Fundamentals of computers & information system

By shefali mishraMBA 1ST SEM GBAMS,MZP

UNIT - I

Computer

“ It is a high speed electronic device which is capable of performing logical and arithmetical operations . It accepts data as an input from the user, processes and gives desirable output ”

DATA : They are a set of related facts, the new material of information, data represented by symbols, but they are not information accept in limited sense .

Information : The analyzed data details is termed as information . As used in data processing, information is data arranged in an order and form that is useful for people who receive .

Features of computerMost of people know that a computer is fast calculator . But it is much more than that ,

some of features that make a computer so important are its :-

I. Speed :- The first feature of computer is speed . It is a very fast device which can perform any type of task in fraction of seconds. When performing a particular task for hours together . it can maintain the same speed till the end of it .

II. Accuracy :- The word accuracy means exactness of result . The accuracy with which a computer perform calculation or processes data is very high . It never gives wrong information unless user does .

III. Storage :- One of the most important features of computer is storage . A computer can store large amount of data and whenever required can retrieve it back very easily.

IV. Versatility :- A computer can perform almost all type of arithmetical and logical operations .

V. Automation :- A computer can perform a particular work continuous for hours together without any user ( human ) intervention .

VI. Diligence :- A computer does not suffer from human trait or tiredness or board . If 3 million calculation has to be performed , it will perform the 3rd millionth calculation with the same speed and accuracy as the first one .

Block diagram of computer

Input unit

Output unit

memory unit

ALU

Control unit

DATA FLOW

(Viz ; keyboard , mouse , Iight pen , etc . )

(Viz; monitor , printer etc)

C.P.U

CELL

Units of computer INPUT UNIT SYSTEM UNIT OUTPUT UNIT

1. Input unit :- it is a device which is used in transferring the data or instruction to the computer system . Most commonly used input device are keyboard , mouse , card reader, magnetic disk .

2. System unit :- it is regarded as the brain of the computer . The major structural components of C.P.U. are –

(a) control unit(b) Arithmetical and logical operation(c) Memory unit

(a) control unit :- Control unit device directs and coordinates the activities of the entire computer which includes controlling the input/output devices or units ,the operation of ALU and the transfer data to main memory . An important function of C.U is program execution , fetching an instruction from memory , decoding it and sending it to an appropriate place in the computer to get it executed .

(b) Arithmetic logic unit(A.L.U) :- The arithmetic logical operation unit performs

arithmetic operation, the operands are brought to ALU from the memory . In ALU the required operation is done and the result is sent back to memory for storage ALU . All these happens under the control unit . ALU also perform comparison which are called logical operation, these occurs when the operation are connected with logical operation .

LOGICAL OPERATION SYMBOL

EQUAL TO =LESS THAN <GREATOR THAN > (c ) Memory unit :- The data and instructions that are entered into the system has

to be stored inside the computer before the actual processing takes place . Similarly the final results produced by the computer also has to be stored before they are passed to the output units .

3. Output unit :- The data passed through the C.P.U can be viewed with the help of output device ,the monitor or (VDU) of a PC is an output device.

History of computer

The discovery of numbers, which is considered as the greatest achievement of mankind led to the development of all kinds of calculating device . Today we can’t imagine a work without numbers , it took thousands of years to get the present system of numbers .

The stone age man used pebbles for counting people or animals , stone was replaced by sticks on the rope .

THE ABACUS

The earliest and the simplest device that was used for calculations was the ABACUS , simple abacus has been in use since 3000 B.C.

Abacus was first developed in china and later its use spread to all parts of the world .

clay

board

beads

wire

ABACUS

Napier’s “logs” and “bones”

The next manual calculating device logarithms was invented by john Napier . The use of logarithms enabled him to transform multiplication and division problems of addition and subtraction . The word logarithms is a combination of two Greek words , logos (means ratio) and arithms (means numbers ).

Pascal adding machineThe first mechanical adding machine was invented by

BLAISE PASCAL in 1642 .

Jacquard’s loom Joseph jacquard

initiated actual development in the early 19th century . Jacquard was a textile manufacturer he invented automated loom in 1804 . He used punched card to produce complex cloth pattern with automated loom .

