FUNDAMENTAL OF COMPUTER
COMPUTER FUNDAMENTAL
Computer:- A computer is an electronic device which performs
arithmetical and logical tasks where arithmetical means addition, subtraction, division,
multiplication and Logical tasks means (AND, OR, NOT).
Ø It accepts
the input from the users and then processes it after that it gives the output.
Ø It is used
in the field of communication has led to wonders and has resulted in the era of
information technology, that we live in today.
Characteristics of a computer:-
There
are following characteristics of a computer such as-
Ø Speed- it works at a very high speed. It can execute
millions of instructions per second. Its speed is measured in hertz i.e.(khz,
Mhz, Ghz, etc). But modern computers can perform calculations in ‘Nano Second’.
Ø Accuracy:- computer is an accurate machine. It does not
make mistakes. It performs calculations without making errors and produces
information in accordance with the data entered.
Ø Reliability:- computer is reliable in nature. it does
not fail to produce results. It calculates exactly as per the given
instructions. It can even work in places where human beings cannot.
Ø Versatility:- computer is versatile in nature i.e. it can work on
various kinds of input and produce multiple kinds of output in the form of
sound, graphics, text, animations, etc.
Ø Storage capacity:- A computer has a very huge memory. It
can store large volumes of data in a small place, which can be retrieved as and
when required. The unit of storage is the byte.
Ø Diligence:- A computer is free from the problems of tiredness, monotony, or lack
of concentration. It can work for many hours without getting tired.
Ø Logical ability:- A computer is capable of comparing all
types of data are it numeric or non-numeric and it can even take logical
decisions as per the given instructions.
Ø Flexibility:- during its operation. a computer can
perform multiple tasks at the same time. It can instantly switch from one
application to another at any point in time during operation.
Ø Transfer of data:- Data can be easily transferred from one
computer to another computer.
Limitations
of computer:-
Ø Computer has zero IQ so it can not think on its own, it
has to be guided or instructed by the users.
Ø Computer is apathetic in nature. it means that it has no nay sentiments.
Ø It is non-heuristics in nature. it means that the computer
has artificial intelligence. It can not learn from past experiences.
CPU(Central processing unit)
Ø It is the brain of the computer.
Ø Process of data is done inside the CPU. It converts raw
data into information.
Ø It is a hardware component as it looks, but it is also
an important functional component of a computer system.
Functional components of a CPU
There are following functional components of CPU such as :
1.
MU
2.
CU
3.
ALU
Cu:- it stands for
control unit.
Ø It
co-ordinates and directs the operation of the hardware devices.
Ø It also
co-ordinates the flow and execution of the data and instructions that are fed
into the computer’s memory.
Ø CU
functions in an F-D-E-S(fetch decode execute store ) cycle.
Ø It fetches
the instruction and data from the memory unit.
Ø It decodes
the data and instruction and passes it to the ALU for further processing.
Ø It also
direct the ALU to execute the instruction and perform the required operations
on the data.
Ø It performs mathematical and logical tasks.
Ø Mathematical
task means +,-,x,/ etc and logical means >,<,>=, <=, !=..etc .
Ø It receives
the coded data and manipulates them to
produce information in machine code and then sends it to the control unit.
Ø It stores
the data, instructions, intermediate results, and final results that are ready
for output.
Ø All data
are stored in the memory unit before being used by CU and ALU.
Ø The memory
location is accessed by a unique number which is known as a memory address.
Ø Within the
CPU a high speed, special purpose memory units called registers.
Ø The control
unit and other internal storage are linked together by sets of parallel
electrical conducting lines called Buses.
Ø The buses
that carry data are called data bus.
Ø The buses
that carry address are called address bus.
Ø The buses
that carry control signals are called the control bus.
COMPUTING DEVICES
** Input device:- the device by which we input or fed the data into the computer is known as an input
device.
è Keyboard,
mouse, joystick ...etc are the example of input device.
1. Keyboard:
it is the most common input device.
è It is
mostly used to type the text and send the instruction to the computer.
è It has 101
to 106 keys.
è QWERTY, QWERTZ,
AZERTY and DVORAK are examples of a keyboard.
è QWERTY type keyboard is most common in use. It is
based on the English alphabet.
è AZERTY
type keyboard is mostly used in France.
è QWERTZ type
keyboard is widely used in Germany and central Europe.
Note: keys are
the buttons that represent numeric, alphanumeric, and special characters. In a laptop, the notebook keyboard is known as a keypad.
è It has two
button and one scroll wheel on its top.
è Its the function is similar to a mouse. It is used to playing games.
è It takes the image of contents and converts it
into digital files inside the computer.
