Welcome

Welcome Presentation on

Computer Fundamentals

& Computer Organization

Presented By:- Sunil Verma,PGT(C.S.)

Objective of the topic-To learn the About the history of the computer.

To develop the knowledge about the basics of the computer.

To develop the knowledge about the devices.

To develop the knowledge about the hardware and software.

Contents-About ComputerData and InformationFunctioning of a computer

Input UnitCPU UnitOutput UnitMemory Unit

Hardware and SoftwareOperating systemEvolution of computers

Contents

• Generations of modern computer• Types of computers

1. Digital Computers

2. Analog Computers

3. Hybrid Computers

WHAT IS A COMPUTER ?Def. A computer is an electronic device that can perform a variety of operations in accordance with a set of instructions called program.Computer can access and process data millions of times faster than humans can.A computer can store data and information in its memory, process them and produce the desired results.Computers can do a lot of different tasks such as playing games, railway reservation, weather forecasting, error detection and controlling the flight of a aircraft etc.Computer is used essentially as a data processor. The difference between data and information is :

Data Vs. InformationData : Data in computer terminology mean raw facts and figures.

For example,’Mohan’,1977,A . Data are processed to form information.

Information : It means what we get after processing data (meaningful data).

For example, ’Mohan, whose roll number is 1977, has got grade A’ is an information as it is conveying some meaning.

This process of turning data into information is also known as information processing.

FUNCTIONING OF A COMPUTER : Certain input is needed to accomplish a task, a process is carried

out on the input to obtain the output. Every process follows this Input-Process-Output cycle (IPO cycle).

Functional Components of a Computer :1. Input Unit : It is formed by the input devices attached to the computer.Ex. Keyboard, mouse, magnetic ink character reader (MICR),

optical mark reader (OMR), optical character reader (OCR), joystick etc.

It is responsible for taking input and converting it into computer understandable form (the binary code).

Basic Structure of a computer :

Storage Devices

Computer can understand only two stages ON/OFF or High/Low voltage or the binary language that uses just two symbols : 1 for ON and 0 for OFF.

2. Central Processing Unit (CPU) : It is the control centre for a computer. It guides, directs and governs its performance. It is the brain of the computer. CPU has two components : (i) CU (Control Unit)

(ii) ALU (Arithmetic Logic Unit)

CENTRAL PROCESSING

UNIT (CPU)

INPUTUNIT

OUTPUTUNIT

MAIN MEMORY

Arithmetic Logic Unit : It performs all the four arithmetical (+,-,*,/) and some logical (<,>,<=,>=,<>) operations.

When two numbers are required to be added, these numbers are sent from memory to ALU where addition takes place and the result is put back in the memory.

For logical operation also same procedure. The result of logical operation is either TRUE or FALSE.

Control Unit : It controls and guides the interpretation, flow and manipulation of all data and information.

It sends control signals until the required operations are done properly by ALU and memory.

Another function of CU is program execution. It gets program instructions from memory and executes them one after the other.

After getting the instructions from memory in CU, the instruction is decoded and interpreted. Then the asked operation is carried out.

After the work of this instruction is completed, control unit sends signal to memory to send the next instruction in sequence to CU.

It also control the flow of data from input devices to memory and from memory to output devices.

Output Unit : It is formed by the output devices attached to the computer. The o/p coming from the CPU is in the form of electronic binary signals

which needs conversion in some form which can be easily understood by human beings. i.e. characters, graphical or audio visual.

This function of conversion is performed by output units. Example. VDU (Visual Display Unit), printer, plotter, speech

synthesizer and coder etc. The Memory : Def : A memory cell may be defined as a device which can store a

symbol selected from a set of symbols. Each of these cells is further broken down into smaller parts known as

bits. A bit means a binary digit. i.e., either 0 or 1. A bit is an element unit of the memory.

Bit cell 0 cell 1

0 1 0 0 0 1 1 0

Def. A group of 8 bits is called a byte and a group of 4 bits is called a nibble.

One byte is the smallest unit which can represent a data item or a character.

