Computer Basics : Evolution of Computers, Generation and Classification of Computers Application of Computers and etc.

1. Fundamental of Information Technology
Unit-I
[Computer Basics : Evolution of Computers, Generation and Classification of Computers,
Application of Computers and etc.]
Introduction
The term Computer is derived from ‘compute’ which means ‘to calculate’. Technically, it can be
defined as an electronic device which processes given data to derive the required and useful
information. During the processing the computer has to perform various functions like:
• receives data(input)
• processes data(process)
• produces output(information)
• stores results (storage)
These functions are described in the following block diagram :
1. Input: This is the process of entering data and programs in to the computer system.
Therefore, the input unit takes data from us to the computer in an organized manner for
processing through an input device such as keyboard, mouse, MICR (Magnetic Ink
Character Recognition), Etc.,
2. Main Memory: It is also known as internal memory. It is very fast in operation. It is used to
store data and instructions. Data has to be fed into the system before the actual processing
starts. It contains a part of the operating system Software, one or more execution programs
being executed, the data being processed and required by the programs for execution , and
processed data as output or result.
3. Output: This is the process of producing results from the data for getting useful
information. Similarly the output produced by the computer after processing must also be
kept somewhere inside the computer before being given to user in human readable form
through the screen or printer. Again the output is also stored inside the computer for further
processing.
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2. Fundamental of Information Technology
4. Control Unit (CU) : The next component of computer is the Control Unit, which acts like
the supervisor seeing that things are done in proper fashion. Control Unit is responsible for
co-ordinating various operations using time signal. The control unit determines the sequence
in which computer programs and instructions are executed. It also acts as a switch board
operator when several users access the computer simultaneously. Thereby it coordinates the
activities of computer’s peripheral equipment as they perform the input and output.
5. Arithmetic Logical Unit (ALU) : After you enter data through the input device it is stored
in the primary storage. The actual processing of the data and instruction are performed by
Arithmetic Logical Unit. The major operations performed by the ALU are addition,
subtraction, multiplication, division, logic and comparison. Data is transferred to ALU from
storage unit when required. After processing the output is returned back to storage unit for
further processing or getting stored.
6. Secondary storage: It is also known as auxiliary memory. It is closely linked with the main
memory. Since main memory can’t be flooded with unwanted data at particular moment,
same is stored in auxiliary memory from which desired data is fed to main memory as and
when required by it. Thus secondary storage is used to hold mass of information i.e., system
software, application programs, cinemas, games and data files. Obviously the capacity of
secondary storage is very high compared to main memory. Auxiliary memory usually in the
form of Magnetic disk, Magnetic tape, CD’s, Memory cards, Pen drives Etc.,
Characteristics of Computer :
The characteristics which make computer indispensable (essential) are:
1. Speed: The computer is able to process the data and gives the output in fractions of seconds,
such that required information is given to the user on time enabling the user to take right
decisions on right time. A powerful computer is capable of executing about 3 million
calculations per second.
2. Accurancy: The accuracy of computers is consistently high enough which avoids any
errors. If there are any errors, they are due to errors in instructions given by the programmer.
3. Reliable: The output generated by the computer is very reliable, but it is reliable only when
the data, which is passing as input to the computer and the program, which gives
instructions are correct and reliable.
4. Storage Capacity: The computer has a provision to store large volumes of data in the small
storage devices, which have capacity to store huge amounts of data and help the retrieval of
data an easy task.
5. Versatile: Computers are very versatile machines. Computers are capable of performing
almost any task ,provided the task can be reduced to a series of logical steps.
6. Automation: Once the instructions fed into computer it works automatically without any
human intervention until the completion of execution of program or meets logical
instructions to terminate the job.
7. Diligent (untiring): A computer is free from tiredness, lack of concentration, fatigue, etc. It
can work for hours without creating any error. If millions of calculations are to be
performed, a computer will perform every calculation with the same accuracy. Due to this
capability it overpowers human being in routine type of work.
8. No Feeling: It does not have feelings or emotion, taste, knowledge and experience. Thus, It
does not distinguish between users.
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Disadvantages of computer :
The use of computer has also created some problems in society which are as follows.
• Unemployment: Different tasks are performed automatically by using computers. It
reduces the need of people and increases unemployment in society.
