Fundamentals of computers & information system

By shefali mishra
MBA 1ST SEM
GBAMS,MZP

“ 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 .

Most 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 .

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

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.

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 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

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 ).

The first mechanical adding machine was invented by BLAISE
PASCAL in 1642 .

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 , 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 .

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
Software Hardware
Applicatio
n software
System
software
Input
device
O.S utility
Output
device
Language
translator
C.U.I . Ex ;
dos
compiler
G.U.I . Ex ; windows xp interpreter B.I.O.S
,98,07,08,2000 assembler

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 .

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 .

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 .

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 .

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 .

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 .

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 .

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 .

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 .

This 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 .
CATCH MEMORY
CPU
CACHE
MAIN
MEMORY

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

Fundamentals of computers & information system

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Fundamentals of computers & information system