Chapter 1 – Fundamentals of Computer

C – Commonly;  O – Oriented;  M – Machine;  P – Particularly;  U – Used;

T – for Trade; E – Education;  R – and Research.

Concept of Computer System

A computer is an advanced electronic device that takes raw data as input from the user and processes this data under the control of set of instructions (called program) and gives the result (output) and saves output for the future reference and usage.

To know about the working of a computer, first need to understand various terms such as Data, Processing and Information. First of all, lets start with three basic terms:-

basic Computer System

  1. Data  : Data is a collection of basic facts and figure without any sequence. This data is also called as raw data. When the data is collected as facts and figures, there is  no meaning to it, at that time, for example, name of people, names of employees etc.
  2. Processing : Processing is the set of instructions given by the user to the related data that was collected earlier to output meaningful information. The computer does the required processing by making the necessary calculations, comparisons and decisions.
  3. Information : Information is the end point or the final output of any processed work. This meaningful output data  is called information.
Fundamentals of Computer Characteristics of Computer

The major characteristics of computers are the following:

  • Speed : A powerful computer is capable of executing about 3 million calculations per second.
  • Accuracy : A computer’s accuracy is consistently high; if there are errors, they are due to errors in instructions given by the programmer.• Reliability : The output generated by the computer is very reliable as long as the data is reliable.
  • Memory/Storage Capacity : The computer can store large volumes of data and makes the retrieval of data an easy task.
  • Versatility : The computer can accomplish many different things. It can accept information through various input-output devices, perform arithmetic and logic operations, generate a variety of outputs in a variety of forms, etc.
  • Automation : Once the instructions are fed into computer it works automatically without any human intervention.
  • Diligence : A computer will never fail to perform its task due to distraction or laziness.
  • Convenience : Computers are usually easy to access, and allow people to find information easily that without a would be very difficult.
  • Flexibility : Computers can be used for entertainment, for business, by people who hold different ideals or who have varied goals. Almost anyone can use a computer,and computers can be used to assist with almost any goal.
Goals of Computers
  1. Problem-solving techniques using the computer.
  2. Analysis of complex problems and the synthesis of solutions .
  3. Comprehension of modern software engineering principles.
  4. A vast breadth and depth of knowledge in the discipline of computer science.
Computer Capabilities

⇒ Like all machines, a computer needs to be directed and controlled in order to perform a task successfully. Until such time as a program is prepared and stored in the computer’s memory, the computer ‘knows’ absolutely nothing, not even how to accept or reject data. Even the most sophisticated computer, no matter how capable it is, must be told what to do. Until the capabilities and the limitations of a computer are recognized, its usefulness cannot be thoroughly understood.

⇒ In the first place, it should be recognized that computers are capable of doing repetitive operations.  A computer can perform similar operations thousands of times, without becoming bored, tired, or even careless.

Secondly, computers can process information at extremely rapid rates.  For example, modern computers can solve certain classes of arithmetic problems millions of times faster than a skilled mathematician.  Speeds for performing decision-making operations are comparable to those for arithmetic operations but input-output operations, however, involve mechanical motion and hence require more time. On a typical computer system, cards are read at an average speed of 1000 cards per minute and as many as 1000 lines can be printed at the same rate.

Thirdly, computers may be programmed to calculate answers to whatever level of accuracy is specified by the programmer.  In spite of newspaper headlines such as ‘Computer Fails’, these machines are very accurate and reliable especially when the number of operations they can perform every second is considered.  Because they are man-made machines, they sometimes malfunction or break down and have to be repaired.  However, in most instances when the computer fails, it is due to human error and is not the fault of the computer at all.

⇒ In the fourth place, general-purpose computers can be programmed to solve various types of problems because of their flexibility.  One of the most important reasons why computers are so widely use today is that almost every big problem can be solved by solving a number of little problems-one after another.

Finally, a computer, unlike a human being, has no intuition.  A person may suddenly find the answer to a problem without working out too many of the details, but a computer can only proceed as it has been programmed to.

History of the Development of Computers
In beginning, there were no computers. To add or subtract , man used his fingers and toes. Abacus is known to be the  first mechanical calculating device. The main purpose of abacus was that additions and subtraction could be performed quickly. Abacus was developed by the Egyptians in the 10th centuary B.C, but the final structure was given in the 12th centuary A.D. by the Chinese educationists.  Abacus is made up of a frame in which rods are fitted across with rounds beads sliding on the rod.