• Wastage of time and energy: Many people use computers without positive purpose. They
play games and chat for a long period of time. It causes wastage of time and energy. Young
generation is now spending more time on the social media websites like Facebook,
Twitter etc or texting their friends all night through smartphones which is bad for both
studies and their health. And it also has adverse effects on the social life.
• Data Security: The data stored on a computer can be accessed by unauthorized persons
through networks. It has created serious problems for the data security.
• Computer Crimes: People use the computer for negative activities. They hack the credit
card numbers of the people and misuse them or they can steal important data from big
organizations.
• Privacy violation: The computers are used to store personal data of the people. The privacy
of a person can be violated if the personal and confidential records are not protected
properly.
• Health risks: The improper and prolonged use of computer can results in injuries or
disorders of hands, wrists, elbows, eyes, necks and back. The users can avoid health risks by
using the computer in proper position. They must also take regular breaks while using the
computer for longer period of time. It is recommended to take a couple of minutes break
after 30 minutes of computer usage.
• Impact on Environment: The computer manufacturing processes and computer waste are
polluting the environment. The wasted parts of computer can release dangerous toxic
materials. Green computer is a method to reduce the electricity consumed and
environmental waste generated when using a computer. It includes recycling and regulating
manufacturing processes. The used computers must be donated or disposed off properly.
Evolution of Computers
When our ancestor started using stone to count their animals or the possession they never knew that
it will lead to a computer of today. The first calculating device invented many centuries ago was
know as ABACUS.
THE ABACUS
Abacus is known to be the first mechanical calculating device. Which was used to be performed
addition and subtraction easily and speedily? This device was a first develop Ed by the Egyptians in
the 10th century B.C, but it was given it final shape in the 12th century A.D. by the Chinese
educationists.
Abacus is made up of wooden frame in which rod where fitted across with rounds beads sliding on
the rod. It id dividing into two parts called ‘Heaven’ and ‘Earth’. Heaven was the upper part and
Earth was the lower one. Thus any no. can be represented by placing the beads at proper place.
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4. Fundamental of Information Technology
NAPIER’S BONES
As the necessity demanded, scientist started inventing better calculating device. In thus process
John Napier’s of Scotland invented a calculating device, in the year 1617 called the Napier Bones.
In the device, Napier’s used the bone rods of the counting purpose where some no. is printed on
these rods. These rods that one can do addition, subtraction, multiplication and division easily.
PASCAL’S CALCULATOR
In the year 1642, Blaise Pascal a French scientist invented an adding machine called Pascal’s
calculator, which represents the position of digit with the help of gears in it.
LEIBNZ CALCULATOR
In the year 1671, a German mathematics, Gottfried Leibniz modified the Pascal calculator and he
developed a machine which could perform various calculation based on multiplication and division
as well.
ANALYTICAL ENGINE
In the year 1833, a scientist form England knows to be Charles Babbage invented such a machine.
Which could keep our data safely? This device was called Analytical engine and it deemed the first
mechanical computer.
It included such feature which is used in today’s computer language. For this great invention of the
computer, Sir Charles Babbage is also known as the father of the computer.
Geneartion of Computers
As the time passed, the device of more suitable and reliable machine was needed which could
perform our work more quickly. During this time, in the year 1946, the first successful electronic
computer called ENIAC was developed and it was the starting point of the current generation of
computer.
The present day computer, however, has also undergone rapid changes during the last fifty years.
This period, during which the evolution of computer took place, can be divided into five distinct
phases known as Generations of Computers. Generation of computer means the technological
evolution (Hardware and software) over the period of time.
First Generation Computers (1946-59)
First generation computers used Thermion valves or Vacuum tubes. Because of vacuum tubes, these
computes were large in size, required lot of energy, slow in input/output, and suffered maintenance
problems. Further, the vacuum tubes needed to be replaced often as they had short life span. Writing
programs on them was difficult too.
ENIAC was the world first successful electronic computer which was develops by the two scientists
namely J. P. Eckert and J. W. Mauchy. The full form of ENIAC is “Electronic Numeric Integrated
And Calculator” ENIAC was a very huge and big computer and its weight was 30 tones. It could
store only limited or small amount of information. Other examples of this generation machine are
EDSAC – Electronic Delay Storage Automatic Calculator, EDVAC – Electronic Discrete
Variable Automatic Computer, UNIVAC – Universal Automatic Computer IBM 701.
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5. Fundamental of Information Technology
Followings were the major drawbacks of first generation computers.
• They were quite bulky.
