such as database server, network server,  image rendering and editing, computer-aided design (CAD), animations and mathematical plots.

WORKSTATIONS

B)   Desktop

We are very familiar about desktop computer. They are commonly available at all places like school, offices or at home. We often call desktop computer as a personal computer. It consists of several separate pieces of equipment which are all connected to each other with cables: CPU (Central Processing Unit), monitor, keyboard and mouse. Most modern desktops have a flat screen monitor and a tower CPU which you can stand either on the desk or on the floor. We can also use a wireless keyboard and a wireless mouse with Personal computer as input device. Now these days touch screen monitors are also in market as monitors of desktop computer. These computers are assembled and can be upgraded and if any component gets damage, we can replace it without buying a whole new computer. Additional devices such as speakers, headphone, webcam etc can be attached with desktop computers. These are stationary type computer and stay at one place and will plug to a power outlet. The most common hardware used to assemble a desktop computer includes a cabinet with power supply fixed in it, along with other equipment like motherboard, RAM, Hard Disk , Optical Disk Drive, Keyboard, Monitor and Floppy Drive if needed. Now days in market, All-in-one desktop computers are available, that is all the PC components like motherboard, hard disk, RAM is integrated in the monitor.

DESKTOP

C)   Nettop

 Very small sized desktop computers were introduced by Intel in February 2008 with a new category name  called NETTOP. It possesses all the characteristics same as desktop computers but much lower in cost and compact in size. This class of computers contains new Intel Atom processor which is specially designed by Intel consumes to less power and is much smaller in size.  A nettop (or miniature PC, Mini PC or Smart Micro PC) is very small in size, inexpensive, less power consumer than desktop computers. These computers were designed for the purpose of performing basic tasks such as Internet surfing, accessing web-based applications, document processing, and audio/video playback.   As already discussed  these computer consumed less power so they generate less heat  and consequently less cooling or no cooling is required for these computers so they may even be fan less (Normally in desktop computers a fan is fitted on the microprocessor to cool the processor). Due to their compact size they  do not have an optical disk drive,  making them completely silent. The tradeoff is that the hardware specifications and processing power are usually reduced, so due to these reason these computers are not appropriate for fast and intense processing.

NETTOP

D)  Home Theatre PC

The "Home Theater PC" term first appeared in mainstream press in 1996. Today, we find many DTH(Direct to Home) in market which provide the services like recording of data. Also, in market many LCD TV’s or Smart LCD’s are available which can run videos or display photos on your screen by using Pen drive. They all are categorized as home theater PC (HTPC) devices. Basically, these devices combine the function of personal computer, Display unit and digital video recorder. We often call them as a media server.The basic purpose of HTPC is to combine all the component of a home theatre like video player, Satellite TV  signal receiver, image displayer etc.  Since 2007, Signal digitization has promoted this technology.  Digitization of channels came into existence after this process of digitization. This increased the usage and availabilty of these devices.

2.4.3.2 Portable

A)  Laptop

 A laptop computer is a small personal computer designed for portability. The laptop is a portable type of desktop computer which is bulit in a single unit i.e. all the components like keyboard, trackpad (replacement of mouse), monitor, CPU ( hard disk , RAM, Optical drive), graphics card, speakers, mike  are bulit in a single unit. They also have batteries that provide the power to the device for a given period of time to enchance the portability of device. Battery has to be charged by plugging power. It can be recharge again and again with its life. With the advancement of technology, the weight of laptop has reduced and processing power of laptop has increased. Now, these days, some companies are concentrating their technology to increase the power backup of the battries.  To interface other hardware with the laptop, USB ports are available. This is Universal Serial Bus port to which any hardware can be attached.  Before the invention of USB, every hardware had its own port. If we want to attach that particular hardware to PC then the PC should have that hardware supported port otherwise we were not able to attach that harware to that PC (e.g Keyboard had its own port, mouse had its own port). But thanks to USB, there is a standrand port that is USB for every hardware.

LAPTOP

One main drawback of the laptop is that it is not upgradeable. Due to its small size and complex configuration, internal upgrading of laptop is difficult or impossible. If these types of computers are handled with poor care or knowledge, they may get damaged. Internal upgrading is possible upto some extent like upgradtion of RAM, Hardisk. But upgradtion of keyboard, trackpad is impossible.

B) Notebook

Notebooks are types of computers smaller than laptops in size and processing power and do not include optical drive (CD/DVD Drive). Even some notebooks do not have hard disk to store data. They are designed to consume less power, to process faster, lighter in weight  and shock resistant. Now, these days, some notebook are available in market  with different range of storage capacity  i.e. from 32 GB to 2 TB and having Wi Fi port or 3G capability. These notebooks are now becoming famous in the field of education and become the part of lifestyle. Due to its compact size and light weight, the school children are using it as ICT tool for learning. Students can store e-books and other relevant data into their notebook rather than using traditional pen based system. With the usage  of touchscreen,  notebooks have given additional advantage to the notebook user. Touch screen provides the playful environment to the user and learning becomes rather than drudgery.

