UNIT- I

Basics of Computer and it’s Evolution

Evolution of Computers

• At around 600 BC ABACUS was invented which was qualified as Digital Computer

• In 1642 first mechanical adding machine was invented by Blaise Pascal

• In 1671 Barron Gottfried invented the first calculator for multiplication.

• In 1880 keyboard machines were originated in US.

• In 1890 Herman Hollerith came up with the concept of Punched card

• In 19th century Father of computer Charles Babbage came up with Analytical Computer.

• He designed “Difference Engine” in 1822

• He designed fully automatic analytical engine in 1842 for performing basic arithmetic functions.

Well known Early Computers are as follows……………………..

MARK-I COMPUTER ( 1937 – 44)• Known as Automatic Sequence

Controlled Calculator

• Fully automatic calculating machine designed by Howard A Aiken in collaboration with IBM

• Design was based on punched card machinery.

• It was complex in design and huge in size.

• Uses 3000 electrically actuated switches and was 50 ft long and 8 ft high

The Attanasoff-Berry Computer (1939-42)

• This electronic machine was developed by Dr. John attanasoff to solve mathematical equations

• It used 45 vacuum tubes for internal logic and capacitors storage

ENIAC (1943-46)• The Electronic Numerical Integrator and

Calculator was the first electronic computer.

• It was constructed by Moore School of Engineering

• It took a wall space of 20 * 40 square feet room and used 18,00 0 vacuum tubes

• Addition of 2 numbers was achieved in 200 micro seconds and multiplication in 2000 microseconds

• It was much faster in speed than Mark- I

• But—two shortcomings were:– It could store and manipulate very

limited amt of info– Its programs were wired on board

The EDVAC ( 1946-52 )

• The Electronic Discrete Variable Automatic Computer was designed on the concept of stored program concept( in which the data and instructions are stored inside the memory).

• Stored program concept was given by Von Neumann which introduced the idea of storing both instructions as well data in the binary form instead of decimal numbers

The EDSAC ( 1947 – 49)

• Britishers developed the Electronic Delay Storage automatic Calculator.

• In this machine addition operations was accomplished in 1500 microseconds and multiplication in 4000 microsecond

Manchester Mark-I(1948)

• This computer was a small experimental machine based in the stored program concept

• Designed by scientists headed by M.H.A Newman

• Its storage capacity was 32 words and each of 31binary digits

UNIVAC I (1951)

• Universal Automatic Computer was the first digital computer.

• Many UNIVAC machines were produced but first business use computer , a UNIVAC I was used by General Electric Corporation in 1954

• In 1952 IBM introduced the 701 commercial computer.

• In rapid succession, improved models of the univac-I and other 70 series machines were introduced

Generations of Computer

• Generation in computer language means – a step in technology.

• It provides a framework for the growth of computer industry.

• Originally it distinguish between hardware technologies but now it has been extended to both hardware and software which together make up the entire computer system.

• There are five generations of computer

First Generation ( 1942-1955)• We discussed about ENIAC, EDVAC, EDSAC, UNIVAC-I, and IBM-701.

• These machines were built using vacuum tubes and could perform computations in milliseconds………….were referred as First Generation Computer.

• We even saw the concept of “stored program” also emerged in this period.

• So first generation computer also worked on the principal of “Stored Program Concept” in which—DATA & INSTRUCTIONS were stored in the memory so that computer can automatically execute a program without human intervention

• Languages used were: MACHINE language

• Concept of Operating system was also not there

• So First generation computers were bulky in size, requires large room

• Vacuum tubes each vacuum tubes used half a watt of power and each computer requires more than ten thousand tubes…so power consumption was very high

• Hardware failure was very high because vacuum tubes were made up of filaments which had limited life

• COMPUTERS WERE GENERALLY USED FOR SCIENTIFIC CALCULTIONS

In brief – 1st generation

• Technology used: Vacuum tubes• Size and Speed: Huge, taking up entire room, slow

speed• Language used: Machine language• Cost: very high• Other Features:

– Used a great deal of electricity– Generated lot of heat– Inputs were based on punched cards and output was

displayed on printout

Second Generation(1955-1964)• A new electronic switching device called transistors were invented in 1947 by Bell Laboratories

which proved to be better device than vacuum tubes.

• Transistors were highly reliable and consume one-tenth of the power consumed by the tube.