• The operating speed was quite slow.
• Power consumption was very high.
• It required large space for installation.
• They had no operating system.
• The programming capability was quite low.
Second Generation Computers (1959-64)
Around 1959 an electronic device called Transistor replaced the bulky vacuum tubes in the first
generation computer. A single transistor contained circuit produced by several hundred vacuum
tubes. Thus the size of the computer got reduced considerably. Transistors therefore provided higher
operating speed than vacuum tubes. They had no filament and require no heating. Manufacturing
cost was also very low. It is in the second generation that the concept of Central Processing Unit
(CPU), memory, programming language and input and output units were developed. The
programming languages such as COBOL, FORTRAN were developed during this period. Some of
the computers of the Second Generation were:
IBM 1920 : Its size was small as compared to First Generation computers and mostly used for
scientific purpose.
IBM 1401 : Its size was small to medium and used for business applications.
CDC 3600 : Its size was large and used for scientific purpose.
The salient features of this generation were:
• relatively faster than the first generation computers.
• smaller than the first generation computers
• generated lower level of heat
• more reliable
• higher capacity of internal storage
Third Generation Computers (1964-71)
The third generation computers were introduced in 1964. They used Integrated Circuits (Ics). A
single IC has many transistors, resistors and capacitors built on a single thin slice of silicon. This
not only increased the speed of computers but also made them smaller, more powerful, and less
expensive. In addition, instead of the punch cards and the printouts of previous systems, keyboards
and monitors were now allowing people to interact with computing machines. So it is quite obvious
that the size of the computer got further reduced. Some of the computers developed during this
period were IBM-360, ICL-1900, IBM-370, and VAX-750. Higher-level language such as BASIC
(Beginners All purpose Symbolic Instruction Code) was developed during this period.
The features of computers belonging to this generation were:
• used tiny ICs
• relatively very small in size
• made use of operating system
• high processing speed
• more reliable
• power efficient and high speed
• use of high level languages
• large memory
• low cost
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Fourth Generation Computers (1971 onwards)
The present day computers that you see today are the fourth generation computers that started
around 1975. It uses Large Scale Integrated Circuits (LSIC) built on a single silicon chip called
micro-processors. Due to the development of microprocessor it is possible to place computer’s
central processing unit (CPU) on a single chip. These computers are called microcomputers. Later
very large scale Integrated Circuits (VLSIC) replaced LSICs. These integrated circuits are so
advanced that they incorporate hundreds of thousands of active components in volumes of a fraction
of an inch.
Thus the computer, which was occupying a very large room in earlier days, can now be placed on a
table. The personal computer (PC) that you see in your school is a Fourth Generation Computer.
Personal computers and their ability to create networks eventually would lead to the Internet in the
early 1990s. The fourth generation of computers also saw the creation of even smaller computers
including laptops and hand-held devices. Graphical user interface, or GUI, was also invented during
this time. Computer memory and storage also went through major improvements, with an increase
in storage capacity and speed. Examples are IBM PC and Apple II. The fourth generation computers
also include super computers such as CRAY series computers. Super computers are the best in
terms of processing speed (billions of instructions per second). They are used for applications which
require intensive numerical computations such as stock analysis, weather forecasting and other
similar complex applications.
The salient features of this generation are:
• very fast
• very low heat generation
• smaller in size
• very reliable
• negligible hardware failure
• highly sophisticated
Fifth Generation Computers (Present and beyond)
The computers, which can think and take decisions like human beings have been characterized as
Fifth generation computers and are also referred as thinking machines. The speed is extremely high
in fifth generation computer. Apart from this they can perform parallel processing. The concept of
Artificial Intelligence has been introduced to allow the computer to take its own decision. It is still
in a developmental stage, though there are some applications, such as voice recognition, that are
being used today.
The use of parallel processing and superconductors is helping to make artificial intelligence a
reality. Quantum computation and molecular and nanotechnology will radically change the face of
computers in years to come. The goal of fifth-generation computing is to develop devices that
respond to natural language input and are capable of learning and self-organization. A lot of
research and development work is going on in this area in United States and Japan but it will take
some time before such machines are produced for use by the industry. IBM notebooks, Pentium Pcs
and PARAM 10000 are example of the fifth generation computers.
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Summary of Generation of Computers:
Classification of Computers
In general computers are classified into major categories based on.
• According to the purpose of the computer.
