Chapter-1 Fundamentals of Computers

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DeptDeptDeptDept ofofofof Computer Science, B.V.R.I.C.E.Computer Science, B.V.R.I.C.E.Computer Science, B.V.R.I.C.E.Computer Science, B.V.R.I.C.E.

FUNDAMENTALS OF COMPUTERS

Computer Science, B.V.R.I.C.E. Computer Science, B.V.R.I.C.E. Computer Science, B.V.R.I.C.E. Computer Science, B.V.R.I.C.E.

FUNDAMENTALS OF COMPUTERS

Unit

Unit----IIII

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2 FUNDAMENTALS OF COMPUTERS

FUNDAMENTALS OF COMPUTERS

Definition of a Computer

Computer is an electronic device; gets the data and instructions through input devices, process it as per the instructions given by the programmer/user and gives the information as

output through output devices.

Or

A computer is an electronic device, and it can perform arithmetic and logical operations accurately and effectively at high speed according to the set of instructions provided to it.

Or

Computer is an electronic device; it accepts the data as input, process the information and produces the output at high speed.

The terms used in the definition are defined as

_{Data – a set of basic facts and entities which itself has no meaning}

_{Information – processed data which has some meaning}

_{Instruction- a statement given to computer to perform a task}

_{Input- data and instructions given to computer}

_{Process – Manipulation of data}

_{Output- Information obtained after processing of data}

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Definition and Block Diagram of a Computer (Basic Computer Organization)

A computer is an electronic device with the ability to

1. Accept user supplied data and instructions.

2. Store the data and instructions.

3. Perform mathematical and logical operations at high speed.

4. Output results according to user specification.

The term computer has been borrowed from the word compute means to calculate .Now a days the computers are used nearly in every field like education, banking application, word processing, desktop publications, scientific research, weather forecasting, ticket reservations, control of robots etc.

Input unit:

Input unit contains several Input devices those are used to enter data and instructions into the computer. The input devices are connected to CPU. Data and Instructions are entered into a computer through an Input unit.eg: Data can be entered using a keyboard in a manner similar to typing and this is differs from the way in which data and instructions are entered through mouse.

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Output unit:

Output unit contains several output devices they are used give desired output/result to the user the output devices are also connected to CPU. Output unit supplies information obtained by processor to user we know the computer works with binary code and also the results produced by CPU is also in binary code therefore before supplying to user output devices need to transform binary form of result output to user understandable one.

Storage unit:

Before going to processing the data and instructions the computer system has to be stored inside the computer. Similarly after results produced that have to be kept somewhere inside the computer system.

The storage unit holds as following

• Data and instructions required for processing • Intermediate results of processing

• Results for output

Primary storage:

Primary storage is also called main memory or physical memory. It is used to hold pieces of programs or data or instructions to be execute in the CPU and also kept intermediate results and recently produced results until the power is off when the power off the system that storage can be erased. It has very less memory storage capacity. It is very costly and speed.

Ex: RAM, ROM

Secondary storage:

It is also called as Auxiliary storage. It is used to take care of the limitations of primary storage. It holds the data or information after processing by CPU. It has very large storage, slow access rate than primary memory, it is very cheaper. This is permanent memory so it is non volatile memory. When we need data for future use, it needs to be stored at secondary storage devices. Ex: HARD, CD, FLOPPY, etc.

Control unit:

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ALU:

The calculations and comparisons are performed according to the instructions on the data in Arithmetical and logic unit of the system. The data and instructions are taken from the main memory to perform arithmetical & logical operations. Intermediate and final results are again stored back into the main memory. Arithmetic operations are Addition, Subtraction, Multiplication, division and logical operations i.e.. >,<,>=,<=,==,!=

CPU:

Control unit and arithmetical logical unit of computer system are together known as the central processing unit (CPU). The CPU is brain of computer system. In a human body the brain takes all major decisions and other parts of the body functions as directed by brain. Similarly, in computer all major decisions take place inside CPU.

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Advantages and Disadvantages of a Computer (Characteristics of a Computer)

Computer is very powerful and useful tools to perform several operations. This is most popular tool because of its following characteristics.

Advantages

1. Automatic

2. Speed

3. Accuracy

4. Diligence

5. Versatility

6. Power of Remembering

Automatic:

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Speed:

A computer is very fast device. It can perform no. of tasks in few seconds, but a human being can do the same work in entire year. A modern computer executes instructions within Milliseconds (10-3), Microseconds (10-6), and Nanoseconds (10-9), Picoseconds (10-12). The cost of the computer depends on the speed at which it executes an instruction.