• They were much smaller in size than a tube

• They were more powerful, less expensive, and cooler to operate than the first-generation computers

• Change in storage technology as the memory was made up of magnetic cores. Magnetic disk and magnetic tapes were the main storage media in second generation.

• This generation saw the emergence of Programming Languages like Assembly language FORTRAN, COBOL, ALGOL, SNOBOL and batch processing system.

• Computers was seen in business and industries for commercial data processing application

In brief – 2nd generation• Technology used: Transistors• Size and Speed: Lesser size and increased speed• Language used: Assembly language and languages like COBOL and

FORTRAN• Batch Operating system was used• Cost: cost decreased• Other Features:

– More efficient and reliable– Though transistors still generated a lot of heat that subjected the

computer to damage, but it was vast improvement over the vacuum tubes– They still relied on punched cards and output was print out

Third Generation(1964-1975)• Integrated circuits(IC) were invented.

• IC circuits consists of several electronic components like transistors, resistors and capacitors on a single silicon chip.

• Third generation was more powerful than 2nd. They were capable of performing 1 million instruction per second

• Smaller in size, less power consumption, less hardware failure

• For memory larger magnetic cores were constructed.

• So they had faster and larger primary and secondary memory

• These computers were used for both scientific and commercial applications

• Languages were high level languages like FORTRAN IV AND COBOL 68

In brief – 3rd generation

• Technology used: Integrated circuits

• Size and Speed: size lesser and speed further increased

• Language used: Time sharing Operating system was used

• Cost: reduced very much

• Other Features:

– Instead of punched cards users interacted with computers using keyboards and monitors and

interfaced with Operating system which allowed the device to run many different application

to run at a time.

• Computers for the first time became available to mass audience because they were

smaller and cheaper than the predecessor.

4th generation ( 1975 – 1989)

• Technology used: Microprocessor

• Size and Speed: reduced size and tremendous speed

• Language used: high level language ( like C, C++ etc)

• Cost: reduced cost

• Other Features:

– Microprocessor moved the realm of desktop computers.

– As these small computers were powerful they could linked with other computers

to form the network and eventually led to the development of internet.

– Fourth gen also the development of mouse, GUI’s and handheld devices

Fifth Generation ( 1990 – till today)

• Technology used: Microprocessor

• Size and Speed: reduced size and tremendous speed

• Language used: high level language, based on Artificial intelligence

• Cost: reduced cost

– Portable

– Powerful

– Cheaper

DATA, INFORMATION, KNOWLEDGE, INSTRUCTION

• Yes, Yes, No, Yes, No, Yes, No, Yes• 42, 63, 96, 74, 56, 86• 111192, 11234

What do you understand by …….

• None of the above data sets have any meaning until they are given a CONTEXT and PROCESSED into a useable form

• Let us see how data can be processed and give it a meaningful information

Yes, Yes, No, Yes, No, Yes, No, Yes, No, Yes, Yes

Example 1

Raw Data

ContextResponses to the market

research question – “Would you buy brand x at price y?”

Information ???

Processing

42, 63, 96, 74, 56, 86

Example 2

Raw Data

Context

Information

Maya’s scores in the six modules

???

Processing

111192, 11234

Example 3

Raw Data

Context

Information

The previous and current readings of a customer’s gas

meter

???

Processing

• Using the 3 previous examples:– A Marketing Manager could use this information to decide

whether or not to raise or lower price y

– Maya’s teacher could analyse the results to determine whether Maya have to repeat the module or not.

– Looking at the pattern of the customer’s previous gas bills may identify that the figure is abnormally low and they are fiddling the gas meter!!!

Knowledge Examples

• Data are raw facts and figures that on their own have no meaning

• These can be any alphanumeric characters i.e. text, numbers, symbols

WHAT IS DATA

• Data that has been processed within a context to give it meaning

OR• Data that has been processed into a form that gives it

meaning

WHAT IS INFORMATION

Summary

Information Data Context Meaning= ++

ProcessingData – raw facts and figures

Information – data that has been processed (in a context) to give it meaning

WHAT IS KNOWLEDGE

“…the capability of understanding the relationship between pieces of information and what to actually do with the information”

Knowledge

Information

Data

What is Instruction

• An instruction is an order given to a computer processor by a computer program.

WHAT IS Computer???

• A programmable machine which responds to a specific set of instructions in a well defined manner.