• According to the operation of computer.
• According to the size of computer.
(a) Classification as per purpose of the computer
1. General purpose computers.
2. Special purpose computer.
General Purpose Computers : These computers are theoretically used for any type of
applications. These computers can be used in solving a business Problem and also used to
solve mathematical equation with same accuracy and consistency. Most of the computer
now are general purpose digital computers. For example, all the P.C’s, which are used as
home computer.
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Special Purpose Computers : These digital computer are designed, made and used for any
specific job. These are usually used for those purposes which are critical and need great
accuracy and response like Satellite launching, weather forecasting etc.
(b) Classification according to the operation of computer
1. Analog Computers
2. Digital Computers
3. Hybrid Computers
Analog Computers: An analog computer operates on inputs of continuously varying
electrical voltages. These are different from a digital computer because an analog computer
can perform several mathematical operations simultaneously. It uses continuous variables
for mathematical operations and utilizes mechanical or electrical energy. These are used
mainly in scientific design and production environments. Each one has to be constructed to
do a specific job and will respond very quickly to changes in the measurement of inputs.
Examples: Thermometer, Speedometer etc.
Digital Computers: They use digital circuits and are designed to operate on two states
namely bits 0 and 1. They are analogous to states ON and OFF. Data on these computers is
represented as a series of 0s and 1s. Digital computers are suitable for complex computation
and have higher processing speeds. They are programmable. Digital computers are either
general purpose computers or special purpose ones. Special purpose computers, as their
name suggests, are designed for specific types of data processing while general purpose
computers are meant for general use. These computers are widely used in commercial and
control systems. Now a days when we use the word computer, we mostly refer to a digital
computer.
Hybrid Computers: Hybrid computers are computers with combined features of both
digital and analog type. 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. In other words, the output can be either in the form of numbers or required units
of measurement. A hybrid computer system setup offers a cost effective method of
performing complex simulations. It is mostly used with process control equipments in
continuous production plants e.g., oil refineries. Other areas of application are nuclear
power plants, mines, intensive care units of hospitals (ICUs), chemical process plants
etc. For example an analog device measures patient’s heart beat (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 into digital signal).
(b) Classification as per the size of computer
1. Microcomputers
2. Minicomputers
3. Mainframe computers
4. Supercomputer
Microcomputers: A computer with a microprocessor and its central processing unit is
known as a microcomputer. When supplemented with a keyboard and a mouse,
microcomputers can be called personal computers. A monitor, a keyboard and other similar
input-output devices, computer memory in the form of RAM and a power supply unit come
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9. Fundamental of Information Technology
packaged in a microcomputer. These computers can fit on desks or tables and prove to be the
best choice for single-user tasks. IBM PC based on Pentium microprocessor and Apple
Macintosh are some examples of microcomputers. Microcomputers include desktop
computers, notebook computers or laptop, tabletcomputer, handheld computer, smart phones
and netbook.
Mini Computer: Minicomputers are mainly used as small or midrange servers operating
business and scientific applications. Minicomputers can support 4–200 users simultaneously.
The users can access the minicomputer through their PCs or terminal. It possesses large
storage capacity and operates at a high speed than a microcomputer. They are also used as
servers in Local Area Networks (LAN). Example Digital Alpha, Sun Ultra.
Mainframe computers: Mainframe computers are multi-user, multi-programming and high
performance computers. They operate at a very high speed, have very large storage capacity
and can handle the workload of many users. Mainframe computers are large and powerful
systems generally used in centralized databases. Computers with large storage capacities and
very high speed of processing (compared to mini or microcomputers) are known as
mainframe computers. They support a large number of terminals forsimultaneous use by a
number of users like ATM transactions. They are also used as central host computers in
distributed data processing system. Mainframe computers are used in organizations like
banks or companies, where many people require frequent access to the same data. Examples:
IBM 370, S/390.
