COMPUTER APPLICATION

What is personal computer?

A computer is a machine that can handle and manipulate data in accordance with the instructions, and is also able to generate visible results on a screen or monitor. Different computer do different kinds of work, a small computer that has been designed to be used by one person, at home or in an office. It is often simply called a PC. 

What is a personal computer?

 A personal computer is a computer small and low cost, which is intended for personal use (or for use by a small group of individuals). The term "personal computer" is used to describe desktop computers (desktops). It is often shortened to the acronym PC or microcomputer, whose meaning in English is "personal computer". It is a very common type of machines.

 

Personal Computer (acronym PC) consists of a Processor (CPU), central processing unit(CPU) contains the arithmetic, logic, and control circuitry on an single (IC) integrated circuit; two types of memory, main memory, such as RAM, and ROM, magnetic hard disks (HDD) and compact discs and various input/output devices, including a display screen, keyboard and mouse, modem, and printer.

History of Personal Computer !

Prior to the Personal Computer (acronym PC), computers were designed for large organization who attached thin terminals for multiple users to a single large computer whose resources were shared among all users. The advent of the personal computer (PC), they break up the tradition of terminals computing. By the late 1980s, technology advances made it feasible to build a small computer that an individual could own and use.

The personal computer began to be wide spread in the 1980s. The first was expensive, work late and had little capacity seen with today's eyes. History shows that they had their antecedents in particular as calculating machines. It was the development of an effective operating system and a user friendly interface which gave impetus to the development and let them be word processors.

According to the Computer History, the first "personal computer" was the Kenbak-1, launched in 1971. Had256 bytes of memory and was advertised in Scientific American for $750, however, did not have CPU and was, like other systems of this era, designed for educational use.


 COMPUTER APPLICATION

 Central Processing Unit (CPU)
Also called a processor, The electronic component that interprets and carries out the basic instructions that operate the computer

Memory
Consists of electronic components that store instructions waiting to be executed and data needed by those instructions

Storage media
Physical material on which data, instructions, and information are stored

Storage device
It Records and retrieves items to and from a storage medium

What is a hard disk?
Provides greater storage capacity than a floppy disk, Zip disk, or USB flash drive

What is a communications device?
Hardware component that enables a computer to send and receive data, instructions, and information
Occurs over cables, telephonelines, cellular radio networks,satellites, and other transmission media

What is the Internet?
Worldwide collection of networks that connects millions of businesses, government agencies, educational institutions, and individuals

Why do users access the Internet?
Communication
Entertainment
Education
Shopping
Banking
Information

What is the Web?
Billions of documents, called Web pages, available to anyone connected to the Internet
A Web site is a collection of related Web pages
A Web page contains text, graphics, sound, video, and links to other Web pages
You can share information by creating Web pages or posting photos on a photo  sharing community

What is software?
Consists of a series of instructions that tells the computer what to do Also called a program

What is a graphical user interface (GUI)?
Allows you to interact with the software using graphics and icons
Controls how you enter data and how  the screen displays information

What is system software?
Programs that control or maintain the operations of the computer and its devices
Operating System (OS) is a set of programs that coordinates all activities among computer hardware devices and allows users to run application software
Utility Programs allow the user to perform maintenance-type tasks usually related to managing a computer, its devices or its programs

What is application software?
It consist of
word
excel
PowerPoint

What are smart phones and smart watches?
A smart phone is an Internet-enabled telephone that usually provides PDA capabilities. A smart watch is an Internet-enabled watch that automatically adjusts to time zone  hanges and stores personal  information.