All computers requires following hardware components

• CPU: heart of the computer that actually executes instructions• Memory: enables a computer to store the data and program• Input device: means through the data and instructions enters

into the computer• Output device: A display screen that lets you see what the

computer has accomplished

Characteristics of Computer

Automatic

• A machine is said to be automatic if it works by itself without human intervention.

• Computers are automatic because once started a job they can carry on until the job is finished.

• They only have to be instructed

Speed

• A computer is very high speed device.

• Computer speed is given in terms of seconds i.e. 10-3 means milliseconds

• 10-6 means microseconds• 10-9 means nanoseconds• 10-12 means picoseconds

Accuracy

• Computers are accurate• Degree of accuracy of a computer depends upon its

design

• If the input data is correct and the program instructions are reliable then computer will produce the accurate result

• Wrong input produces wrong output which is known as Garbage in Garbage OUT

Storage

• Computers are capable of storing huge amount of data and instructions.

• Computers have main memory and auxiliary memory.

• The factor that makes computer storage unique is not that it can store vast amount of data but the fact that it can retrieve the information that the user wants in few seconds

Diligence

• Unlike human beings, a computer is free from monotony and tiredness, lack of concentration and \hence can work for hours without creating error and without grumbling

• If ten million calculations have to be performed, a computer will perform with the ten millionth calculation with the same accuracy and speed as the first one.

Versatility

• They can perform activity ranging from simple calculations to complex Cad modeling and simulation to navigate missiles and satellites

• In other words they are capable of performing almost any tasks provided task can be reduced to a series of logical steps which can be coded

• Computers can communicate with other computers( internet, WWW)

But…………

• They don’t have I.Q.• They don’t have feelings

Fourth Generation(1975-1989)• They used the VLSI( very large scale integration technology) which can integrate over

30,000 electronic components on a single chip. The progress led to the dramatic development of Microprocessor.

• Microprocessor contains all the circuits needed to perform the arithmetic, logic and control function, the core activities of the computer on a single chip.

• Hence the personal computer revolution started.

• PCs were much smaller and cheaper

• Power consumption was very low

• Larger and faster memory.

• Graphical user interface

APPLICATION OF COMPUTER IN VARIOUS FIELDS

Use of computer in different fields

• Business.• Medical.• Banking sector.• Education.• Service sector.• Defence.• Engineering and Robotics.• Entertainment.

BUSINESS

• MARKETING :- Computer is mainly used for sales promotion, e.g. designing of advertisements.

Internet marketing (e-marketing).

Comparing the sales figure.

Studying the demand graph.

• PRODUCTION :-It is used for making design of product.

CAD (computer aided design)

CONTD….

• HUMAN RESOURCE :- Computer is used in keeping the records of all the employees.

Recruitment and Selection.

• FINANCE :- Helps in making the financial statement.

Comparing the financial statement of two year.

Preparing the “BUDGETS”.

MEDICAL

• Research :-Used in different pharmaceutical companies.

• Hospitals :- Mainly computer is used for keeping the record of patients.

Inventory of medicines. Surgeries.

• Diagnosis :- CT scan. Ultra-sound. Blood test. Electro-cardio gram.

BANKING SECTOR

• Maintaining the record and storing the files instead of manual record.

• Internet banking (e-banking).• Transaction from ATMs.• Bank sell their insurance online.• Bank provides 24×7 online services.

EDUCATION

• Higher education :- All the universities and colleges are furnished with computer labs.

• Online education :- This can done with the help of computer and internet.

• Self-Learning. • Faculty usage.• School library.• Used to generate letters and documents.

SERVICE SECTOR

• Railways :- Computerized reservation and cancellation is done.

• Online reservation, Schedule, Availability and fare, Position of the train

• Transportation.• Airways• Hotels.

DEFENCE

• Air force :- All the fighter plane are equipped with computer system for targeting and navigation.

With the help of computer only “PREDATOR” an unmanned fighter can be controlled.

• Army :- Gentle men uses computerized “ROBOT” in the battle field. Tanks are also installed with computer.

• Navy :- Today all the submarines uses computer far navigation and targeting.

ENGINEERING AND ROBOTICS

• Software.• Design of buildings and maps.• Designing VLSI chip and many more.• Robotics research.

ENTERTAINMENT

• Chatting /browsing.• Music/Videos• Games etc..

Input-output Devices (Hardware, Software, Humanware and

Firmware)

• A computer system is a combination of various components.

• It performs the system functions such as input, processing, output, storage and control.

