Computer Applications

Chanderprabhu Jain College of Higher Studies & School of Law
Plot No. OCF, Sector A-8, Narela, New Delhi – 110040
(Affiliated to Guru Gobind Singh Indraprastha University and Approved by Govt of NCT of Delhi & Bar Council of India)
Semester: FIRST Semester
Name of the Subject:
COMPUTER APPLICATIONS

2
What Is A Computer?
A computer is an electronic device, operating
under the control of instructions (software) stored
in its own memory unit, that can accept data
(input), manipulate data (process), and produce
information (output) from the processing.
Generally, the term is used to describe a
collection of devices that function together as a
system.

3
Devices that comprise a computer system
Printer
(output)
Monitor
(output)
Speaker
(output)
Scanner
(input)
Mouse
(input)
Keyboard
(input)
System unit
(processor, memory…)
Storage devices
(CD-RW, Floppy, Hard
disk, zip,…)

4
What Does A Computer Do?
Computers can perform four general operations,
which comprise the information processing cycle.
 Input
 Process
 Output
 Storage

5
What Do Computers Do?
• Input, Process, Output, & Store data
Input Process Output
Store Data

6
Data and Information
• All computer processing requires data, which is a collection of raw
facts, figures and symbols, such as numbers, words, images, video and
sound, given to the computer during the input phase.
• Computers manipulate data to create information. Information is
data that is organized, meaningful, and useful.
• During the output Phase, the information that has been created is put
into some form, such as a printed report.
• The information can also be put in computer storage for future use.

7
Why Is A Computer So Powerful?
• The ability to perform the information processing
cycle with amazing speed.
• Reliability (low failure rate).
• Accuracy.
• Ability to store huge amounts of data and
information.
• Ability to communicate with other computers.

8
How Does a Computer Know what to
do?
• It must be given a detailed list of instructions, called a
compute program or software, that tells it exactly
what to do.
• Before processing a specific job, the computer
program corresponding to that job must be stored in
memory.
• Once the program is stored in memory the compute
can start the operation by executing the program
instructions one after the other.

9
What Are The Primary Components Of A
Computer ?
• Input devices.
• Central Processing Unit
(containing the control
unit and the
arithmetic/logic unit).
• Memory.
• Output devices.
• Storage devices.

10
Uses of Computer
PC at Home
Common uses for the computer within the home
• Computer games
• Working from Home
• Banking from Home
• Connecting to the Web

11
Uses of Computer
Office Applications
Stock Control
Stock control is ideal for automation and in many
companies it is now completely computerized. The stock
control system keeps track of the number of items in
stock and can automatically order replacement items
when required.
Accounts / Payroll
In most large organizations the accounts are maintained
by a computerized system. Due to the repetitive nature of
accounts a computer system is ideally suited to this task
and accuracy is guaranteed.

12
Uses of Computer
Automated Production Systems
Many car factories are almost completely automated and the
cars are assembled by computer-controlled robots. This
automation is becoming increasingly common throughout
industry.
Design Systems
Many products are designed using CAD (Computer Aided Design)
programs to produce exact specifications and detailed drawings
on the computer before producing models of new products.

13
Uses of Computer
Computers in Daily Life
• Accounts
• Games
• Educational
• On-line banking
• Smart ID cards
• Supermarkets
• Working from home (Tele-working)
• Internet

15

16

17

18

19

20

21

22

23

24

25

26

27
• Software is a set of electronic instructions that tells the computer how to
do certain tasks. A set of instructions is often called a program.
• When a computer is using a particular program, it is said to be running
or executing the program.
• The two most common types of programs are system software and
application software.
Bringing the Machine to Life –
What is Software?