Scanners can be categorized as a handheld scanner and Flatbed Scanner.
è It is an
input devise which is used to detect marks on the paper.
è It is used
to evaluate the OMR answer sheet.
è It is an
input device which is used to detect mark as well as its shape and identify the
character directly from the source document.
è It is used
in the verification of examination forms in different educational institutions.
è It is an
input devise which is used by banks for processing of cheques.
è It has
light-sensitive detector to select or to draw objects on the display screen.
è The quality
of the digital camera is measured in pixels.
è The common
use of web cameras is in video conferencing.
UNIT OF STORAGE:
|
No. Of
bits/bytes |
Said as |
|
4 Bit |
1 Nibble |
|
8 Bit |
1 Byte |
|
1024 Byte |
1 Kilobyte |
|
1024 Kilobyte |
1 Megabyte |
|
1024 Megabyte |
1 Gigabyte |
|
1024 Gigabyte |
1 Terabyte |
|
1024 Terabyte |
1 Petabyte |
|
1024 Petabyte |
1 Exabyte |
|
1024 Exabyte |
1 Zettabyte |
|
1024 Zetabyte |
1 Yottabyte |
|
1024 Yottabytes |
1 Brontobyte |
|
1024 Brontobyte |
1 Geobyte |
è If the computer is suddenly off then data stored in it does not get lost like
temporary memory.
è It provides
necessary backup and storage of instruction or data that can be retrieved back
whenever required. So it is also known as backup and recovery memory.
è It has
higher storage capacity than the primary memory.
è There are
various types of secondary memory such as:
1. Magnetic
Disks:- it is a storage device that is also made up of magnetic
coated material.
è The surface
of each disk is marked with invisible circular tracks. The data is stored in
the form of magnetic spots on it.
è In this
storage device data can be searched much faster than magnetic tapes.
è Hard disk
is most widely used in the computer system as internal storage.
è It is made
up of smooth metallic plates with a thin layer of magnetic material. Each plate
of the hard disk is known as a platter. And each plate has two read-write heads.
è It is also
known as Winchester disk. It has different storage capacity like 500mb, 1 Gb,
1Tb.... etc.
è There are
so many optical Memory:-
1. CD:- it
stands for compact disk.
v It is a made
up of lightweight plastic material with a chemical coating on one side where data
is stored.
v It is
inserted into CD/DVD ROM drive or CD/DVD writer of a CPU to read its data.
v A CD can store 700MB of data.
2. DVD:- it
stands for the digital versatile disk.
v It is an optical disk that looks like a CD but has the capacity to store data up to 15000 MB
of data.
v It
represent the merging of video and audio in a common format.
v To read
data from this then we have inserted into DVD ROM or DVD Write or DVD player.
3. Blu-ray
Disk:-
It is a
storage disk which can store data up to 25 GB- 50 GB.
It has been
developed by Blu-ray disk Association(BDA).
It is much
advanced than CDs or DVDs.
A blue-violet laser is used to read or write in the Blu-ray-Disk.
4.
FLASH MEMORY:-
Ø It is an external storage device that is commonly used in digital cameras and MP3
players.
Ø It is very
small in size, many users keep it in their key chain.
Ø It is
connected to the computer by USB or Firewire port.
Ø It has
compact shape, operate much faster and hold more data.
Ø It is a more
reliable device.
Ø It is small
in size.
Ø It is
writable, portable, and stores more data than a CD.
Ø It weighs
less than 25 gm.
Ø Initially
it was launched as 64 MB storage capacity but nowadays it can store 32 GB,
128 GB ...etc
Ø It has a USB the port that connects with computer in the USB slot.
Ø It has a
high storage capacity and provides faster speed of data transfer.
Ø The data
stored in memory stick can be read or written with a memory stick-capable
reader.
Ø Memory the stick has different in size such as 1 GB, 128 GB but it can be extended up to
maximum of 2 TB.
Ø It is a
miniature devices and commonly used in digital cameras and mobile phones.
Ø It is available with a different name like MMC( multimedia card), SDC(super dynamic card) , MicroSD card, etc.
OUTPUT DEVICE:- A device that display the output after processing of data is known as output device.
è The user
receives the result through an output device.
è Output can
be in the form of soft, hard copy.
è There are
some common output devices such as
1. Printer
2. Plotter
3. Monitor
4. Speaker
1. Printer:-
it is an output device that is used for printing documents.
è It
generates a hard copy of data or information.