Napier’s Bones in an Abacus invented by John Napier.Napier’s used the bone rods for counting purpose where numbers were printed on them. With the help of these  rods ,one could do addition, subtraction, multiplication and division speedy.

Pascal’s calculator called ‘Pascaline’

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. Though these machines were early forerunners to computer engineering, the calculator failed to be a great commercial success.

Leibniz Calculator

Leibniz was successfully introduced as a calculator onto the market in the year 1646. It was designed further in 1673 but it took until 1694 to complete. The calculator could perform the basic mathematical operations such as  add, subtract, multiply, and divide. Wheels were placed at right angles which could be displaced by a special stepping mechanism.

Analytical Engine “The First Computer”

This analytical engine, the first fully-automatic calculating machine, was constructed by British computing pioneer Charles Babbage (1791-1871), who first conceived the idea of an advanced calculating machine to calculate and print mathematical tables in 1812. This Analytical Engine incorporated an arithmetic logic unit, control flow in the form of conditional branching and loops, and integrated memory, making it the first design for a general-purpose computer that could be described in modern terms as Turing-complete.

Five Generations of Computers

First Generation of Computers (1942-1955)

The beginning of commercial computer age is from UNIVAC (Universal Automatic Computer). The first generation computers were used during 1942-1955. They were based on vacuum tubes. Examples of first generation computers are ENIVAC and UNIVAC-1.

• Vacuum tubes were the only electronic component available during those days.
• Vacuum tube technology made possible to make electronic digital computers.
• These computers could calculate data in millisecond.
• The computers were very large in size.
• They consumed a large amount of energy.
• Non-portable.
• Limited commercial use.
• Very slow speed.
• Used machine language only.
• Used magnetic drums which provide very less data storage.
Second Generation Computers

The second generation computers (1955-1964) used transistors. The size of the computers was decreased by replacing vacuum tubes with transistors. The examples of second generation computers are IBM 7094 series, IBM 1400 series and CDC 164 etc.

• Smaller in size as compared to the first generation computers.
• Used less energy and were not heated.
• Better speed and could calculate data in microseconds
• Used faster peripherals like tape drives, magnetic disks, printer etc.
• Used Assembly language instead of Machine language.
• Cooling system was required
• Constant maintenance was required
• Only used for specific purposes
• Costly and not versatile
Third Generation Computers

The Third generation computers(1964 – 1975) used the integrated circuits (IC).

The first IC was invented and used in 1961. The size of an IC is about ¼ square inch. A single IC chip may contain thousands of transistors. The computer became smaller in size, faster, more reliable and less expensive. The examples of third generation computers are IBM 370, IBM System/360, UNIVAC 1108 and UNIVAC AC 9000 etc.

An integrated circuit (IC), sometimes called a chip or microchip, is a semiconductor wafer on which thousands or millions of tiny resistors, capacitors, and transistors are fabricated.
• Smaller in size as compared to previous generations.
• More reliable.
• Used less energy.
• Better speed and could calculate data in nanoseconds.
• Air conditioning was required.
• Highly sophisticated technology required for the manufacturing of IC chips.
Fourth Generation Computers (1975 - Present)

The fourth generation computers started with the invention of Microprocessor. The Microprocessor contains thousands of ICs.  The LSI (Large Scale Integration) circuit and VLSI (Very Large Scale Integration) circuit was designed. It greatly reduced the size of computer. The size of modern Microprocessors is usually one square inch. It can contain millions of electronic circuits. The examples of fourth generation computers are Apple Macintosh & IBM PC.

• More powerful and reliable than previous generations.
• Small in size
• Fast processing power with less power consumption
• Fan for heat discharging and thus to keep cold.
• Cheapest among all generations
• All types of High level languages can be used in this type of computers
• The latest technology is required for manufacturing of Microprocessors.

Fifth Generation Computers (Present & Beyond)

Scientists are working hard on the 5th generation computers with quite a few breakthroughs. It is based on the technique of Artificial Intelligence (AI). Computers can understand spoken words & imitate human reasoning. IBM Watson computer is one example that outsmarts Harvard University Students.

Types of Computers

Computers can be classified according to the following types:

Based on Work


The analog computers are computer systems that measure variations in quantities such as temperature, voltage, speed, etc.  Analog computers are known to measure the data that varies continuously. Other examples of analog computers include Voltmeter and Ammeter.