What is an embedded computer?
A special-purpose computer that functions as a component in a larger product

What are information system elements?
Hardware
Software
Data
People  and Procedures

Features of computer
1. Automatic: a machine is said to be automatic if it works without human intervention, when the job is started it is carried on until the job is finished
2. Speed: a computer is very fast device, it can perform huge amount of work in few second
3. Accuracy: in addition to its speed ,computer are accurate the degree of accuracy of a particular computer depends upon its design, errors can occur in a computer ,and they are caused due to incorrect data.
4. Power of remembering: computer has the power of remembering and storing any amount of data; the data stored can be recalled at any time.
5. No feeling: it does not have any feeling or emotions thus it doesn’t get tiered even after long hours of work
6. Intangible benefits: there are many benefits, such as speed accuracy, storage capacity,etc
7. Reduced cost: with the advanced improvement of technology the cost of the computer has reduced over the years
8. Storage: the computer has an inbuilt storage memory where it can store large amount of data and the storage capacity varies from 40 g.b top 1 tera bite
9. Reliability: the information stored in their computer can be regained, even if the information are lost due to system crash.

Classifications of computer
1. Microcomputer
2. Workstations
3. Minicomputer : Midrange server  Powerful, large computer that supports up to a few thousand computers
4. Mainframe computer: Mainframe  Very powerful, expensive computer that supports thousands of computers
5. Super computers : Supercomputer  The fastest, most powerful, most expensive computer. Used for applications requiring complex mathematical calculations

1. Microcomputer: also known as a personal computer, there are two types of P.C.
a.) Desktops: these computers can fit on a desk, therefore it is called as desktop computers . Designed so all of the components fit entirely on or under a desk or table
b.) Portable: these computers are portable and smaller in size
i. Laptops and Notebooks: Portable, small enough to fit on your lap Also called a laptop computer Generally more expensive than a desktop computer
ii. Palmtops : Small enough to carry in a pocket Internet-enabled telephone is a “smart phone” Small enough to fit in one hand, Used by mobile employees such as meter readers and delivery people
iii. Wearable computers:

Applications of computers
1. Computer in business
2. Computer in industries
3. Computer in science and engineering
4. Computer in education
5. Computer in health care
6. Application of computer in graphics
7. Multimedia applications
Advantages of computer
Disadvantages of computer
Violation of Privacy
Impact on Labor Force

Basic Concepts of Computer

> Machine Language

Machine language or machine code is the native language

directly understood by the computer’s central processing unit

or CPU. This type of computer language is not easy to

understand, as it only uses a binary system, an element of

notations containing only a series of numbers consisting of

one and zero, to produce commands.

>Assembly Level Language

Assembly Level Language is a set of codes that can run

directly on the computer’s processor. This type of language

is most appropriate in writing operating systems and

maintaining desktop applications. With the assembly level

language, it is easier for a programmer to define commands.

It is easier to understand and use as compared to machine

language.

>High Level Language

High Level Languages are user-friendly languages which are

similar to English with vocabulary of words and symbols.

These are easier to learn and require less time to write.

They are problem oriented rather than ‘machine’ based.

Program written in a high-level language can be translated

into many machine languages and therefore can run on any

computer for which there exists an appropriate translator.

>Compiler & Interpreter

These are the programs that execute instructions written in

a high-level language. There are two ways to run programs

written in a high-level language. The most common is to

compile the program; the other method is to pass the program

through an interpreter.

a.

Compiler

A compiler is a special program that processes statements

written in a particular programming language called as

source code and converts them into machine language

or “machine code” that a computer’s processor uses.

Computer and Office Applications

Compiler translates high level language programs directly

into machine language program. This process is called

compilation. (Fig 1.11)

Fig. 1.11: Compilation

b.

Interpreter

An interpreter translates high-level instructions into an

intermediate form, which it then executes. Compiled

programs generally run faster than interpreted programs.

The advantage of an interpreter, however, is that it does

not need to go through the compilation stage during which

machine instructions are generated. This process can be

time-consuming if the program is long. (Fig 1.12)

Fig. 1.12: Interpretation

1.6.5 Open source software:

Open source refers to a program or software in which the

source code (the form of the program when a programmer

writes a program in a particular programming language) is

available to the general public for use and/or modification

from its original design free of charge.

Open source code is typically created as a collaborative effort

in which programmers improve upon the code and share the

changes within the community.

Basic Concepts of Computer

The rationale for this movement is that a larger group of

programmers not concerned with proprietary ownership or

financial gain will produce a more useful and bug-free product

for everyone to use.