Charles Babbage Charles Babbage , a

nineteenth century professor at Cambridge university is considered to be father of modern digital computer . He designed his “different engine” in 1822 and his “analytical engine” in 1833 .

Hollerith’s machine In 1855 , Herman

Hollerith , developed a machine run on the electricity for the first time for calculating and recording data . It was capable of reading both numbers and letters , processing and giving out letters and numbers in designed form .

Computer chart

computer

Software Hardware

Application software

System software

O.S utility

Input device

Output device

Language translator

C.U.I . Ex ; dos compil

er interpreter

B.I.O.S

G.U.I . Ex ; windows xp ,98,07,08,2000 assemble

r

Important terms :1. Computer: It is an high speed electronic device which is capable of performing

logical and arithmetical operation .

2. Software : It is set or series of instruction given by user is known as program , the instruction is written in one of many language when the computer can understand and are called the programming language . All the computer programs written in any programming language are collectively known as software .

3. System Software : It is a collection of programs designed to operate , control and extend the processing capabilities of computer . It can be classified further into three parts .

Language translator :- A software that convert source codes into machine case vice-versa are called language translator .

(a) Interpreter :- It is a program written in machine level language whose function is to translate the high level program into the machine level language .

(b) Compiler :- Compiler will check the program at a time and display all the errors.

(c) Assembler :- It is a program written in assembly level language whose function is to translate the assembly level program into the machine level program ..

Operating system :- A collection of programs and utilities that provide a basic working environment for other software application and computer user . It provide a platform where all the application software runs .

EX : MS-DOS , UNIX , WINDOWS , etc .

Classification of operating system .

(a) Single program/user o.s :- It permit one application or program to be run at a time , when the processor (C.P.U) of a computer does one job at a time .

(b) Multi user o.s :- It permit numbers of application of user to work at the computer at the same time . Ex : LINUX,UNIX.

(c) Graphical user interface :- It uses icons or small images to represent program features instead of typing (or) entering the command . Ex: window 95 , 98,2000 etc .

(d) virtual storage o.s :- It is originally devised , when the programs that were too large to fit in primary memory i.e. RAM . A visual storage operating system will permit data to be moved between primary & secondary as and when the primary storage proves to be too small .

Utility :- These are the programs , pre-written by the manufactures and supplied with hardware . Ex: text editor , sorting , formatting , etc .

Generations of computer

Generation of computer : The term generation refers to major development in electronic data processing . Computer technology has been aimed at making smaller cheaper and efficient computers. The development of computer has been very rapidly in last fifty years . It has been in five distinct stages . Each of these stage is called generation .

First generation (1946-1955)

The first generation computer is based on the vacuum tube technology . In the first generation some important some important computers that were designed are as follows :

ENIAC (electronic numerical and calculator ) :- In 1946, Mauchly and Eckert completed the first large scale electronic digital computer ENIAC . The ENIAC was programmed by connecting wires between units of the computer and setting switches at the 50 feet . It was used for , atomic energy calculation and random numbers studies .

EDSAC :- After ENIAC was turned off , another computer EDSAC ( electronic delay storage automatic calculator) came in 1943. EDSAC was first computer to operate on the stored program concept . It started operating only in 1951 . ENIAC, EDSAC and other computer which were developed in 1940’s were experimental basis .

UNIVAC :- UNIVAC ( universal automatic computer) was the first computer dedicated to business application . It was also used for the analysis of 1952 presidential election in united states.

Drawback : First generation computer based on vacuum tubes

created several problem It generates too much heat . It consumed lots of electricity. Its, size was large , unreliable and required

constant ,maintenance . The computer programming language was in binary

digit (0,1) which have a special meaning that can be understood by computer .

It was very difficult to write program in machine language , moreover most program contained errors and the knowledge was restricted to few people .

Second generation (1956-1965)

Major innovation was the solid state device – transistor by three scientist J.BARDEEN , H.W BRATTIAN and W.SHOCKLEY in 1947.