Digital computers are the computer systems that count things by manipulation of certain discontinuous numbers and letters through representation of binary digits (also called bits) in contrast to analog computers that measures the variations in quantities). In other words texts and graphics are treated numerically. Today the digital computers have replaced the analog ones . Examples of digital computers are desktop , personal computers, work stations, tablet PC etc.


Hybrid computers as the name suggests are a good mix of analog as well as digital computers, using an analog computer front-end, which is then fed into a digital computer’s repetitive process. Hybrid computers are used for scientific calculations, in defence and systems.

Based on Purpose

On the basis of purpose, computers are categorised as following

General Purpose

These computers are designed to work on different types of applications. In these types of computers the programs are not stored permanently rather programs are input at the time of their execution. Personal computers, including desktops, notebooks, smart phones and tablets, are all examples of general-purpose computers. Various tasks can be accomplished by using general purpose computers : For example writing and editing (word processing), manipulating different facts and figures in various databases, tracking manufacturing inventory, making scientific calculations, controlling organization’s security system, electricity consumption, building temperature etc.

Special Purpose

Special-Purpose computers are task specific computers and are designed to solve a particular problem. They are also known as dedicated computers, because these computers are dedicated to perform a single particular task repetitively. Examples of such computer systems include the traffic control system ,they are also used in video games ,navigational systems in an aircraft, weather forecasting, satellite launch tracking, oil exploration,and in automotive industries, keeping time in a digital watch, or Robot helicopter.

Based on memory Size and Performance

Computers can be generally classified by size and power as follows –

Micro Computer

A microcomputer is a computer that uses  a microprocessor as its central processing unit. Microcomputers are physically smaller in size as  compared to mainframe and minicomputers. Many microcomputers when equipped with a keyboard and screen for input and output respectively can be used as personal computers (in the generic sense) .Microcomputers are easier to use and also inexpensive as the memory used by them i.e microprocessors and semi conductors have become cheaper in the last few years.

E.g. : The various micro computers widely available are IBM pcs , APPLE mac etc.the small types of pcs like the palmtop and handheld are now becoming available.


It is a midsize computer. In the past few years the difference between large minicomputers and small mainframes has decreased significantly just like the distinction between small minicomputers and work stations. A mini computer can support up to 200 users at the same time.

E.g. : The various machines widely available are vax series 8200 and 8300, honey well (xps-100), icl’s series 36 level 20,50,60 galaxy-21, hcl-4, nelco-5000 and others.


Mainframe computers known as the “Big Iron”  are computers that are used primarily by corporate and governmental organizations . Modern mainframe design is generally defined by the following features:

  • High reliability and security
  • Extensive input-output facilities with the ability to offload to separate engines
  • Strict backward compatibility with older version of software


Supercomputer is a term used for one of the fastest computers that exist today. They are deployed for specialized applications that require processing of highly critical data and immense amounts of mathematical calculations.

E.g. : Weather forecasting requires a supercomputer.

PARAM is a series of supercomputers designed and assembled by the Centre for Development of Advanced Computing (C-DAC) in Pune, India. The latest machine in the series is the PARAM Yuva II.

• China’s vast Tianhe-2 is the fastest supercomputer in the world.

Personal Computers

Personal Computers are computers that are designed for  an individual user. These computers are  small and a relatively cheaper. In price, personal computers can range anywhere from a few hundred pounds to over five thousand pounds. Personal Computers use the microprocessor technology as they enable manufacturers to put an entire CPU onto one chip. They serve myriad purposes and can be put to use by various businesses for word processing, accounting, desktop publishing, and for running spreadsheet and database management applications. People across the  globe use internet for playing games,surfing net and other online applications at their homes and personal use.

Types of  Personal Computers

Personal computers can be classified on the basis of its size. There are two basic types of the traditional designs i.e the  desktop models and tower models. There are several variations on these two basic types also.

Tower model

This model of personal computer refers to a computer in which the power supply, motherboard, and other mass storage devices are stacked on top of each other in a cabinet.

Desktop model

Desktop model means computer that are designed to fit comfortably on top of a desk, with the monitor sitting on top of the computer. Desktop model computers as compared to the tower model are broad and low, whereas tower model computers are narrow and tall.

Notebook computer

Also called ultra book. These are extremely popular because they are extremely lightweight and portable. Because of their small size ,typically less than 6 pounds or lesser than that,they have become so popular. These flat-panel technologies can produce a lightweight and non-bulky display screen. The quality of notebook display screens also differs considerably. Modern notebook computers are very similar to personal computers in terms of computing power.