The basics behind the Open Source Initiative is that when

programmers can read, redistribute and modify the source

code for a piece of software, the software evolves.  Open source

sprouted in the technological community as a response to

proprietary software owned by corporations.

Proprietary software is privately owned and controlled. In

the computer industry, proprietary is considered the opposite

of open. A proprietary design or technique is one that is owned

by a company. It also implies that the company has not

divulged specifications that would allow other companies to

duplicate the product.

>OPERATING SYSTEM

An operating system is a software component of a computer

system that is responsible for the management of various

activities of the computer and the sharing of computer

resources. It hosts several applications that run on a

computer and handles the operations of computer hardware.

Users and application programs access the services offered

by the operating systems, by means of system calls and

application programming interfaces. Users interact with a

computer operating system through Command Line

Interfaces (CLIs) or Graphical User Interfaces known as GUIs.

In short, an operating system enables user interaction with

computer systems by acting as an interface between users

or application programs and the computer hardware. Some

of the common operating systems are LINUX, Windows,etc.

>WINDOWS XP DESKTOP ELEMENTS

Start Menu

When clicked on the start button, start menu appears on

the screen giving all the available options to start using the

>Computer and Office Applications

Windows (See Fig. 1.13). Desktop icons provide access to

commonly used programs, folders and files.

Fig. 1.13

Overview of the options available in the start menu.

Task

Description

All Programs

Displays a list of installed program,

which a user can start or use

My Documents

Displays a list of documents used by

the current user

My Recent Documents

Displays a list of recently used

documents by the current user

My Picture

Displays a list of pictures/photos used

by the current user

My Music

Displays a list of music/songs used by

the current user

Control Panel

Displays a list of utilities to configure

the computer system and install

software and hardware

Printers and Faxes

Displays a list of currently installed

printers and faxes in the current

computer system

Basic Concepts of Computer

Help and Support

Start the XP help and support program

to find how to do a task in windows

Search

Helps the user to find any file or folder

from a list of document used by the

current user.

Run

Starts an application program or

executes a DOS command

Log Off

Log off the currently logged in user of

the system

Turn Off Computer

Close currently opened program, log

off the current user and switch off the

computer system.

Task Bar

When you start the computer system, then start button and

task bar appears on the bottom of the screen and by default

remains visible when Windows is running (See Fig. 1.14).

Whenever a program is run or a window is opened, an icon

representing the program appears on the taskbar. To switch

between windows or program, click on the icon representing

the window on the task bar. When the program or window

is closed, the icon disappears from the task bar.

Task bar

System Tray

Fig. 1.14

The system tray is part of the task bar and displays the

current time as well as the status icons.

1.8.1 Start a Program

To start a program, do the following;

1.

Click on the

Start

Button.

2.

Click on the

All Programs,

you will see a list of all

the program icons and program folders.

3.

Point to the desired folder say

Accessories

and select

the desired program to run such as

Paint.

18 :: Computer and Office Applications

1.8.2 Quit a Program

To quit a program, select the close button

(×)

in the upper-

right corner of the window OR

Click on

File

menu and select

Close

option.

1.8.3 Getting Help

Online help and support provided is of great help in using

and learning windows. One can get help on a specific topic

or on current task which is being executed. To start help



click on the

Start

button



click on

Help and support

option

A list of help and support topics and online tutorial is

displayed on the screen (see Fig. 1.15). One can use the tabs

in the screen to search for the desired information in several

ways.

Fig. 1.15



Click on a topic or task to know more about how to get

the job done or type in a search word to locate the help

on a specific topic.

Basic Concepts of Computer

:: 19



Click on the

Index

tab to locate specific topic listed

alphabetically and the follow the instructions displayed

on the screen.



Click on

Favourites

tab to add Help Topics, search

results to your Favourites list to make them easy to

locate in the future



Click on

History

to pick from a list of Help and Support

pages that you have read in the past.



Click on

Support

to get various kind of online support

such as Microsoft online support, News Group on

Windows.



Click on

Option

to configure the help and support

center as per your requirement.

To close Help and Support windows, select the close button

(×) in the upper-right corner of the window.