A transistor is made of a semi conductor material whose basic part is silicon

The size of transistor is only 1/200th of the size of vacuum tube

Require much less power and produce less heat .

Ex : IBM 7094,NCR 304, IBM 1620, ALTA’S etc .

Third generation (1966-75)

Integrated circuit technology was introduced around 1965.

It is the combination of numbers of transistors and other electronic components fused together on a single crystal.

Mass storage device were called auxiliary or secondary storage device i.e. magnetic tape , disk , etc .

Multi – programming software in which more than one can be present in computer memory simultaneously .

High level language like basic COBOL, FORTAN , etc , were developed .

A new computer industry called software industry was born .

Ex: IBM -360, ICL-1900,PDP-8, IBM-370/168 , etc .

Fourth generation (1976-1985)

A new technology Micro-processors were introduced .

A microprocessor chip (approx 1/4”*2” in size) contain an entire central processing units on single chip .

Large scale integration (L.S.I) and very large scale integration (V.L.S.I) technology were used in fourth generation .

Size and cost reduced . Desktop came into the

market .

Fifth generation (1986 onwards)

Ultra large scale technology (U.L.S.I) were introduced

Developed very small but extremely fast and powerful computers which is known as ROBOTS .

Size were very much reduced . Small in size and easy to carry out .Ex: mainframe , super computer , ROBOTS .

Input devices The device which is used to input information or instruction into the computer are

called input device . Below are given a few input devices:

KEYBOARD: Allows user to interact directly , it resembles an electronic type writer keyboard , available in two main category ;

(a) Standard with usually 83-84 keys .(b) Enhanced or extended with 101 keys . It is divided into 4 main parts .1. Main pad.2. Function key pad .3. Numeric key pad.4. Special key pad.

MICR : Magnetic ink character reader is basically used in banking industry to read Cheques .

OCR : Optical character reader is capable of reading any printed or hand written text they can read at the rate 2400.

OMR : Optical mark reader can recognize marks made by pencil or ink on specially designed paper with boxes which can be marked with a dark pencil or ink.

BCR: Bar code reader used to indentify a particular product written in bar or shops over the product , ex: books , packages etc .

MOUSE : An electro- mechanical device used as pointer to select items from an “ on screen” menu.

SCANNER : The scanner is used to scan images and store it on the disk as a file , it can be flat bed or roller feed variety .

LIGHT PEN : It is a pointing device which can be used to select an option by simply printing at it ,or draw figure directly on the screen and more figures around .

TOUCH SCREEN : Normally used when information has to be assessed with minimum effort , the screen is made sensitive to touch and exact position is detected . The screen is lined with light emitting device ( LED ) . It is used in hospitals , railways , air lines , restaurant , stock exchanges , etc .

JOYSTICK : It is mainly used with computer games , and it some times called game controller . It can be moved left and right (or) up and down as required to move the cursor .

Output device

The input received is processed in the processing unit and when the result are ready , are given inform of output . The device through which these output are given are known as output device . Below are some commonly used output devices .

MONITORS :- The most commonly used output device is the visual display unit (V.D.U ) , which is used to

display information on the screen the V.D.U. consists of a CRT ( cathode ray tube ) which produces a beam of electrons that make the picture on the screen . A VDU normally consist of 25 rows an 80 columns . It has 200 pixels from top to bottom and 640 pixels from left to right .

Popularly monitors are :

o Monochrome :- These types of monitors have single foreground colures and single background color but have various attribute . Ex; the brightness and intensity of character which can be changed .

o C.G.A ( color graphic adapter ) :- Introduce by IBM in 1982, these monitors are of low resolution screen (640 row*200 columns) with color capabilities .

o H.G.A. ( Hercules graphic adapter ) :- Introduced by Hercules computer technology in 1982 , these are monochrome adapter with additional graphic display mode which provide high resolution in graphic mode (750*350 dots )

o E.G.A. ( Enhanced graphic ) :- Introduced by I.B.M in 1984 , it was developed in an effort to unify the variety of display adapter . The E.G.A combines all of the features of other adapter an d provide high resolution using higher quality color monitor . It support 16 colors .

o V.G.A ( video graphic adapter ) :- Introduced by I.B.M in 1987 , these monitors support higher resolution and are very expensive . It can support 256 color at a time .

o Super V.G.A:- Introduced by a group of American companies in 1988 , it uses more pixels (56.1) more than V.G.A.