One KB(Kilobyte) -> 2¹º -> 1024 bytes.One MB(Megabyte) -> 2¹º KB -> 1024 x 1024 bytes.One GB(Gigabyte) -> 2¹º MB -> 1024 x 1024 x 1024 bytes.One TB(Terabyte) -> 2¹º GB -> 1024 x 1024 x 1024 x 1024 bytes.Two types of memory : (i) Volatile - > Primary Memory

(ii) Non Volatile -> Secondary Memory

Hardware and Software :Hardware : It represent the physical and tangible components

of the computer i.e., the components that can be seen and touched.

The electronic, electrical and mechanical equipment that makes up a computer is called hardware.

Example. Input devices, Output Devices, CPU, floppy disk, hard disk, etc.

Peripherals : Def. Peripherals are the devices that surround the system

unit. E.g., the keyboard, mouse, speakers, printers, monitors etc.

A computer consists of five primary hardware components :(i) input devices(ii) CPU(iii) memory(iv) output devices(v) storage devices

Software : It represent the set of programs that govern the operation of a computer system and make the hardware run.

Three types :(i) Operating System(ii) Language Processor(iii) Application Software

(i) Operating System :Def. An operating system is a program which acts as an interface

between a user and the hardware.

We pass our orders/requests to operating system and ‘the Operating System’ does it for us.

OS itself decides : How to do ? ; What to do ? ; When to do ? The primary goal of an OS is to make the computer system

convenient to use and secondary goal is to use computer hardware in an efficient manner.

Major components of a computer system are :1. The Hardware2. The Operating System3. The Application Program routines (compilers, linkers, database management systems, utility programs)4. The Human ware (users)

The operating systems perform the following functions :(i) Provides the instructions to prepare user-interface(ii) Loads necessary programs (into the computer memory) which

are required for proper computer functioning.(iii) Coordinates how programs work with the CPU, keyboard,

mouse, printer and other hardware as well as with other software.

(iv) Manages the way information is stored on and retrieved from disks.

Types of OSs : single user OS, multiuser OS, batch processing OS, multiprocessing OS etc.Language Processors :-> Programmer’s language is HLL and computer does not understand it.->So it is require to convert HLL in to machine language. Software which does this is know as Language Processors.-> (i) Assembler : It converts the program written in assembly language into machine language.-> (ii) Interpreter : It converts a HLL program into machine language by converting and executing it line by line. If there is any error in any line, it reports it at the same time and program execution can not resume until the error is rectified.

User

Application Software

Operating System

CPU

User Interacts withApplication Software Interacts withOperating System Interacts with CPU and Hardware

Interpreter must always be present in the memory.For error debugging, interpreter is very much useful as it

reports the error (s) at the same time.

(iii) Compiler : It converts the entire HLL program in one go, and reports all the

errors of the program along with the line numbers.After all the errors are removed, the program is recompiled, and

after that the compiler is not needed in the memory as the object program is available.

Therefore, if we combine interpreter and compiler, it gives the best combination for HLL program translation into object code.

Application Software : Def. An application software is the set of programs necessary to

carry out operations for a specified application. These are the programs written by programmers to enable

computer to perform a specific task such as inventory control, medical accounting, financial accounting, result preparetion, railway reservation, billing etc.

Application software can be subdivided into two catergories :

1. Customized Application Software : This type of software is tailor-made software according to a

user’s requirements. The software is developed to meet all the requirements specified by the user.

Software may not fit in the requirements of the new user.

2. General Application Software : This type of software is developed keeping in mind the

general requirements for carrying out a specific task. Many users can use it simultaneously as it fulfills the general

requirements.

Strengths and Weakness of a Computer :Strengths :1. Speed2. High Storage Capacity3. Accuracy4. Reliability5. Versatility

Limitations :1. Lack of Decision Making Power2. IQ Zero

Firmware : Firmware is a prewritten program that is permanently stored

in read-only memory. It configures the computer and is not easily modifiable by the user.

Example : BIOS ( Basic Input Output Services) instructions.

Live ware : It is the term used for the people associated with and

benefited from the computer system.