1.8.4 Searching Files and Folders

If you don’t know where a document or folder is located,

you can use the Search option to locate it in the local storage

such as Hard Disk, CD or in the network drive (if the system

is part of a network). The Indexing Service provided by the

Search maintains an index of all the files on your computer,

making searches faster.

To search for a file or folder

1.

Click

Start

, and click on

Search

.

2.

Select

All files and folders

from the left hand side

of the windows (see Fig. 1.16).

3.

Type the name of the file or folder in part or full, or

type a word or phrase that exists in the file to be

searched.

4.

If you do not know either piece of information select

one or more of the remaining options:



In

Look in

, click the drive, folder, or network

you want to search.

20 :: Computer and Office Applications

Fig. 1.16



Click on

When was it modified?

to look for files

that were created or modified on or between

specific dates.



To look for files of a specific size, click on

What

size is it?

Select a size.



Click on

More advanced options

to specify

additional search criteria.

5.

Once you finish specifying the search criteria, click on

Search to

locate the file.

Similarly you can search for specific information on

Internet, or people in your address book, search for

a printer or a computer on your network.

1.8.5 Changing System settings

By using Control Panel’s tools you can customize the way

Windows look and work! Also you can install new hardware,

add and remove (install/uninstall) software programs, change

the look and feel of your desktop and much more. It also

includes a number of administrative tools in Administrative

Basic Concepts of Computer

:: 21

Tools option for better administration of Windows in terms

of User Management, Event viewer, Component Service etc.

To start Control Panel and use the available tool, do the

following;



Click on

Start



Click on

Control Panel



Select the desired tool to use

For example to create a new or modify the settings for an

existing user click on ‘User Account’ icon in the control

panel.

1.8.6 Using 'My Computer'for browsing your disk

drives

Your disk drives hold all the information on your computer:

all the files, folders, programs as well as the documents.

My Computer displays the contents of floppy, hard disk,

CD-ROM, and network drives. One can also search for and

open files and folders, and use options in Control Panel to

modify computer’s settings.



To use My Computer, click on

Start

, and then click

on

My Computer

or double click the

My computer

icon on the desktop. My computer windows opens

to show all the drives present on your computer. (see

Fig. 1.17).

Fig. 1.17

22 :: Computer and Office Applications

Display the storage Contents



To see what’s on your hard disk, under

Hard Disk

Drives

, double-click the drive you want to see such

as C:, D: etc.



To find a file or folder on a CD-ROM, or other media,

under

Devices with Removable Storage

, double-

click on the respective storage media you want to see.



To find a file in a folder, under

Files Stored on This

Computer

, double-click a folder.

1.9 FILE MANAGEMENT IN WINDOWS

File management in windows can be done through Windows

Explorer or My Computer. Windows Explorer displays the

hierarchical list of files, folders, and storage drives (both fixed

and removable) on your computer. It also lists any network

drives that have been mapped to as a drive letters on your

computer. Windows Explorer can be used to copy, move,

rename, and search for files and folders. For example, to copy

a file, you can open a folder that contains the desired file to

be copied or moved, and then just drag and drop the file to

target folder or drive. (see fig. 1.18)

Fig. 1.18

Basic Concepts of Computer

:: 23

When files or folders are deleted from hard disk, Windows

places them in the Recycle Bin, from where they can be

retrieved, until the Recycle Bin is made empty. Files or folders

deleted from a removable storage media such as network drive

are permanently deleted and are not sent to the Recycle Bin.

1.9.1 Using Windows Explorer

Windows offer another utility "Windows Explorer" which helps

you in working with files and folders on your computer.