Notebooks offer several distinct advantages in educational settings. First, their compact size and weight make for an easy fit in student work areas. Similarly, the small size makes notebooks easier to carry than heavier, larger sized traditional laptops.  Despite the small size and price, notebooks are fully capable of accomplishing most school-related tasks, including word processing, presentations, access to the Internet, multimedia playback, and photo management.

NOTEBOOK

C) Tablet

Tablet is another processing device like Computer or Laptop. Imagine a computer without keyboard and mouse without optical drive or simply much more than a smartphone.

TABLET

In 2002, original equipment manufacturers released the first tablet PCs designed to the Microsoft Tablet PC specification. This generation of Microsoft Tablet PCs  were designed to run Windows XP Tablet PC Edition, the Tablet PC version of Windows XP.  According to a 2001 Microsoft definition of the term, "Microsoft Tablet PCs" are pen-based, fully functional  PCs with handwriting and voice recognition functionality (this functionality provides the facility to the user to run or instruct the computer with voice or speech command). Tablet is just like a Personal computer. Tablet PCs use the same hardware as normal laptops but add support for pen input. Most tablets are designed to operate with touch screen which provide the interactive environment to the user and provide palyful environment. A good operating system is the main component of the tablet. Popular tablet operating systems are  Honeycomb version of Google Android, mobile versions of Windows 7 and XP, and Apple's iPad OS. All of these operating systems have their own advantages, disadvantages and features. New Software type APPS are the main sofware for the tablets. These apps are available on the internet. Some are paid and some are free of cost. For example the Apple computer has introduced its tablet named as iPad in market having operating system iOS and having iTunes app Store to download the apps software on iPad tablet. A touchscreen of tablet is very perceptive control system.

Keyboards and Docks

Nevertheless, there are quite a few situations in which a tablet can benefit from the addition of a keyboard or keyboard-equipped docking station. While it's possible to type on the face of a tablet, an attached keyboard can make this process much easier. Tablets like the Asus Eee Transformer have optional docking stations with built in keyboards which cost extra, but can basically turn a tablet into a full-featured notebook. Apple also sells an optional keyboard for use with its iPad.

Cameras

Most of the current generation tablets also have forward and rear-facing cameras. These cameras are meant to make it easy to use video-conferencing apps(  like Skype or face time ) and to take a quick photo. It's another way that tablets differ from traditional computers. Since they're flat and portable, an included camera can be a great feature.
They're an ideal way to browse the web, read an eBook, or to play games. Tablets are a casual type of computer, although they do have professional applications (especially for doctors and lawyers). They can be extremely engaging and useful, especially as prices drop and the list of features provided by modern tablets continues to grow.

D)  Smart Phones

Today, we all are quite familiar, with the term Smartphone. It is a mobile phone with advanced computing capability. There is a computer inside the mobile phones.  Computer is a computing device which executes the gaming software and other application software (apps) in our mobiles. It includes features like WI FI, Bluetooth and infrared ports. These days about 90% of handset sales worldwide are of devices powered by Google’s Android and Apple iOS mobile operating systems. Sony, Blackberry, Motorola, T-Mobile, Nokia, Apple are a few such companies which have made Smartphones. The big advantage of Smartphone is that it allows people to stay connected with the internet everywhere. These devices provide the facilities to every class of users like chatting, calling video calling, email and browsing etc.

 E) Personal Digital Assistant

The Personal Digital Assistant or Digital Diary is a class of the Portable computers. The personal digital system has a limited use in terms of the tasks it can perform. Basically, personal digital computers are used for the purpose of storing small data such as telephone numbers, addresses etc. The Personal Digital Assistant does not possess the ability of processing complex commands. Unlike other portable devices like the laptops and sub notebooks, they do not have hard drives or facility to run DVD s, CD s or floppy. Nowadays PDAs come in improved versions with the facilities of colored screens and even music system. However, with the cell phone boom, PDA’s have lost a considerable market share.

            The following features mostly characterize the Digital Diary:

·         Digital diary does have small screen

·         A small QWERTY keyboard is integrerated with digital diary

·         Having small battery to provide the power.

            Personal Digital Assistant can serve you in several ways.

·         It can store phone numbers

·         We can use it as calculator

·         It can store addresses

·         It can store reminders

·         It does have calanders

·         It can store small tex memos

Now these days the digital diaries are obsolete from market. During 1990 they were  of larger use before the popularity of mobile phones. People usd this device in place of conventional diary to store data like addresses, email id, landline phone numbers, text memos, reminders or calanders etc. With comparisons of traditional diary it is compact, accurate and non tearable and easy to carry and easy to retrive and to search the data.

2.4.4 Supercomputers

Super computes are a type of machine having very fast processing speed. It is because of powerful hardware and and intelligent software which faclitiates the supercomputer speedy calculations. Due to its high speed processing ability they are used in nuclear research, petroleum research, in the field of biotechnology for DNA analysis, in pharaceutical science for molecular modelling , weather forecasting etc. It is different from main frame computer. They are special purpose computer. They are designed to serve a singular purpose.