28

29
• System software exists primarily for the computer itself, to help the
computer perform specific functions.
• One major type of system software is the operating system (OS). All
computers require an operating system.
• The OS tells the computer how to interact with the user and its own
devices.
• Common operating systems include Windows, the Macintosh OS, OS/2,
and UNIX .
Bringing the Machine to Life –
System Software

30
• Application Software consists of programs that tell a
computer how to produce information
• Application software tells the computer how to
accomplish tasks the user requires, such as creating a
document or editing a graphic image.
• Some important kinds of application software are:
Word processing programs Spreadsheet software
Database management Presentation programs
Graphics programs Networking software
Web design tools and browsers Internet applications
Communications programs Utilities
Entertainment and education Multimedia authoring
Bringing the Machine to Life - Applications

What is an Operating System?
• A program that acts as an intermediary
between a user of a computer and the
computer hardware.
• Operating system goals:
– Execute user programs and make solving user
problems easier.
– Make the computer system convenient to use.
• Use the computer hardware in an efficient
manner.

Computer System Structure
• Computer system can be divided into four components
– Hardware – provides basic computing resources
• CPU, memory, I/O devices
– Operating system
• Controls and coordinates use of hardware among various
applications and users
– Application programs – define the ways in which the system
resources are used to solve the computing problems of the users
• Word processors, compilers, web browsers, database systems,
video games
– Users
• People, machines, other computers

Four Components of a Computer System

Operating System Definition
• OS is a resource allocator
– Manages all resources
– Decides between conflicting requests for
efficient and fair resource use
• OS is a control program
– Controls execution of programs to prevent
errors and improper use of the computer

Operating System Definition (Cont.)
• No universally accepted definition
• “Everything a vendor ships when you order an
operating system” is good approximation
– But varies wildly
• “The one program running at all times on the
computer” is the kernel. Everything else is either a
system program (ships with the operating system)
or an application program

Computer Startup
• bootstrap program is loaded at power-up or
reboot
– Typically stored in ROM or EEPROM, generally
known as firmware
– Initializates all aspects of system
– Loads operating system kernel and starts
execution

Computer System Organization
• Computer-system operation
– One or more CPUs, device controllers connect
through common bus providing access to shared
memory
– Concurrent execution of CPUs and devices
competing for memory cycles

Computer-System Operation
• I/O devices and the CPU can execute
concurrently.
• Each device controller is in charge of a particular
device type.
• Each device controller has a local buffer.
• CPU moves data from/to main memory to/from
local buffers
• I/O is from the device to local buffer of controller.
• Device controller informs CPU that it has finished
its operation by causing an interrupt.

Common Functions of Interrupts
• Interrupt transfers control to the interrupt service
routine generally, through the interrupt vector, which
contains the addresses of all the service routines.
• Interrupt architecture must save the address of the
interrupted instruction.
• Incoming interrupts are disabled while another
interrupt is being processed to prevent a lost interrupt.
• A trap is a software-generated interrupt caused either
by an error or a user request.
• An operating system is interrupt driven.

40
Firmware
• Firmware are programs that are permanently
written and stored in memory

41
Computer Software
Computer software is the key to productive use
of computers. Software can be categorized into
two types:
 Operating system software
 Application software.

42
Operating System Software
Operating system software tells the computer how to
perform the functions of loading, storing and executing an
application and how to transfer data.
Today, many computers use an operating system that has a
graphical user interface (GUI) that provides visual clues such
as icon symbols to help the user. Microsoft Windows 98 is a
widely used graphical operating system. DOS (Disk Operating
System) is an older but still widely used operating system
that is text-based.

43
Application Software
Application Software consists of programs that tell a
computer how to produce information. Some of the more
commonly used packages are:
 Word processing
 Electronic spreadsheet
 Database
 Presentation graphics

44
Word Processing
• Word Processing software is used to create and print
documents. A key advantage of word processing software
is that users easily can make changes in documents.

45
Electronic Spreadsheets
• Electronic spreadsheet software allows the user to add,
subtract, and perform user-defined calculations on rows
and columns of numbers. These numbers can be changed
and the spreadsheet quickly recalculates the new results.

46
Database Software
• Allows the user to enter, retrieve, and update data in an
organized and efficient manner, with flexible inquiry and
reporting capabilities.

47
Presentation Graphics
• Presentation graphic software allows the user to create
documents called slides to be used in making the
presentations. Using special projection devices, the slides
display as they appear on the computer screen.