To open Windows Explorer,



Click on

Start

,



Point to

All Programs

,



Point to

Accessories

, and then click on

Windows

Explorer

(see Fig. 1.19)

Fig. 1.19

The left pane of the Explorer window shows a hierarchy of all

the drives, folders and desktop items on your computer. A

drive or folder that contains other folders has a plus sign to

the left of the icon. Click the plus sign to expand it and see

the folders inside. (see Fig. 1.20)

24 :: Computer and Office Applications

1.9.2 Opening drives and folders

Two drives nearly all computers have are a floppy drive (drive

A:) and a hard drive (drive C:). If you have more than one drive,

then they are named D:, E: and so on. If you have a CD drive

or a DVD drive, it also is named with a letter. Opening a hard

drive is easy. Just double click the icon representing the drive

you want to open. Files and folders contained in the drive are

now shown in the opened window. Now for opening a folder,

double click its icon.

Fig. 1.20

1.9.3

Copying or Moving a file or Folder using

My Document



Click on

Start

, and then click on

My Documents

.



Click the file or folder to be copied. More than one file

or folder can be copied at a time.



To select more than one consecutive files or folders,

click the first file or folder, press and hold down SHIFT

key, and then click the last files or folders.



To select non-consecutive files or folders, press and

hold down CTRL key, and then click each of the files

or folders to be copied.

Basic Concepts of Computer

:: 25



Under

Edit menu,

select

Copy.



Select the target drive or folder to which you want to

copy the files



Under

Edit menu

, select

Paste

to copy the desired file

or folder to the target drive.

1.9.4 View file details

1.

Click on

Start

, and then click on

My Documents.

2.

Double-click the folder that contains the files to be

viewed.

3.

On the

View

menu, click

Details

(see Fig. 1.21).

4.

It will display all the details about the files such as

Name, Type, size etc.

Fig. 1.21

1.9.5 Copying and moving files using Explorer



Click

Start

, point to

All Programs

, point to

Accessories

,

and then click

Windows Explorer

.



Make sure the destination for the file or folder you want

to move is visible (see Fig. 1.22).

26 :: Computer and Office Applications

Fig. 1.22



Drag the file or folder from the right pane and drop it

on to the destination folder in the left pane to move the

file or folder there.



If you drag an item while pressing the right mouse

button, you can move, copy, or create a shortcut to the

file in its new location.



To copy the item instead of moving it, press and hold

down CTRL while dragging.



If you drag an item to another disk, it is copied, not

moved. To move the item, press and hold down SHIFT

while dragging.



Dragging a program to a new location creates a shortcut

to that program. To move a program, right-click and

then drag the program to the new location.

1.9.6 Create a new folder

Folders help you to organize your files. You can create a folder

either by using My Computer window or through Windows

Explorer. You can create a Folder in any existing disk drive

or folder or on the windows desktop. The steps for creating

a folder are:

Basic Concepts of Computer

:: 27

1.

Click on

Start

, and then click on

My Documents

2.

Under

File

menu click

New

and select

Folder

. (see Fig.

1.23)

3.

A new folder is displayed with the default name,

New

Folder

.

4.

Type a name for the new folder, and then press ENTER.

5.

A new folder can also be created directly on the desktop

by right-clicking a blank area on the desktop, pointing

to

New

, and then clicking

Folder

.

1.9.7 Rename a file or folder

1.

Click on

Start

, and then click on

My Documents

2.

Click on the file or folder you want to rename.

3.

Under

File

menu click on

Rename

(see Fig. 1.23).

4.

Type the new name, and then press ENTER key.

5.

Alternately file or folder can also be renamed by right-

clicking it and then clicking on

Rename

.

1.9.8 Delete a file or folder

1.

Click on

Start

, and then click on

My Documents

2.

Click on the file or folder you want to delete.

3.

Under

File

menu click on

Delete

(see Fig. 1.23).

4.

Files or folders can also be deleted by right-clicking the

file or folder and then clicking

Delete

.

5.

Deleted files or folders are stored in the

Recycle Bin

,

till they are permanently removed from the Recycle Bin.

6.

To retrieve a deleted file, double-click the

Recycle Bin

icon on the desktop. Right-click on the file to be

retrieved, and then click

Restore

.

7.

To permanently delete a file, press and hold down SHIFT

key and drag it to the Recycle Bin.