PRINTER :- A hardware device that produces text

or graphics output on a paper , printer are grouped broadly into either impact or non-impact

Impact printer : These printer have mechanical

contact with print medium ( usually paper ) to create an image ( Dot matrix , line printer , daisy wheel printer )

Non – impact printer : Those printer that not have direct

contact with the print medium fall under this category ( inkjet printer , laser printer ).

PLOTTER :- A printer is capable of producing output that contains printed words . It is

capable of printing straight lines and simple figure like squares , rectangles and circles . It require to create high quality visual on papers , which a printer a printer is not capable of doing . For this purpose , at plotter is used .

A plotter is a printer that is used to create presentation , charts , graphics , maps , and diagram prepared for statically application like CAD ( computer added design ) , engineering drawing etc .

Primary storageThis memory is directly associated with the C.P.U. before being actually processing the data , this is to be

stored in some storage area . This storage area is known as primary storage .It is divided into two distinct parts:-

I. RAM and ii. ROM

RAM :- Random access memory where all data will be stored , while typing anything it directly stores in electronic circuit and it works continuously till power continues . It goes through reading procedure from input device to RAM and it writes from RAM to secondary device like floppy/ hard disk.

ROM :- Read only memory basic startup routines and Bios ( basic input output system ) are permanently loaded during the manufacturing time . It can’t be altered and fresh information cannot be written into a ROM .

So, if the power is off computer does not lost it’s contents . It has three parts :

(a) PROM ( programmable read only memory ) :- Once the chip has programmed the recorded information can’t be changed .

(b) EPROM(erasable programmable read only memory) :- It can be performed or reprogrammed , usually by exposing a normally covered sector to ultra –violet light , information can be only “read” and the information remains on the chip until it is erased .

(c) EEPROM ( electronically erasable programmable ROM ) :- RAM can not store memory between power interruptions , and hard disk are slow . Enter flash memory , it does not lose it’s data even if the power is turned off . A flash memory is used in portable device such as digital camera , voices , recorders and handled computer .

Cache memory :-

These are small but fast memory logically positioned between the internal and main memory . It stores or catches some of the content of the main memory , currently in use by the processor . Being nearer to the C.P.U. than the RAM it plays a major role in the speed and performance of a processor’s (CPU). To make the processor job easier and quick , the cache memory stores anticipated instruction . The size of cache memory being very small . Whenever a CPU requires data , it checks with the cache and if available , directly uses the same . Currently PCs normally features two of cache , L1 or primary cache located in the CPU itself and L2 or secondary cache located on system ‘s motherboard .

CPU

CACHE

MAIN MEMORY

CATCH MEMORY

Secondary storage device

For permanent storage of data , secondary device can be used with a p.c. system . Secondary storage is also referred to as external storage .

(A) MAGNETIC TAPES: These storage device are used to keep back-up copies of previous software and data .

(B) FLOPPY DISK : IT was developed in 1970’s as a cheaper and faster storage device .it is small random access disk .

(c) HARD DISK : Another magnetic media suitable for strong large volume of information is the hard disk . A hard disk pack contains two or more magnetic plates fixed to a spindles one below the other with a set of read/write heads

(D) CD-ROM :- Compact disk read only memory is an optical storage medium capable of holding up to 660 MB data ( approx 500,000) range of text about 70 minute of high fidelity audio or a combination of the two .

(E) ZIP DRIVE : A zip drive , which used a removable disk cartridge , can be used for backups . It can typically stores 100 MB or move on each removable cartridge . The advantage of this device is that it is random access just like a disk drive .

(F) DVD- ROM : THE CD-ROM is going to obsolete very soon after arrival of DVD-ROM in the market for DC-users , it has several time higher speed and capacity of CD-ROM very soon . It will be counted as most common device name CD-ROM . The full form of DVD-ROM is Digital video disk read only memory .

THE END