Spreadsheets Basics• Spreadsheet is a computerized ledger
• Divided into Rows and Columns
• Excel is a “spreadsheet” which holds different
kinds of information
• It performs calculations with mathematical
and statistical functions
• It presents your information in a variety of
ways, with visually interesting charts and
graphs
• Constants - entries that do not change
• Formulas - combination of constants and
functions
• Spreadsheet is generic term; Worksheet is an
Excel term
• Workbook contains one or more worksheetsChanderprabhu Jain College of Higher Studies & School of Law

Why to Study it?

Absolute vs. Relative references

Copying formulas does not always
work
This formula calculates first-quarter sales as a percentage of total year sales.
Not surprisingly, it divides the number in cell B4 ($1,000) by the number in cell F4 ($4,100).
However, when you pull the extension handle to copy the formula for Quarters 2,3, and 4, you don’t get the results you want.
Press the Page Down key several times to see what happens.
#DIV/0! means Excel is trying to tell you that you have asked it to divide by 0 -- an operation for which there is no answer.
Why is this happening?

Formula references
To understand why this may be so, consider what the above formula is really saying.
To Excel, B4/F4 actually translates as “when I’m sitting in cell B5, divide the number that is one row above me by the number that is four columns to my
right and one row up.”
In other words, the formula as written tells Excel to make a calculation relative to the cursor’s current position. Remember: the cursor always tells to
Excel its current location (note B5 in the name box above).
What you need to do for the formula to copy correctly is to tell Excel always to use the $4,100 (i.e., the contents of cell F4) -- no matter where you copy
the formula.
To do this, you need to make the reference to cell F4 an absolute reference rather than a relative reference. Use Page Down to see how to do this.

Use the F4 key for absolute references
The screen above shows the formula corrected so that it will give the desired results after it is copied.
To convert a relative reference to an absolute reference while building a formula, press the F4 key immediately after clicking on the
desired location with the cursor (in this case, the immediately after selecting the cell that has $4,100 in it).
The formula changes to show a $ in front of both the column and the row for that location.
You will notice that if you continue to press the F4 key, the command toggles to set the column, then the row, then both as absolute
references.
Trivia: Excel uses the $ to indicate absolute references because in the early days of spreadsheets PC keyboards had so few keys that software designers had to find
multiple uses for each symbol. The company that first did this now out of business, but the $ stuck.

Use the F4 key for absolute references
This screen shows the result after you copy a formula that is correctly referenced.
Use the Page Down key to walk through the steps.
When you’re done, use Page Down to see a sequence that shows setting the absolute
reference.

Setting an absolute reference
The F4 key has been pressed to right here to lock this location as an absolute reference.
This time, all the copied formulas refer correctly to the $4,100 because that location has been set in
the original formula as an absolute reference.
You can check the results by looking at the copied formulas. They all refer to $F$4.

Using Functions in Excel
• Use spreadsheets in decision making; use Goal Seek
and Scenario Manager to evaluate multiple conditions
• Use financial functions (PMT, etc.)
• Use fill handle and AutoFill capability
• Use pointing to create a formula
• Statistical Functions — MAX, MIN, AVERAGE, COUNT
• Use functions over arithmetic expressions
• Decision making functions (IF and VLOOKUP (vertical
lookup))

Excel Built-In FunctionsSUM
AVERAGE
SIN
IF
AND
COUNT
COUNTIF
Many More … (look at Help and fx)

SUM(number1, number 2,…)
• Example
=SUM(3, 2) equals 5
• If cells A2:E2 contain 5, 15, 30, 40, and 50:
=SUM(A2:C2) equals 50 =SUM(B2:E2,
15) equals 150

AVERAGE(number 1, number 2,…)
• Examples
If A1:A5 is named Scores and contains the
numbers 10, 7, 9, 27, and 2, then:
=AVERAGE(A1:A5) equals 11
=AVERAGE(Scores) equals 11
=SUM(A1:A5)/COUNT(A1:A5) equals 11