A brief time line of the development of supercomputers has been given as follows:

·         1960s: Seymour Cray of Control Data Corporation (CDC) launches the Supercomputer systems.

·         1970s: Cray Research is founded by Seymour Cray after he leaves Control Data Corporation (CDC).

·         1985-1990: Cray's model of supercomputer takes over the market.

Before the 1970s, supercomputers were mostly run on scalar process principle. But in order to improve its efficiency of a super computer a number of new technologies were developed such as:

·         Striped Disks (RAID)

·         Vector Processing

·         Parallel File systems

·         Non-uniform memory access (NUMA)

·         Liquid Cooling

When the hardwares of the supercomputers are prepared to serve a special mathematical operation, they are called Special Supercomputers. Currently, there are many such types of supercomputers as the GRAPE for molecular dynamics and astrophysics, Deep Crack for cracking DES cipher, Deep Blue for playing chess, (source wikipedia) etc

2.5 Summary

The types of computers range from the Hybrid to the Analog types on the basis of principle of computing. On the basis of size and power of processing the computer is classified as Mainframe, Minicomputer, Microcomputer and Super computer. But in our daily life, we use microcomputers. So microcomputer is further elaborated into two categories Static and portable.  The computers you come across in the daily course of your day range from laptops, palmtops and towers, to desktop computers, to name a few. But the very word "computers" reminds one of the desktop computers used in offices or homes. Different categories of computers have been devised in keeping with our varied needs.

2.6 Glossary

CPU                  Centeral Processing unit

PDA                  Personal digital Assitant or Digital Diary

AMD                Advanced Micro Device

WAN                Wide Area Network

IBM                  International business Machine

UMPC              Ultra Mobile Personal Computer

VIA                   Virtual Interface Architecture .

USB                  Universal serial Bus

HTPC                Home Theater Personal Computer

PDP                  Programmed Data Processor

2.7 Suggested Answer to SAQ

Que:  What is difference between digital and analog computer?

The analog computer is almost an extinct type of computer these days. This computing device works on continuous range of values. The analog computers give approximate results since they deal with quantities that vary continuously. It generally deals with physical variables such as voltage, pressure, temperature, speed, etc

The digital computer is designed using digital circuits in which there are two levels for and input or output signal. These two levels are known as logic 0 and logic 1. Digital Computers can give the results with more accuracy and at a faster rate.

 Que:  Explain the various characteristics of mainframe computer?

·         They are big computer systems sensitive to temperature, humidity, dust etc.

·         Qualified & trained operators are required to operate them.

·         They have wide range of peripherals attached.

·         They have large storage capacity.

·         They can use wide variety of software

·         They are not user friendly.

·         They can be used for more mathematical calculations.

·         They are installed in large commercial places or government organizations.

Que:  Explain the various timeline for Super computer?

·         1960s: Seymour Cray of Control Data Corporation (CDC) launches the Supercomputer systems.

·         1970s: Cray Research is founded by Seymour Cray after he leaves Control Data Corporation (CDC).

·         1985-1990: Cray's model of supercomputer takes over the market.

Today, supercomputers are designed by such companies as HP, IBM and of course, Cray Inc. Supercomputer systems are now becoming almost the same as laptop computers and desktop systems.

Que: What are the features of PDA?

      The following features mostly characterize the Digital Diary:

·         A small screen.

·         A small-integrated keyboard similar to the form of your Desktop computer.

·         An electronically active keypad capable understanding handwriting.

·         A tablet battery runs it.

2.8 References/Bibliography

·         Fundamental of Computer by V.Rajaraman , Published by PHI Publication

·         Fubdamental of Computer graphics and Multimedia by Dipti Parsad Mukrjee Published by PHI of India Pvt Ltd.

·         Computer Fundamental by Anita Goel Published by Persaon Education

·         Fundamental of computer for undergraduate courses by ITL Edication solution Ltd.    Published by Pearson Education India .

·         http://www.amd.com/us/aboutamd/corporate-information/Pages/timeline.aspx

·         http://www.amd.com/us/products/Pages/processors.aspx

·         http://www.computerbasicsguide.com/basics/types.html

·         http://www.mapsofworld.com/referrals/computers/types-of-computers/

2.9 Suggested Readings

·         Fundamental of Computer by V.Rajaraman , Published by PHI Publication

·         Fubdamental of Computer graphics and Multimedia by Dipti Parsad Mukrjee Published by 

·         PHI of India Pvt Ltd.

·         Computer Fundamental by Anita Goel Published by Persaon Education

·         Fundamental of computer for undergraduate courses by ITL Edication solution Ltd.   

·         Published by Pearson Education India .

2.10 Review Questions

·         Explain the various types of computer on the basis of principle of computing?

·         Difference between digital and analog computer?

·         Explain the various types of computer on the basis of power of processing?

·         Difference between Mainframe and Super computer?

·         What is difference between Ultra mobile PC and Home Theater PC?

·         What are different types of Portable Microcomputers?

·         Write about Static microcomputer?