FAQ-A data is a collection of-1. Raw facts2. Processing3. Transformations4. None of theseWhich of the following are software and hardware?1. Transistor2. FORTON3. Compiler

4. Integrated Circuit

FAQ-Who invented the punched card?1. Charles Babbage2. Herman Hollerith3. Both 1 and 24. None of theseDefine each of the following-1. Nibble2. Byte3. Kilobyte4. Megabyte5. Gigabyte6. Tetra byte

FAQ-Which of the following does not represent an I/O device?1. Speaker which beeps2. Plotter3. Joystick4. ALUStorage of 1 KB means the following number of bytes-1. 10002. 9643. 10244. 1064

EVOLUTION OF COMPUTERS :

Abacus : Around 3000 years before the birth of Jesus Christ, the

Mesopotamians quite unknowingly laid the foundation of the

computer era. They discovered the earliest form of a bead-and-wire counting machine, which subsequently came to be

known as abacus.

An abacus consists of beads divided into two parts which are movable on the rods of the two parts. Addition and multiplication etc. of numbers is done by using the place value of the digits of the numbers and position of beads in the abacus.

Napier’s ‘Logs’ and ‘Bones’ : John Napier (1550-1617) developed the idea of Logarithm. He used ‘logs’

to transform multiplication problem to addition problem. Pascal’s Adding Machine : Blaise Pascal, a French mathematician, invented a machine in 1642 made

up of gears which was used for adding numbers quickly. This machine was named as Adding Machine ( Pascaline ) and was capable of addition and subtraction.

The adding machine consisted of numbered toothed wheels having unique position values. The rotation of wheels controlled the addition and subtraction operations.

Leibnitz’s Calculator : Gottfried Leibnitz, a German

Mathematician, improved an adding machine and constructed a new machine in 1671 that was able to perform multiplication and division as well. This machine performed multiplication through repeated addition of numbers.

Leibnitz’z machine used stepped cylinder each with nine teeth of varying lengths instead of wheels as was used by Pascal.

Jacquard’s Loom : Joseph Jacquard manufactured punched cards at the end of

American revolution and used them to control looms in 1801. Thus the entire control weaving process was automatic.

The entire operation was under a program’s control.

Babbage’s Difference Engine : Charles Babbage. A professor of

mathematics, developed a machine called Difference Engine in the year 1822.

This machine was expected to calculate logarithmic tables to a high degree of precision. It was made to calculate various mathematical functions.

Babbage’s Analytical Engine :This engine was capable of performing all four arithmetic

operations as well as comparison.

He included the concept of central processor, storage area, memory and input - output devices in his design. The two revolutionary innovations incorporated in Anaytical Engine were comparisons and modification of stored information.Charles Babbage known as the ‘Father of Modern Computers’.Hollerith’s Machine : In 1887,an American named Herman Hollerith

fabricated the first electromechanical punched card tabu lator that used punched cards for input, output and instructions. This machine was used by American Department of Census to compile their 1880 census data and were able to complete

compilation in 3 years which earlier used to take around 10 years.

Mark-I : Prof. Howard Aiken in U.S.A.

constructed in 1943 an

electromechanical computer named Mark-I which could multiply two 10-digit number in 5

seconds. It was the first machine which could perform according to pre programmed instructions automatically without any manual interference.This was the first operational general purpose computer.

GENERATIONS OF MODERN COMPUTER : First Generation Computers(1949-55) : It used thermionic valves (vacuum tubes) and machine language was

used for giving instructions. It used the concept of stored program.Large in sizeProgramming was difficult task.Examples :

1. ENIAC : (Electronic Numerical Integrator And Calculator) First electronic computer developed in 1946 by a team lead by

Prof.Eckert and Mauchly at the University of Pennsylvania in U.S.A.

Used high speed vacuum tube switching devices Very small memory Used for calculating the trajectories of missiles. Took 200 micro sec for addition and 2800 micro sec for

multiplication. 30x50 feet long, 30 tons weight, 18000 vacuum tubes, 70000

resistors, 10000 capacitors, 6000 switches, used 150000 watts of electricity and cost $400000.

2. EDVAC : (Electronic Discrete Variable Automatic Computer) Binary arithmetic was used in construction Completed in 1950 Concept of stored program was used Operation became faster since the computer could rapidly access

both the program and data.3. EDSAC : (Electronic Delay Storage Automatic Computer) Developed by Prof. M. V. Wilkes at Cambridge University in 1949

Used mercury delayed lines for storage Concept of stored program used This allowed easy implementation of program loops.