è There are
different types of printer that are based on:-
v Quality of
printing:- the quality of output produced by the printer can be measured in
units of dots per inch which is also termed as resolution.
v Speed:- the
speed of a printer is measured in cps( character per second) or ppm(page per
minutes). The speed of different types of printer varies widely.
v Printing
mechanism:- some printer print by actually striking the printer head on the
paper, some printer print by forming images on the paper...etc.
è Printer can
be classified on the basis of printing mechanism:-
v IMPACT
PRINTER
v NON-IMPACT
PRINTER
Ø It prints
the contents by striking on the printer head against an ink ribbon which rolls
with the cartridge to make a mark on the paper.
Ø There are
two types of impact printer such as
1. Line
printer
2. Character
printer
Øthe printing speed of line printers varies from 300 to 3000 lines per minute.
Ø It is used
due to its high printing speed.
Ø It can be
further divided into two types :
1. Drum
printer
2. Chain
printer
Ø Drum
printing the drum rotates to position the characters. Hammer that lies in the
opposite direction strikes the inked ribbon when the target character of the
drum comes into the printing position.
Ø A drum the printer can print up to 300 to 2000 lines per minute.
Ø There are
hammers in each printing position. During printing, the band is rotated at a
high speed.
Ø It can
print up to 40 to 2500 lines per minute.
Character printer:- A character printer is also called as
serial printer.
Ø It prints the character of the content by character, i.e, it prints a character at a time in
serial order.
Ø It can be
further divided into daisy wheel printer, dot matrix printer..etc.
Daisy wheel printer:- In a daisy
wheel printer as it is named the head of this printer resembles a daisy flower
and the printing arms appear like the petals of the flower.
Ø It uses a
circular printing mechanism said as daisy wheel, each petal of the wheel
contains character embossed in it.
Ø It can
print up to 10 to 50 characters in a second.
Ø It produces
high-resolution output and it also called smart printer because of its
bidirectional printing and multiprocessing control feature.
Ø It is
not used to print graphics.
Dot Matrix printer:- it is the most commonly used printer.
Ø It is also
known as the wire Matrix printer.
Ø In this
printer the printer head contains a matrix of pins.
Ø The
characters are printed by the dots which are formed by striking the pins on the
ribbon.
Ø A printer
head of a dot matrix printer contains, 9 or 24 pins.
Ø Its
printing cost is cheapest than other
printers.
Ø The width
of a dot matrix printer can be 80 or 132 or 136 columns.
Ø It can
print up to 100 to 300 characters in a second.
Ø The
resolution of the printing ranges from 150 to 250 dots per inch(dpi).
NON-IMPACT PRINTER :-
Non- impact printer prints without touching or striking the ribbon on paper or on the film.
Ø This type
of printer prints by using thermal or chemical or electrostatic or laser beam
or inkjet technology.
Ø It has
greater resolution and it is faster as compared to impact printer.
Ø This type
of printer can print colorful content also.
Ø This the printer can be classified into such as-
1. Inkjet
printer 2. Laser printer
Inkjet printer :- an inkjet printer produces high quality of printing.
Ø This the printer has a print head that contains the cartridge that has several tiny
holes through which the ink is sprayed on the paper.
Ø An inkjet the printer can print up to 2 to 10 pages per minute. Its printing is costlier than
that of dot matrix printer but its quality is much better than that and it
prints at a medium pace.
Ø It prints
photo-quality image with resolution of 400 to 4000 dpi.
Laser Printer:- it prints the contents by laser technology.
Ø It is fast
in operation which operates in a similar mechanism as photocopy machines.
Ø The laser
beam makes the shadow of the image with the help of toner and transfers them on
paper.
Ø It is also
known as ‘page printer’ because it actually stores the content of the page in
memory before printing it.
Ø It can
print up to 12-25 pages in a minute and the resolution output ranges from 600
dpi to 2400 dpi.
SPEAKER:- It is an output device that converts the
electrical signals into sound waves that we hear.
Ø In speaker
electric current is supplied to the magnet that pushes the diaphragm of the
speaker back and forth which creates pressure and vibration in the air and that
produces sound.
Ø The quality
of the pitch of a sound depends upon the frequency of the speaker.
Ø In
computers, speakers can be attached internally or externally.
Ø External
speakers are attached to the CPU by wires which are attached to the computer
through audio output jack. Generally, the color of the jack is blue or light
green.
v NOTE:-
i-PAD and i-POD both are small portable the device produced by Apple Macintosh. I-PAD works like a small notebook where we
can type text, play video or music files, access the internet, and play computer
games.
Ø I-pod has fewer features than i-pad. It can store
various digital files like photographs, music, or other data. It is commonly
used to play music and video.