28 :: Computer and Office Applications

Fig. 1.23

1.10 COMPUTER SECURITY

Security has always been an overriding concern of human

kind. For many organization, information plays a very important

role in running business. Therefore, it becomes necessary to

safeguard information from reaching the illegal hands. When

data takes the shapes of digital form, a different security

procedure is required. This branch of security is called

computer security.

Information technology has also some loopholes associated

with it, like the possibility of stealing of vital information and

intentionally implanting destructive or malicious programs on

the other's computer system. The motive behind such activities

is to show down the pace of an organization and harm it

economically. We shall discuss now about these malicious

programs which are often called virus, worms, Trojan horse,

logic bomb, spyware and so on.

Basic Concepts of Computer

:: 29

1.10.1 Virus

Virus is a program which has been written to interfere with

the normal functioning of the computer. It does this by

clogging the memory of the system by making copies of itself

or it may destory critical information used by other computer

prgrams.

There are three main types of viruses:

Boot sector viruses

which infect the boot sector in the hard disk and affect the

partition table,

File viruses

attach with executable files. The

commonly infected files are those with COM or EXE extensions.

The third,

System viruses

infect specific system files such

as command.com. Computer viruses can be grouped into

Time Bomb, Trojan Horse, Worm etc. Time Bomb will start

on a particular date, at a particular time. The computer will

loose its ability to function properly.

The virus known as Trojan Horse will enter into a computer

through an e-mail or free programs that have been down

loaded from the internet and casue plenty of damage. Viruses

known as Worms are constructed to infiltrate on the legitimate

data processing programs and alter or destroy the data. Worm

programs often use network connections to spread from one

computer system to another system, thus, worms attach

system that are linked through communication lines.

1.10.2 Protecting computer system using antivirus

software

In case the virus is present, it becomes our duty to use some

anti-virus software for preventing virus attacks in future.

Anti-virus software falls into two categories: Scanners and

Integrity checkers.

A scanner is a program that will detect the virus by checking

the files on the disk, the boot sector of the disk and programs

in the memory by looking for the signature of the virus. The

signature is a piece of program code that is unique to the

virus. It is very necessary to update regularly the virus

scanner that you have bought. This is essential because new

viruses are constantly appearing.

30 :: Computer and Office Applications

Integrity checkers work using simple checksums or complicated

algorithms or cryptographic checksums which check if a file

has been modified. It may be boring for you to check for virus

every time you run the system. But you should not worry. Help

is at hand with HomeGuard a unique device which once fitted

to the computer automatically scans in the background for

viruses. If there are viruses found in the system, HomeGuard

will clean it up automatically without even having to press a

key.

1.10.3 Precautions to be taken against viruses



Install a memory-resident program in RAM that will detect

and warn if a virus is present.



Do not allow hardware engineers or sales persons to put

a write enabled floppy into your computer uless they can

guarantee that it is not infected.



Backup copies of all programs and data files should be

kept.



Backup copies of programs should be held as read-only

disks to prevent infection.



At least 2 copies of the backup must be kept.



Never boot your machine with a floppy from an unknown

source.



Always write-protect your disk when you use it in another

machine.

INTEXT QUESTION 1.1

1.

What are the characteristics of a computer?

2.

How many types of printers are commonly used?

3.

State TRUE or FALSE

(a)

All code or data is stored and processed in computers

using two symbols; 0 and 1.

(b)

Machine code is also known as source code.

Basic Concepts of Computer

:: 31

1.11 WHA

T YOU HAVE LEARNT

In this lesson, you have learnt about computer organization,

its characteristics (speed, accuracy, diligence, versatility, and

storage capacity) that have contributed towards making it such

a popular device. The differences between concepts like

hardware/software, system/application software, ROM/RAM

was also explained. Various types of input, output and

secondary storage devices along with their usages, were also

studied.

1.12 TERMINAL QUESTIONS

1.

What are the basic units of a computer system?

2.

What is application software? Explain with the help of

examples.

3.

Write short notes on

a.

Operating system

b.

Compiler

c.

Assembly language

d.

Control unit

1.13 ANSWER TO INTEXT QUESTIONS

Intext Question 1.1

1.

Computer characteristics :



Speed



Accuracy