4. UNIVEC – I : (Universal Automatic Computer – I) Commercial production of stored program electronic

computers Built by Univac division of Remington Rand and

delivered in 1951.Limitations of First Gen. Computers :Slow operating SpeedRestricted computing capacityHigh power consumptionShort mean time between failuresVery large space requirementsLimited programming capabilities

Second Generation Computers (1956-65) Invention of transistors in 1946, which were highly

reliable compared to vacuum tubes, less space and required only 1/10 of the power required by tubes.

Took 1/10 time (switching from 0 to 1 and 1 to 0) needed by tubes and were ten times cheaper than those using tubes

Invention of magnetic cores which were used to construct large random access memories.

These are tiny ferrite rings (0.02 inch dia.) that can be magnetised in either clockwise or anti-clock wise direction. The two directions represent 0 and 1.

Used transistors in place of vacuum tubes and development of magnetic disk storage devices made these computers more reliable

HLL like FORTRAN, COBOL, Algol and Snobol etc. developed

Operating Systems came in to existence Commercial applications rapidly developed

Model Size Area of Applicatio

IBM 1401 Small to Medium Business

IBM 1620 Small Scientific

IBM 7094 Large Scientific & Business

CDC 1604 Medium to Large Scientific

CDC 3600 Large Scientific

RCA 501 Medium Business

UNIVAC 1108 Large Scientific & Business

Some second generation computers :

Third Generation Computers (1966-1975)Replaced transistors with Integrated Circuits which was inverted by Jack Kilby at Texas Instruments in 1958.A single I.C. has many transistors, resistors and capacitors along with the associated circuitry encapsulated in a small package with many leads.

In Small Scale Integrated (SSI) circuits about 10 transistors per chip used

Medium Scale Integrated (MSI) circuits developed with 100 transistors per chip

Size of main memories reached about 4 MB. Highly reliable Relatively inexpensive Faster Examples : IBM-360 Series, ICL-1900 series, IBM-370/168,

ICL-2900, Honeywell Model 316, Honeywell-6000 series.

Fourth Generation Computers (1976- present) Development of Large and Very Large Scale

Integrated(VLSI) circuits packing about 50000 transistors in a chip.

Semiconductor memories replaced magnetic core memories

Emergence of the microprocessor (CPU on a single chip) led to the emergence of extremely powerful personal computers.

Costs of computers came down rapidly Speed of microprocessors, size of memory and Hard

Disk increased Use of RISC (Reduced Instruction Set Computers) For larger disks RAID technology (Redundant Array of

Inexpensive Disks) used CDROMs becoming popular, which can store info. Upto

650 MBs.Fifth Generation Computers (Coming Generation) Based on artificial intellegence, are still in

development Voice recognition is being used today Parallel processing and semiconductors are used in

fifth gen. computers. The goal of fifth generation computing is to develop

devices that respond to natural language input and are capable of learning and self organization.

Characteristic : Ability to apply previously gained knowledge, draw conclusion and then execute a task.

Computers will have to be able to classify information, search large database rapidly, plan, apply the rules which humans regard as clear thinking, make decision and learn from their mistakes.

It also include speech and visual recognition as input devices.

Applications for Fifth Generation Computers : Intelligent robots Intelligent system that could control the route of a

missile and defense systems that could fend off attacks Word processors that could be controlled by means of

speech recognition Programs that could translate documents from one

language to another.

TYPES OF COMPUTERSThe computers have been classified into three categories.1. Digital Computers 2. Analog Computers 3. Hybrid

ComputersCOMPUTERS

Digital Analog Hybrid

Purpose-Wise Size and Performance Wise

Special Purpose General Purpose Embedded Micro Mini Mainframes Super

Programmable Laptop Workstations

Digital Computers :The digital computers work upon discontinuous data. They

convert the data into digits (0 and 1) and all operations are carried out on these digits at extremely fast rates.

Digital computers are much faster than analog computers and far more accurate.

Used for business and scientific applicationsClassification of Digital computers in two ways :

(i) Purpose wise Digital Computers : Classified in to two ways

1. Special-purpose Computer : It is designed to perform a specific task.

-> The instructions to carry out task are permanently stored in the machine.

-> Computers are not versatile.

2. General Purpose Computer : It can work on different types of programs input to it and so used in countless applications.

-> Programs are not permanentaly stored but are input at the time of execution.

-> Computers are versatile.(ii) Size and performance wise Digital Computers :Classified

in to following types

1. Embedded Computers : Exist in a wide range of sizes and power.

-> The smallest are embedded within the circuitry of appliances, such as televisions, washing machines and wrist watches.