SIN(number)
• IMPORTANT NOTE:
– Angle (number) must be provided in radians If your
argument is in degrees, multiply it by PI()/180 to convert
it to radians.
=SIN(PI()) equals 1.22E-16, which is approx. 0
=SIN(PI()/2) equals 1
=SIN(30*PI()/180) equals 0.5, the sine of 30
degrees

COUNT
• COUNT counts the number of cells that contain
numbers & numbers within the list of arguments.
• Value 1, 2,…, are 1 to 30 arguments that can
contain or refer to a variety of different types of
data, but only numbers are counted.
• Ex., If cells A1:A17 contain some data, then
=COUNT(A1:A17) equals 17
=COUNT(A6:A17) equals 12

COUNTIF(range,criteria)
Counts the number of cells within a range that
meet the given criteria.
Suppose A3:A6 contain "apples", "oranges",
"peaches", "apples", respectively:
COUNTIF(A3:A6,"apples") equals 2
Suppose B3:B6 contain 32, 54, 75, 86, respectively:
COUNTIF(B3:B6,">55") equals 2

(A4:A130,1)
(A4:A130,2)
(A4:A130,3)
(A4:A130,4)
(A4:A130,5)
=COUNTIF(A4:A130,1)
=D4/D9*100

Some Useful Functions
• IF
• TIME
functions

Conditional Functions
• Conditional functions allow the software to
perform conditional tests and evaluate a
condition in your worksheet. Depending on
whether the condition is true or false,
different values will be returned to the cells.
• =IF is the most important conditional function

If
=IF(condition, action if true, action if false)
This tests the “condition” to determine if specific
results or cell contents are true or false.
If the result of the test is true, the “action if true” is
executed. If the result is false, the “action if
false” portion contains another set of instructions
to execute.
The instructions to be executed can return cell
contents that are labels as well as values.

Logical Operators
• To perform conditional tests, logical operators
are required.
= Equal
< Less than
> Greater than
<= Less than or Equal to
>= Greater than or Equal to
<> Not Equal

Logical Functions
And(logical1, logical2)Returns true if each
condition is true
Or(logical1, logical2) Returns true if either
condition is true
Not(logical) Returns true if the
condition is
false
True() Always returns true

Examples
=IF(A5>20, B5, 0) means that if the value in A5 is
greater than 20, use the value in B5.
Otherwise assign the number 0.
=IF(AND(B11<>0,G11=1),10,0) means that if the
value in B11 is not equal to 0 and the value in
G11 is equal to 1, assign the number 10.
Otherwise, assign the number 0.
=IF(OR(E13=“Profit”,F15>G15),”Surplus”,”Deficit”)
means that if either E13 contains the word
“Profit” or the contents of F15 are greater than

VLOOKUP Function
• Searches for a value in the leftmost column of
a table, and then returns a value in the same
row from a column you specify in the table.
Use VLOOKUP instead of HLOOKUP when your
comparison values are located in a column to
the left of the data you want to find.
Syntax:
=VLOOKUP(lookup_value,table_array,
col_index_num,range_lookup)
– If range_lookup is TRUE, the values in the first

VLOOKUP Function (cont’d)
• Example:
On the preceding worksheet, where the range A4:C12 is named Range:
– VLOOKUP(1,Range,2) equals 2.17
– VLOOKUP(1,Range,3,TRUE) equals 100
– VLOOKUP(.746,Range,3,FALSE) equals 200
– VLOOKUP(0.1,Range,2,TRUE) equals #N/A, because 0.1 is less than the smallest value
in column A
– VLOOKUP(2,Range,2,TRUE) equals 1.71

Functions within functions
• You can use functions within functions.
Consider the expression
=ROUND(AVERAGE(A1:A100),1).
– This expression would first compute the average
of all the values from cell A1 through A100 and
then round that result to 1 digit to the right of the
decimal point

Networking
• Computer network A collection of computing devices
that are connected in various ways in order to
communicate and share resources
Usually, the connections between computers in a
network are made using physical wires or cables
However, some connections are wireless, using radio
waves or infrared signals