Laptop computer

Laptop are now a days also called  notebook computers .These are small and portable .You can make them sit on your lap and work on them.

Subnotebook computer

Subnotebook computers are portable computers that are even lighter and smaller than a full-sized notebook computer. They are light weight because they use a small keyboard and screen as compared to a notebook computer.

Hand-held computer

These computers are portable enough to be carried in one’s hand. They are extremely convenient for use but due to extremely small size of their keyboards and screens they have still not succeeded in to replacing notebook computers.


These computers as the name suggest fit in your palm. Due to extremely small size their use is limited to phone books and calendars .


PDA’s have electronic pens rather than keyboards for inputs unlike laptop. They also incorporate handwriting recognition features. and voice recognition technologies i.e can also react to voice input . PDAs are also called palmtops, hand-held computers and pocket computers.

Smart phones

Smart phones are cellular phones that function both as a phone and a small pc. They may use a pen or may have a small keyboard. They can be connectedto the internet wirelessly. Apple, Samsung, Sony are some manufacturers of smart phones.

Uses of Computers

Computers have their application or utility everywhere. Some of the prominent areas of computer applications are:

In the Field of Education

Computers have taken the education systems in the entire world to a different level altogether. Following are the uses of computers in education-

  1. Making classrooms effective : The traditional classes have become modern and high-tech with the advent of computers. Students now see multimedia presentations, clips, images, etc. with the help of computers. This gives them a better experience of education as compared to the monotonous blackboard teaching. This way, the power of students to remember or recollect the taught concepts increases as the classroom learning becomes interesting.
  2. Providing online education : Computers not only strengthen the traditional education system but also provide a new mode of pursuing educational courses and degrees. This mode is called as online training mode of education. Online education system offers several benefits to the students which they can’t avail in traditional education system.
  3. Helps in research work : Computers help students of schools, colleges and universities in their research works. Gone are the days when students would go to libraries, and other Knowledge processing units to complete their research work. With the help of computers students now pursue their research work with ease and get ample amount of information for the same with easy clicks.

In the Field of Office

1. Document Management system  :  Document Management system consists of different applications like word processing, desktop publishing, spreadsheets etc.

Word Processing : is used to create documents electronically. It is used to produce high-quality letters, proposals, reports and brochures etc.
Desktop Publishing : is used to make these documents attractive with photos and graphics etc. it is used to publish the documents.
Spreadsheet Application : is used to maintain records and calculate expenses, profits and losses. It is also used to perform mathematical, statistical and logical processing.

2. Office Support System: It is used to coordinate and manage the activities of a work group. The members of a work group can share their work and coordinate with one another. Groupware and desktop organizers are examples of this system.

In the Field of Medicine

  1. Hospital Administration : Hospital is an important organization. We can use computer for the administration of a hospital. We can computerize the accounting, payroll and stock system of the hospital. We can keep the record of different medicines, their distribution and use in different wards etc.
  2. Recording Medical History : Computer can be used to store medical history of patients. We can store important facts about patients in computer we can keep record if his past treatment, suggested medicines and their results. Such systems can be very effective and helpful for doctors.
  3. Monitoring systems : Some serious patients must be monitored continuously. Monitoring is needed especially in operation theatres and intensive care units. Many computerized device are used to monitor the blood pressure, heartbeat and brain of the patients.
  4. Life Support System : life support systems are used to help the disabled persons. Many devices are used that help deaf person to hear, scientists are trying to create a device to help blind person to see.
  5. Diagnosis of Diseases : Different software are available to store data about different diseases and their symptoms. Diagnosis of disease is possible by entering the symptoms of a patient. Different computerized devices are used in laboratories for different tests of blood.

In the Field of Defence

There are many uses computers in defence such as:

  1. Computers are used to track incoming missiles and help slew weapons systems onto the incoming target to destroy them.
  2. Computers are used in helping the military find out where all their assets are (Situational Awareness) and in Communications/Battle Management Systems.
  3. Computers are used in the logistic and ordering functions of getting equipment to and around the battlefield.
  4. Computers are used in tanks and planes and ships to target enemy forces, help run the platform and more recently to help diagnose any problems with the platforms.
  5. Computers are used as gateways between different computer networks and to host security functions (crypto  systems).