PLOTTER:- it is an output device that helps in creating high-quality
graphics, visuals, charts, graphs, tables, and diagrams, etc.
Ø In plotter
the figures are drawn by an electronic pen that is driven by a motor.
Ø It uses
inkjet cartridges(single or multi-colored) to spray colors for drawing and
sketching.
Ø Plotter can
draw continuous lines and can produce output on paper, polyester film or
colored transparencies.
Ø Plotter is
mostly used in CAD(Computer-Aided Design), CAM(Computer-Aided Manufacturing),
printing Banner and Flex.
CLASSIFICATION OF PLOTTER:-
Ø There are
following classification of plotter such as:-
1. Flatbed
plotter
2. Drum
plotter
3. Micro-graphic
plotter
4. Inkjet
plotter
v Flatbed
plotter:- it is an output device that consists of a fixed horizontal flat
surface on which paper or any other medium is fixed. The pen is mounted on a carriage that moves along the horizontal and vertical axis to print over the
medium.
v Drum
plotter:- it is an output device that consists of one or more pens which moves
across the drum.
Ø The output
medium is placed over the drum.
Ø The drum
rotates either clockwise or anticlockwise under the control of plotting
instructions sent by the computer.
v
Micrographic plotter:- in this type of plotters the paper or other medium is
held on both sides at the edges by pinch wheels which gives back-and-forth the movement to the paper while printing. It does not print over the drum.
vInkjet
plotter:- in this type of plotter jets of ink are used in place of ink pens.
Ø The paper
is placed on drum and inkjet with different colored inks are mounted on a
carriage.
Ø It can
print multi-colored large drawings.
MONITOR:- it is an output device.
Ø It is also
known as VDU(visual display unit).
Ø It is used
for interactive processing, i.e data being fed is displayed on the screen.
Ø It is
connected to the video card or video adapter of the motherboard.
Ø It has
monochrome screen and multicolor screen also.
Ø In
monochrome screen, the picture is display in black and white color. Whereas
in the multicolor screen, the picture is displayed in multicolor.
Ø In the multicolor (color) screen there can be a colour combination of different colors
and can display up to 256000
There are three types of the monitor such as:-
1. CRT
2. LCD
3. LED
1 CRT- it
stands for a cathode ray tube.
Ø It is also
known as a picture tube of the monitor.
Ø It is a
vacuum tube that contains a negatively charged cathode that shoots electrons at
the back of positively charged screen.
Ø The screen
is coated with phosphorus.
Ø The image
we see on the monitor screen that is made
LCD:- it stands for liquid crystal display.
Ø It works on
different technology as compared to CRT.
Ø It is used in a smaller computer like PDAs and Laptops, they are also used in desktop
monitors.
Ø It uses
TFT(thin Film Transistor) which creates sharper and brighter image.
LED:- it stands for Light Emitting Diode.
Ø It is based
on semiconductor technology which produces very high brightness for high image
quality.
Ø It can be
made very thin , which makes them less space-consuming and the user can hang
them anywhere.
Note:- Touch Screen is a special kind of display screen.
Ø It senses the
touch on the screen.
Ø It acts as an
input as well as an output device.
Ø It is used at
information counters of airport, railway station, ATM counters...etc.
Chapter -3
Software
Program:- it is a set of meaningful instructions that perform some tasks.
Ø It is an intangible part of a computer that provides intelligence to the computer.
Ø There are
following category of software such as-
1. Application
software
2. System
software
3. System
utility software
Application software:- it refers to programs which are designed to accomplish specific type of task.
Ø It is
designed to meet users specific needs.
Ø There are
two category of application software such as-
1. Application
package
2. Customized
package
Ø Word processing package, spreadsheet package.. etc
are the example of application package.
Ø It is also
called “tailor made software”.
Ø Inventory
management system , fee collection system ... etc are the example of customized
software.
Ø It is developed
according to the user need.
| System
software:- A software that helps the user to operate and communicate with
computer system.
è It
co-ordinates the operation and functioning of a computer , the attached
peripherals, hardware components of the computer
è It acts as
interface or bridge between the user and the computer.
è System
software broadly classified in two category such as:-
1. Operating
system
2. Language
processor
1. Operating
system :- an operating system is a
system software that acts as an interface between hardware and the user.
è It is
responsible for the management and co-ordination of operation and the sharing of resources of the computer.
è It acts as
a host for applications that run on machine.
Accounting management system:- A system by which we manage
our account is known as accounting management system.
Ø Accounting
management software facilitates to manage the account of an organization.
Ø In
accounting software the operator has to enter the data related to transaction.
Ø It reduces
data redundancy and does all calculations for generating different reports
including profit/loss, balance sheet...etc.