Accuracy:

Usually computers do not make any mistakes while computing. Due to human mistakes, like wrong formulate, wrong methodology, some wrong results may occur. But computers always process with high speed and gives exact and accurate values.

Diligence:

The computer is hard working device. It is free from dullness, tiredness and lack of concentration. It can work continuously for several hours without rest and Interrupt. Instead of 10000 men, a single computer can do the work for several hours continuously.

Versatility:

Computers can perform a variety of jobs like generating bills. They are capable of performing any task with high speed & accuracy. There is no limitation to single type of jobs. Computers are used in variety of applications.

Power of remembering:

Computer having the storage capacity to store information like a human being. So, computer can store the data or information in memory. But human being might be forgot, what they stored in their mind i.e. the power of remembering is very low. Whenever user needed data he can retrieve the data from computer memory.

Disadvantages

Following list demonstrates the disadvantages of computers in today's arena

No I.Q

• A computer is a machine that has no intelligence to perform any task.

• Each instruction has to be given to computer.

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Dependency

• It functions as per a user’s instruction, so it is fully dependent on human being

No Feeling

• Computers have no feelings or emotions.

• It cannot make judgment based on feeling, taste, experience, and knowledge unlike a human being.

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Generations of Computer

Generation in computer terminology is a change in technology a computer is/was being

used. Initially, the generation term was used to distinguish between varying hardware

technologies. But nowadays, generation includes both hardware and software, which together

make up an entire computer system.

Following are the main five generations of computers

S.N. Generation & Description

1 First Generation

The period of first generation: 1946-1959. Vacuum tube based.

2 Second Generation

The period of second generation: 1959-1965. Transistor based.

3 Third Generation

The period of third generation: 1965-1971. Integrated Circuit based.

4 Fourth Generation

The period of fourth generation: 1971-1980. VLSI microprocessor based.

5 Fifth Generation

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First Generation

The period of first generation was 1946-1959. The computers of first generation used

vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing

Unit). These tubes, like electric bulbs, produced a lot of heat. These are very expensive and

could be afforded only by very large organizations. In this generation mainly batch processing

operating system were used. Punched cards, paper tape, and magnetic tape were used as input

and output devices. The computers in this generation used machine code as programming

language.

Advantages

• They were the fastest calculating devices of their time.

Disadvantages

• Unreliable

• Supported machine language only

• Very costly

• Generated lot of heat

• Slow input and output devices

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• Need of A.C.

• Non-portable

• Consumed lot of electricity

Some computers of this generation were:

• ENIAC

• EDVAC

• UNIVAC

• IBM-701

• IBM-650

Second Generation

The period of second generation was 1959-1965. In this generation transistors were used

that were cheaper, consumed less power, more compact in size, more reliable and faster than the

first generation machines made of vacuum tubes. In this generation, magnetic cores were used as

primary memory and magnetic tape and magnetic disks as secondary storage devices. In this

generation assembly language and high-level programming languages like FORTRAN, COBOL

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Advantages

• Reliable in comparison to first generation computers

• Smaller size as compared to first generation computers

• Generated less heat as compared to first generation computers

• Consumed less electricity as compared to first generation computers

• Faster than first generation computers

Disadvantages

• These are manufactured using transistors, which had to be assembled manually.

• Still very costly

• A.C. needed

• IBM 1620

• IBM 7094

• CDC 1604

• CDC 3600

• UNIVAC 1108

Third Generation

The period of third generation was 1965-1971. The computers of third generation used

integrated circuits (IC's) in place of transistors. A single IC has many transistors, resistors and

capacitors along with the associated circuitry. The IC was invented by Jack Kilby. This

development made computers smaller in size, reliable and efficient. In this generation remote

processing, time-sharing, multi-programming operating system were used. High-level languages

(FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL-68 etc.) were used during

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Advantages

• They were faster than second generation computers and could perform one million

transactions per second.

• They were smaller, cheaper and more reliable than their predecessors.

• These computers had faster and larger primary memory and secondary storage.

• Widely used for scientific as well as business applications.

• High level programming languages were used.

• Remote, time sharing, multiprogramming operating systems were used.

Disadvantages

• These Computers were difficult to maintain. • They got heated very quickly.