-> Programmed for a specific task.2. Microcomputers : It is a computer whose CPU is a

microprocessor.

-> Microprocessor is a processor whose all components are on a single integrated – circuit chip.

-> Normally used in offices, homes, schools, shops, stores etc.

Three categories of Microcomputers :

Three categories of microcomputers :(i) PDAs (Personal Digital Assistants) :Programmable computersVary in their power, speed, memory, and physical size.Smallest of these computers can be held in one hand.Used as notepads, scheduling systems, and address

booksThey can connect to worldwide computer networks if

equipped with a cellular phone.

(ii) Laptop (Notebook) Computers and Desktop Personal Computers (PCs) :

Used in business and at home to communicate on computer networks,

for word processing to track finances,play gamesLarge amounts of internal memoryEquipped with kb, mouse, track ball, monitor or LCD

Laptop have similar h/w and s/w as PCs, but they are more compact and have flat, lightweight LCDs instead of video display monitors.

Laptop computers are so called as they can sit on a Lap and Desktop computers are so called as they can sit on a desk.

(iii) Workstations : Similar to PCs but have greater memory and more

extensive mathematical abilities Connected to other workstations t or PC to exchange

data. Found in scientific, industrial and business

environments that require high levels of computational abilities.

3. Minicomputers : Also called mid range servers More powerful than micro computers in terms of

processing power and capabilities. Multiuser system (Multi users can work simultaneously)

Greater storage capacity and larger memories comparedto micro comp.

Capable of handling more i/p and o/p devices.Examples : PDP-11, VAX, 7500 MAGNUM etc.

4. Mainframe Computers :Designed to handle huge volumes of data and

information.Can support more than 100 users at same timeLarge and expensiveGreat processing speeds and very large storage

capacity and memory as compared to mini comp.Possess and work with more than one processor at the

same timeVery sophisticated operating systems are needed to

control and supervise their operations.Examples : ICL 39, CDC 6600, VAX 8842, IBM

3090/600, IBM 4381

5. Super Computers :Most powerful among the digital computersConsist of several processors running together, so very

powerful and fasterCapable of handling huge amounts of calculations It can perform billions of instructions per secondToday’s some super computers have the computing

capability equal to that of 40,000 micro computersThese computers cost in 15-20 million dollar range.Used for weather forecasting, nuclear science research,

aerodynamic modelling, seismology, metrology etc.Examples : CRAY X-MP-14, CDC-205, ETA GF-10,

FUJITSU VP-400, NEC SX-2, PARAM, PACE Fro general purpose applications, supercomputers do

not make the ideal choice.It can process information of only a certain kind.

Its power measured in flops (floating point operations per second)

Analog Computers :As input continuous quantities are usedComputations are carried out with physical quantities

such as voltage, length, current, temperature etc.Operate by measuring rather than countingAll calculations take place in parallel and hence are fasterAccuracy is poor as compared to digital comp.Mostly used in engg. And sci. applications.Example : An electronic weighing scale

Hybrid Computers :Utilize the best qualities of both the digital and analog

comp.Some calculations take place in analog manner and rest

of them take place in digital mannerBest used in Hospitals, also used for weather forecasting

FAQ-One mega byte is equivalent to?1. 210 bytes2. 220 bytes3. 230 bytes4. None of theseWhich of the following are parts of the CPU?1. ALU2. Memory3. CU4. Input device5. Main Memory

FAQ-Which of the following is not hardware?1. Hard Disk2. Printer3. Keyboard4. CPU5. Assembler6. Program to print table of 13Which of the following are parts of the CPU?1. ALU2. Memory3. CU4. Input device5. Main Memory

FAQ-The modern age of data processing began with the

competition of the computer?1. Analytical Engine2. ENIAC3. MARK 14. UNIVAC IA Micro processor is1. A solid state device2. Capable of performing Arithmetic operations3. Capable of performing Logical operations4. All the above

FAQ- In computer science ,by information we mean1. Any output coming out from computer2. Processed data put out from computer3. A report printed by computer4. Plural of dataThe CPU 1. Is operated from the control panel2. Is controlled by the input data entering the system3. Controls the storage unit4. Controls all input , output, processing

Thanks