15-78
Networking
• The generic term node or host refers to any
device on a network
• Data transfer rate The speed with which data
is moved from one place on a network to
another
• Data transfer rate is a key issue in computer
networks

15-79
Networking
• Computer networks have opened up an entire
frontier in the world of computing called the
client/server model

15-80
Networking
• File server A computer that stores and
manages files for multiple users on a network
• Web server A computer dedicated to
responding to requests (from the browser
client) for web pages

15-81
Types of Networks
• Local-area network (LAN) A network that
connects a relatively small number of
machines in a relatively close geographical
area

15-82
Types of Networks
• Various configurations, called topologies, have been used to administer LANs
– Ring topology A configuration that connects all nodes in a closed loop on which messages
travel in one direction
– Star topology A configuration that centers around one node to which all others are
connected and through which all messages are sent
– Bus topology All nodes are connected to a single communication line that carries messages
in both directions

Types of Networks
Various network topologies
15-10

15-84
Types of Networks
• Wide-area network (WAN) A network that
connects two or more local-area networks over a
potentially large geographic distance
Often one particular node on a LAN is set up to serve as a
gateway to handle all communication going between that
LAN and other networks
Communication between networks is called
internetworking
The Internet, as we know it today, is essentially the
ultimate wide-area network, spanning the entire globe

15-85
Types of Networks
• Metropolitan-area network (MAN) The
communication infrastructures that have been
developed in and around large cities

15-86
Internet Connections
• Internet backbone A set of high-speed
networks that carry Internet traffic
These networks are provided by companies
such as AT&T, GTE, and IBM
• Internet service provider (ISP) A company
that provides other companies or individuals
with access to the Internet

15-87
• There are various technologies available that you can use to
connect a home computer to the Internet
– A phone modem converts computer data into an analog audio
signal for transfer over a telephone line, and then a modem at the
destination converts it back again into data
– A digital subscriber line (DSL) uses regular copper phone lines to
transfer digital data to and from the phone company’s central
office
– A cable modem uses the same line that your cable TV signals come
in on to transfer the data back and forth

15-88
• Broadband A connection in which transfer speeds
are faster than 128 bits per second
– DSL connections and cable modems are broadband
connections
– The speed for downloads (getting data from the Internet
to your home computer) may not be the same as uploads
(sending data from your home computer to the Internet)

Packet Switching
• To improve the efficiency of transferring information over a
shared communication line, messages are divided into fixed-
sized, numbered packets
• Network devices called routers are used to direct packets
between networks
Figure 15.4
Messages
sent by
packet
switching
15-18

15-90
Open Systems
• Proprietary system A system that uses technologies
kept private by a particular commercial vendor
One system couldn’t communicate with another, leading to
the need for
• Interoperability The ability of software and hardware
on multiple machines and from multiple commercial
vendors to communicate
Leading to
• Open systems Systems based on a common model
of network architecture and a suite of protocols used
in its implementation

15-91
Open Systems
• The International
Organization for
Standardization (ISO)
established the Open
Systems Interconnection
(OSI) Reference Model
• Each layer deals with a
particular aspect of
network communication
Figure 15.5 The layers of the OSI Reference Model

15-92
Network Protocols
• Network protocols are layered such that each
one relies on the protocols that underlie it
• Sometimes referred to as a protocol stack
Figure 15.6 Layering of key network protocols

15-93
TCP/IP
• TCP stands for Transmission Control Protocol
TCP software breaks messages into packets, hands
them off to the IP software for delivery, and then
orders and reassembles the packets at their
destination
• IP stands for Internet Protocol
IP software deals with the routing of packets
through the maze of interconnected networks to
their final destination

15-94
TCP/IP (cont.)
• UDP stands for User Datagram Protocol
– It is an alternative to TCP
– The main difference is that TCP is highly reliable,
at the cost of decreased performance, while UDP
is less reliable, but generally faster

Computer Applications

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Computer Applications

Similar to Computer Applications (20)

More from cpjcollege

More from cpjcollege (20)

Recently uploaded

Recently uploaded (20)

Computer Applications