• IBM-360 series

• Honeywell-6000 series

• PDP(Personal Data Processor)

• IBM-370/168

• TDC-316

Fourth Generation

The period of fourth generation was 1971-1980. The computers of fourth generation used

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other circuit elements and their associated circuits on a single chip made it possible to have

microcomputers of fourth generation. Fourth generation computers became more powerful,

compact, reliable, and affordable. As a result, it gave rise to personal computer (PC) revolution.

In this generation time sharing, real time, networks, distributed operating system were used. All

the high-level languages like C, C++, DBASE etc., were used in this generation.

Advantages

• These computers were smaller, cheaper, faster and more reliable than their predecessors.

• Consumed less electricity and generated less heat.

• They had faster and larger primary memory and secondary storage.

• Pipeline processing

• No A.C. needed

• Concept of internet was introduced

• Great developments in the fields of networks

• Computers became easily available

Disadvantages

• They are not intelligent syetms.

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• DEC 10

• STAR 1000

• PDP 11

• CRAY-1(Super Computer)

• CRAY-X-MP(Super Computer)

Fifth Generation

The period of fifth generation is 1980-till date. In the fifth generation, the VLSI

technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production

of microprocessor chips having ten million electronic components. This generation is based on

parallel processing hardware and AI (Artificial Intelligence) software. AI is an emerging branch

in computer science, which means method of making computers think like human beings. All

the high-level languages like C and C++, Java, .Net etc., are used in this generation.

AI includes:

• Robotics

• Neural Networks

• Game Playing

• Development of expert systems to make decisions in real life situations.

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DeptDeptDeptDept ofofofof Computer Science, B.V.R.I.C.E.Computer Science, B.V.R.I.C.E.Computer Science, B.V.R.I.C.E.Computer Science, B.V.R.I.C.E. The main features of fifth generation are:

• ULSI technology

• Development of true artificial intelligence

• Development of Natural language processing

• Advancement in Parallel Processing

• Advancement in Superconductor technology

• More user friendly interfaces with multimedia features

• Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are:

• Desktop

• Laptop

• NoteBook

• UltraBook

• ChromeBook

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Classification of Computers

Computers are classified into three categories and are as follows;

1. Classification of computers depending on type of data

2. Classification of computers according to processing speed and storage capacity

3. Classification of computers on the basis of applications

These are explained as follows;

1. Classification of computers depending on Type of Data

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DeptDeptDeptDept ofofofof Computer Science, B.V.R.I.C.E.Computer Science, B.V.R.I.C.E.Computer Science, B.V.R.I.C.E.Computer Science, B.V.R.I.C.E. a) Analog computers

b) Digital Computers

c) Hybrid Computers

a) Analog computers

Analog computers process data in a continuous form. The continuous data means the data may change time to time like temperature, pressure, volume, force, current, velocity, acceleration etc. The real time components thermometer, speedometers are working on this principle.

This computer has limited memory. Analog computers are used in chemical process where continuous measurement is needed.

b) Digital Computers

Digital computers accept numerical values and convert them into electric pulses and perform arithmetical operations.

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c) Hybrid Computers

Hybrid Computers process the capabilities of both the analog and as well as digital computers. These computers are used in hospitals to measure patient’s heartbeat and patient’s temperature.

2. Classification of computers according to Processing Speed and Storage Capacity

According to the size of memory and processing speed computers are classified as

a) Super Computers

b) Mainframe Computers

c) Mini Computers

d) Micro Computers

a. Supercomputer

The most powerful computers in terms of performance and data processing are the Supercomputers. These are specialized and task specific computers used by large organizations. These computers are used for research and exploration purposes, like NASA uses supercomputers for launching space shuttles, controlling them and for space exploration purpose.

The supercomputers are very expensive and very large in size. It can be accommodated in large air-conditioned rooms; some super computers can span an entire building.

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b. Mainframe Computer

Computers with large storage capabilities and very high speed of processing compared to micro and mini computers are known as mainframe computers. Mainframe computers can occupy an entire room. Mainframes are used by many banks, airlines, insurance companies, and big organizations etc. These computers are introduced in 1960’s.

c. Mini Computers

Minicomputers are used by small businesses & firms. Minicomputers are also called as “Midrange Computers”. These are small machines and can be accommodated on a disk with not as processing and data storage capabilities as super-computers & Mainframes.

These computers are not designed for a single user. Individual departments of a large company or organizations use Mini-computers for specific purposes. For example, a production department can use Mini-computers for monitoring certain production process.