• A computer system consists of the following components:

• Hardware• Software• Human ware• Firmware

Hardware

• The physical components of the computer, such as electrical, electronics and

mechanical unit are known as the hardware of the computer.

• The input units, output units and CPU are called hardware.

• Hardware consists of the components that can be physically handled.

• The function of these components is typically divided into three main categories: input,

output, and storage.

• Components in these categories connect to microprocessors, output and storage.

• Components in these categories connect to microprocessors, specifically, the

computer's central processing unit (CPU), the electronic circuitry that provides the

computational ability and control of the computer, via wires or circuitry called a bus.

Software

• The computer performs operations like addition, subtraction, multiplication and division only when the user instructs it to do so. The user issues instructions and the CPU acts in accordance with the instructions. The sets of instructions, which control the sequence of operations, are known as programs, and collectively programs are called software. The software can be broadly classified into two types.

• They are:– System Software– Application software

Human ware

• The man-machine interface is called a human ware. The people who work with the computer are collectively called the human ware or livewire

Firmware

• The computer programs permanently stored in ROM or PROM are called firmware.

• These programs are provided by hardware manufacturer along with the computers.

• Generally these are booting programs which help in the starting of a computer. Such programs cannot be erased or overwritten.

• HARDWARE– Hardware refers to physical components that can be seen and

touched. Eg: CPU, memory, I/O devices• SOFTWARE

– Software is the set of the programs that make the hardware of the computer run.

– Program is a set of instructions• FIRMWARE

– Firmware is like a prewritten program that is permanently stored in the read only memory.

– BIOS( basic input output services) is the example of firmware

• LIVEWARE– It is the term generally used for the people associated with and

benefitted from the computer system.

BLOCK DIAGRAM OF COMPUTER

Input Unit Output Unit

Secondary Storage

Arithmetic Logic Unit

Control Unit

Primary storage

Program and Data

Information

Storage Unit

CPU

Flow of instruction & data

Control exercised by the control unit

• THERE ARE FIVE MAJOR BUILDING BLOCKS OF COMPUTER

• These five units corresponds to the five basic operations performed by all computer systems

Input Unit• Data and instruction must enter in the computer before any computation is performed.

• This task i.e. inputting is performed by the input unit that links the external environment with the computer system.

• Data and instructions which enters inside the computer system depends upon the particular device used like data enters from keyboard differs from data entered from scanner.

• Once the data enters it is transformed into binary codes which is accepted by the primary memory of computer.

• This transformation is done by Input interface.

• In Brief

– Input unit accepts the instruction and data from outside world

– Convert these instructions and data into computer acceptable form

– Supplies the converted instructions and data to the computer system for further processing

Output Unit

• Job of output unit is just the reverse of input unit.

• It supplies the information obtained as a result of data processing to the outside world.

• Result produced by the computer is in binary form therefore the output interfaces transform these binary codes into human readable form.

• Thereby supplying these converted result to the outside world.

Storage Unit• The data and instruction that are entered in the computer system have to stored

before the actual processing starts.

• Also the result produced by the computer after processing must be kept somewhere inside the computer system before passing on to the output unit.

• Again the intermediate result also need to be preserved for the ongoing processing.

• Storage unit is capable of satisfying all these needs.

• So storage unit stores:– ALL THE DATA AND INTRUCTIONS TO BE PROCESSED– INTERMEDIATE PROCESSING RESULT– FINAL RESULTS OF PROCESSING

Storage contd….Storage unit comprises of two types of storage

• Primary Storage/Main memory:– It holds the pieces of programs and instructions that the computer system is

working on. – These information which are present in the main memory can be directly

accessed by the CPU at a very fast speed.– It can store information only till the computer is on.– As soon as the computer if off it loses the data stored– Primary storage is limited in capacity– It is very expensive

• Secondary Storage/Auxiliary memory– It is used to supplement the limited storage volatile characteristics of primary

storage.– It stores the program, data and information of those permanently.– Data stored in this memory will not be lost even if the computer is switched off.

Central Processing Unit

• Control unit and ALU are jointly known as the CPU.

• It the brain of the computer

• All major calculations and comparisons are made by the CPU.

• CPU is responsible for activating and controlling the operations of other units of a computer system

Arithmetic Logic Unit• It is the place where the actual execution of the instruction takes

place during the processing.• All the calculation and decisions are made in the ALU.

• Data and instructions are transferred to the ALU for the processing.