Supercomputers: Supercomputers are the fastest and the most expensive machines. They
have high processing speed compared to other computers. The speed of a supercomputer is
generally measured in FLOPS (Floating point Operations per Second). Some of the faster
supercomputers can perform trillions of calculations per second. Supercomputers are used
for highly calculation-intensive tasks, such as, weather forecasting, climate research
(global warming), molecular research, biological research, nuclear research and aircraft
design. They are also used in major universities, military agencies and scientific research
laboratories. Some examples of supercomputers are IBM Roadrunner, IBM Blue gene and
Intel ASCI red. PARAM is a series of supercomputer assembled in India by C-DAC (Center
for Development of Advanced Computing), in Pune. PARAM Padma is the latest
Application of Computers
The various applications of computers in today's arena :
1. Business
2. Industry
3. Education
4. Marketing
5. Banking
6. Insurance
7. Communication
8. Health Care
9. Military
10. Engineering Design
11. Tourism
12. Transportation
13. Entertainment
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• Business: A computer has high speed of calculation, diligence, accuracy, reliability, or
versatility which made it an integrated part in all business organisations. Computer is used
in business organisations for: Payroll calculations, Sales analysis, Budgeting, Financial
forecasting, Managing employees database and Maintenance of stocks etc.
• Industry: Computers are finding their greatest use in factories and industries of all kinds.
They have taken over the work ranging from monotonous and risky jobs like welding to
highly complex jobs such as process control. Drills, saws and entire assembly lines can be
computerized. Moreover, quality control tests and the manufacturing of products, which
require a lot of refinement, are done with the help of computers. Not only this, Thermal
Power Plants, Oil refineries and chemical industries fully depend on computerized control
systems because in such industries the lag between two major events may be just a fraction
of a second.
• Education: Computers have its dominant use in the education field which can significantly
enhance performance in learning. Computers have proved to be excellent teachers. They can
possess the knowledge given to them by the experts and teach you with all the patience in
the world. You may like to repeat a lesson hundred times, go ahead, you may get tired but
the computer will keep on teaching you. Even distance learning is made productive and
effective through internet and video-based classes. Researchers have massive usage of these
computers in their work from the starting to till the end of their scholarly work.
• Marketing: In marketing, uses of computer are :
Advertising- With computers, advertising professionals create art and graphics,
write and revise copy, and print and disseminate ads with the goal of selling more
products.
Home Shopping- Home shopping has been made possible through use of
computerised catalogues that provide access to product information and permit
direct entry of orders to be filled by the customers.
• Banking: Banks also have started using computers extensively. Terminals are provided in
the branch and the main computer is located centrally. This enables the branches to use the
central computer system for information on things such as current balance, deposits,
overdrafts, interest charges, etc. MICR encoded cheques can be read and sorted out with a
speed of 3000 cheques per minute by computers as compared to hours taken by manual
sorting. Electronic funds transfer (EFT) allows a person to transfer funds through computer
signals over wires and telephone lines making the work possible in a very short time.
ATM machines are making it even easier for customers to deal with banks.
• Insurance: Insurance companies are keeping all records up-to-date with the help of
computers. The insurance companies, finance houses and stock broking firms are widely
using computers for their concerns.
• Communication: Communication means to convey a message, an idea, a picture or speech
that is received and understood clearly and correctly by the person for whom it is meant for.
Some main areas in this category are: Chatting, E-mail, Usenet, FTP, Video-conferencing
and Telnet.
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• Health Care: Most of the medical information can now be digitized from the prescription to
reports. Computation in the field of medicine allows us tooffer varied miraculous therapies
to the patients. ECG’s, radiotherapy wasn’t possible without computers.
• Military: Computers are the main tools which help in developing missiles and other
equipment in the deference system. Designing and the maintenance are possible only
through computers. Computer builds the links between the soldiers and commanders
through the satellite. Construction of weapons and controlling their function is not possible
without the aid of computers. The list of the criminals and the records of the cops are
maintained regularly in the system.
• Engineering Design: As per the title,computers aid in designing buildings, magazines,
prints, newspapers, books and many others. The construction layouts are designed
beautifully on system using different tools and software’s.
• Tourism: Hotels use computers to speed up billing and checkout the availability of rooms.
So is the case with railways and airline reservations for booking tickets. Architects can
display their scale models on a computer and study them from various angles and
perspectives. Structural problems can now be solved quickly and accurately.
• Transportation: Today computers have made it possible for planes to land in foggy and
stormy atmosphere also. The aircraft has a variety of sensors, which measure the plane’s
altitude, position, speed, height and direction. Computer use all this information to keep the
plane flying in the right direction. In fact, the Auto–pilot feature has made the work of pilot
much easy.
• Entertainment: Computers are also great entertainers. Many computer games are available
which are like the traditional games like chess, football, cricket, etc. Some games provide
the opportunity to test your memory and ability to think. Other games are designed to test
your knowledge.
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