Reservation system:- A system by
which we reserve ticket, hotel..etc is known as reservation system.
Ø We reserve
any thing by the helps of reservation software.
Ø It also
helps in doing transaction related to booking of tickets as per the latest
availability.
Ø This type
of software uses internet to book ticket , hotel ..etc.
Ø This system
helps in keeping data of current status of seats.
H.R management system:- it is one of the biggest
responsibility of an organization.
Ø It involves
a lot of things to be managed from appointments , keeping personal records to
performance evaluation and salary distribution of the people.
Ø The human
resource management software helps to smoothly manage the HR records in a clear
and easy to use format.
Ø It also
helps to keep up-to-date data of employees.
Ø It also
helps in proper management of salary distribution as it is connected to payroll
software.
Ø Utility
software neither completely system software nor application software.
Ø Antivirus ,
c- cleaner ... etc are the example of utility software.
Ø There are
various types of utility software such as:-
1. Disk
defragment utility
2. Disk
checker utility
3. Disk
cleaner utility
4. Disk
partitioner utility
5. Backup
utility
6. Disk
compression utility
7. File
manager utility
Note :- firmware are the small programs that are programmed
on ROM. The firmware helps to do tasks
like keeping time , booting , etc.
Encryption :- it is the process of encoding some confidential
data including password in such a way that only the person with the authorized
key can access the information.
Ø An
unauthorized person cannot access or understand the cipher text.
Ø Encryption
key is usually in the form of files on storage media , removable media , e-mail
message or in the form of packets sent over networks.
Decryption :- it is the process of decoding data for a use or
to access the information that are encrypted and stored in confidential files
or folders.
Ø It converts
the encrypted data back into its original form.
Encryption/ Decryption tool enables to encrypt and decrypt
information of important and confidential files or folders on computer with the
help of sophisticated encryption/decryption algorithm. It is integrated with
the application.
Ø Open SSL ,
Stunnel , OpenVPN , Kremlin Encrypt , Creatcrypt 2.0 ....etc are the example of
encryption/decryption tool.
It has
been a more popular operating system in universities , houses etc. And are
widely used in servers, workstations and mobile devices.
It was
originally developed in 1969 at AT & T Bell Labs.
Initially
it was developed in assembly language but it by 1973 it was re-coded in C.
This is a
multitasking operating system.
It is
also multi user operating system.
It is
multiprocessing operating system.
In this
operating system user does not need to remember all commands.
It was
developed during 1985.
Windows
3.0 , windows 3.1, windows 95 , windows 98 , windows NT , windows 2000 ..etc
are the example of windows operating system.
There are
following features of operating system :-
1.
It is user friendly operating system.
2.
It provides “ Multi tasking “ features that means many application can be
opened at same time.
3.
It is available in GUI(graphical user interface).
4.
It is network friendly.
5.
It supports latest graphics , sound and multimedia software.
Chapter -4
Operating
system
Operating
system :- it is a system software that coordinates the
hardware resources , software and humanware resources.
Ø It provides interface to use the resources
of computer system effectively and efficiently.
Ø It acts as a messenger between the
computer hardware and the application programs by ensuring or by establishing
connection.
Ø There are following program that
makes the operating system are:-
1. Control program
2. Supervisory program
3. Service program
Control
program :- it
controls and manages all the hardware and memory resources of the computer
system.
Ø It regulates the activity of the CPU
and allocate memory space whenever required. It coordinates to schedule the
data to be received or sent through input and output devices.
Supervisory
program :- The
supervisory program controls operations of operating system and application
programs.
Service
program :- The
service program enables proper interaction which provides services to the
users( like saving file , delete and load from CDs ...etc).
Classification
of operating system :-
There are following categories of operating
system such as :-
On the basis of interface :-
There are
following operating system on the basis of interface such as –
1. CUI :- it stands for character user
interface.
Ø The users sends commands and
instructions to the computer in character form by typing at command prompt.
Ø PC-DOS , MS-DOS , UNIX are the
example of CUI based operating system.
2. GUI :- it stands for graphical user
interface.
Ø The interface with figures and graphs
on the screen.
Ø It is basically menu or button based.
Ø Windows 7 , windows 8 ...etc are the
example of GUI based operating system.
ON the basis of Number of
users
There are following operating system on the basis of Number
of users such as –
1. Single user
2. Multi user
1. Single user :- A single user operating system allows
access to single user at a time.
Ø MS-DOS is the example of single user operating
system.
2. Multi user :- it allows to access two
or more users at a time.
Linux , unix are the example of multi user operating system.
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