Popular Minicomputers

• K-202

• Texas Instrument TI-990

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• IBM Midrange computers

d. Micro Computers

A computer designed using a microprocessor as its CPU is called a microcomputer. A microcomputer is also called personal computer. A microcomputer is the smallest and least expensive general processing system. These computers are based on the use of microprocessor.

Desktop computers, laptops, personal digital assistant (PDA), tablets & smart phones are all types of microcomputers. These computers are used in the pay roll preparation for employees training of students in college etc.

3. Classification of computers on the basis of Applications

Modern computers are classified into 2 categories. Depending on their applications as

a) Special Purpose Computers

b) General Purpose Computers

a) Special Purpose Computers

Special Purpose Computers are designed to perform a scientific application. The computers used in mining, air craft systems, an missile, guidance systems, fall under this category CAD (Computer Aided Designing), robotics design, and also used to control industrial robots.

b) General Purpose Computers

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Difference between Analog and Digital Computers

S.No

1 Analog Computers Work on continuous values.

Digital computers Work on discrete values.

2 Analog Computers have low memory.

Digital computers have a very large memory

3 Analog computers have Slow speed.

Digital computers have fast speed.

4 Analog computers are less reliable. Digital computers are more reliable.

5

Analog computers used in engineering and science and medical fields.

Digital computers are used in all fields of life.

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Analog computers are used to calculate / measure analog quantities like speed and temperature.

Digital computers are used to calculate mathematical and logical operations. It can solve addition, subtraction,

division, multiplication and other mathematical and statistical operations

7 Analog computers provide less accurate results.

Digital computers provide 100% accurate results.

8 Normally Analog Computers are specific purpose

Digital Computers are general purpose

9 Analog computers are difficult to use

Digital computers are easy to use

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Examples of Analog computers are: thermometer, analog clock,

speedometer etc.

Examples of digital computers are: Personal Computer, laptops, smart phones etc

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Applications of Computers

Following list demonstrates various applications of computers in today's arena.

Business

A computer has high speed of calculation, diligence, accuracy, reliability, or versatility which made it an integrated part in all business organizations.

Computer is used in business organizations for:

• Payroll calculations

• Budgeting

• Sales analysis

• Financial forecasting

• Managing employees database

• Maintenance of stocks etc.

Banking

Today banking is almost totally dependent on computer.Banks provide following facilities:

• Banks provide online accounting facility, which includes current balances, deposits, overdrafts, interest charges, shares, and trustee records.

• 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.

Insurance companies are maintaining a database of all clients with information showing

• procedure to continue with policies

• starting date of the policies

• next due installment of a policy

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• interests due

• survival benefits

• bonus

Education

The computer has provided a lot of facilities in the education system.

• The computer provides a tool in the education system known as CBE (Computer Based Education).

• CBE involves control, delivery, and evaluation of learning.

• The computer education is rapidly increasing the graph of number of computer students.

• There are number of methods in which educational institutions can use computer to educate the students.

• It is used to prepare a database about performance of a student and analysis is carried out on this basis.

Engineering Design

Computers are widely used in engineering purpose. One of major areas is CAD (Computer aided design). That provides creation and modification of images. Some fields are:

• Structural Engineering - Requires stress and strain analysis for design of Ships, Buildings, Budgets, Airplanes etc.

• Industrial Engineering - Computers deal with design, implementation and improvement of integrated systems of people, materials and equipments.

• Architectural Engineering - Computers help in planning towns, designing buildings, determining a range of buildings on a site using both 2D and 3D drawings.

Military

Computers are largely used in defense. Modern tanks, missiles, weapons etc. Military also employs computerized control systems. Some military areas where a computer has been used are:

• Missile Control

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• Military Operation and Planning

• Smart Weapons

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:

• E-mail

• Chatting

• Usenet

• FTP

• Telnet

• Video-conferencing

Government

Computers play an important role in government. Some major fields in this category are:

• Budgets

• Sales tax department

• Income tax department

• Male/Female ratio

• Computerization of voters lists

• Computerization of driving licensing system

• Computerization of PAN card

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23 Important Questions

Define Computer and explain the basic organization of computer with a neat diagram. (Block diagram of a Computer).

Explain the Characteristics of a Computer.

Explain the Generations of Computers.

Explain the Classification of computers in detail.

What are the differences between Analog and Digital Computers?