• Processed information are then transferred to the primary storage.

• Therefore data moves from primary storage to LAU and vice-versa

• After completion data is transferred to the Output unit

Control Unit• How does the input device know that there is a time to feed data in the computer

• How does the ALU knows what to be done with the data they received?

• How the final result are sent to the output device?

• By selecting, interpreting, and seeing to the execution of the program, the control unit is able to maintain the order and direct operation of the entire system

• Although it does not perform any actual processing.

• But it acts as the nervous system of computer

• It manages and coordinates the entire computer system.

• It obtains instruction from the stored program in main memory , interprets and issues signals that causes other unit to execute them

CLASSIFICATION OF COMPUTERS

1. On the basis of Technology2. On the basis of purpose

Classification of Computer on the basis of technology

• Analog Computers• Digital Computers• Hybrid Computers

Analog computers• 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.

Examples: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. Weight machine and Speedo meter are other examples of analog computers.

Characteristics of the analog computers

• These computers have no state• The Speed of analog computer is fast• These computers are not reliable• These computers became the base for digital

computers• These computers are difficult to operate and use• These computers are easy to develop• These computers have small memory

Digital Computers

• The computers which present physical quantities with the help of symbols or numbers and provide us discrete information are called digital computers

• Examples:Digital watch, digital petrol stations and the computer, which we use nowadays, are the examples of digital computers

Characteristics of the digital computers

• Digital computers have two states On (0) and Off (1).• These computers are easy to use.• Human being like to use digital computers.• These computers are reliable.• Digital computers have big memory.• Working speed of digital computers is slower as

compared to analog computers.• These computers are further divided into different

categories such as personal computers, Mainframe computers and super computers.

Hybrid Computers• The computers which have qualities of both digital and analog

computers are called hybrid computers

• Hybrid computer has the speed of analog and the accuracy of digital computer.

• Example:In ICU (Intensive care unit) of a hospital hybrid computers are used. These computers analog quality controls the temperature of the room digital quality informs the doctor about the blood pressure, temperature and physical status of the patient.In Cement factory a hybrid computer is used where all calculations are performed by the digital computers; and actions like increase of material are performed by the analog computers

Characteristics of the Hybrid computer

• These computers are reliable and provide accurate result

• These computers are fast and speedy.

Classification of computers on the basis of Purpose

General Purpose Computer• General-purpose computers are designed

to solve a large variety of problems. That is they can be given different programmes to solve different types of problems

• General-purpose computers can process business data as readily as they process complex mathematical formulas.

• General-purpose computers can store large amount of data and the programmes necessary to process them.

• Because general-purpose computers are so versatile, most businesses today use them.

• Most digital computers are general computers and it is mainly such computers that are used in business and commercial data processing.

Special purpose computer• Special purpose computers are

designed to solve a specific problems

• The computer programme for solving the problem is built right into the computer.

• Special purpose computers have many features of general-purpose computers but are designed to handle specific problems and are not applied to other computerized activities.

• Ex: – Controlling the temperature and

humidity– Monitoring your heart beat– Monitoring your house security system

Types of Computer• Personal Computer: A small, single user computer based on microprocessor.

• Workstation: A powerful single user computer which is like personal computer but requires a powerful microprocessor and a high quality monitor

• Minicomputer: A multi-user computer capable of handling10 to hundred users simultaneously

• Mainframe: A multi-user computer capable of handling hundreds of user simultaneously

• Supercomputer: an extremely fast computer which is capable of executing hundreds of millions of instruction per second

Number system

Importance of Hexadecimal and Octal numbers system for a computer system

• The study of number systems is useful to the student of computing due to the fact that number systems other than the familiar decimal (base 10) number system are used in the computer field.

• Digital computers internally use the binary (base 2) number system to represent data and perform arithmetic calculations. The binary number system is very efficient for computers, but not for humans. Representing even relatively small numbers with the binary system requires working with long strings of ones and zeroes.

• The hexadecimal (base 16) number system provides us with a shorthand method of working with binary numbers. One digit in hex corresponds to four binary digits (bits), so the internal representation of one byte can be represented either by eight binary digits or two hexadecimal digits.

• Octal (base 8) number system is used, where one digit in octal corresponds to three binary digits (bits).

• In the event that a computer user needs to examine a display of the internal representation of computer data, viewing the data in a "shorthand" representation (such as hex or octal) is less tedious than viewing the data in binary representation.