CHAPTER 14.
COMPUTER
SOFTWARE
SOFTWARE
Detailed instructions to control computer operation. There are
two major types of software:
 System software: manages computer resources. Set of
instructions that serves primarily as an intermediary
between computer hardware and application programs.
Manipulates computer hardware resources.
 Application software: specific business application. A set
of computer instructions that provide more specific
functionality to a user. There are many different software
applications in organizations today. Manipulate data or text
to produce or provide information.
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Systems Software
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Class of programs that control and support the
computer system and its information-processing
activities.
Systems software programs support application
software by directing the basic functions of the
computer.
For example, when the computer is turned on, the
initialization program (a systems program) prepares
all devices for processing.
Operating Systems
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Integrated system of programs that
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Manages the operations of the CPU
Controls the input/output and storage resources and
activities of the computer system
Provides various support services as the computer
executes application programs
Operating Systems (continued)
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Performs four basic functions
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1: User interface: Provides a user interface
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Allows humans to communicate with the computer
2: Resource management
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Manages the hardware and networking resources of the
system
Virtual memory capability
Operating Systems (continued)
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3: File management
Controls the creation, deletion, and access of files of
data and programs
 Keeps track of the physical location of files
4:Task management
 Manages the accomplishment of the computing tasks of
end users
 Multitasking
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Multiprogramming
Timesharing
MULTIPROGRAMMING
PROGRAM 1
UNUSED MEMORY
MULTIPROGRAMMING
ENVIRONMENT
OPERATING SYSTEM
OPERATING SYSTEM
TRADITIONAL SINGLEPROGRAM SYSTEM
PROGRAM 1
PROGRAM 2
PROGRAM 3
UNUSED MEMORY
The management of two or more tasks, programs, running on the
computer system at the same time.
MULTITASKING
MULTIPROGRAMMING
ON A
SINGLE-USER SYSTEM
SUCH AS A
MICROCOMPUTER
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TIME SHARING
It is an extension of multiprogramming.
 In this mode, a number of users operate online with the
same CPU, but each uses a different input/output terminal.
 The programs of these users are placed into partitions in
primary storage.
 Execution of these programs rotates among all users,
occurring so rapidly that it appears to each user as though
he or she were the only using the computer.
Operating Systems (continued)
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Popular Operating Systems
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Windows
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95, 98, ME
NT
2000
XP
UNIX
Linux
Mac OS X
Types of Personal Application Software
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WORD PROCESSING
SPREADSHEETS
DATA MANAGEMENT
GRAPHICS
DESKTOP PUBLISHING
GROUPWARE
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Types of Personal Application
Software
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Spreadsheets: Used for business analysis, planning,
and modeling.
Computer spreadsheet software transforms a
computer screen into a ledger sheet, or grid, of coded
rows and columns.
They can be used for financial information, such as
income statements or cash flow analysis.
They are also used for forecasting sales, analyzing
insurance programs, summarizing income tax data,
and analyzing investments.
They also offer data management and graphical
capabilities. Ex: Ms Excel, Lotus 1-2-3.
Types of Personal Application
Software
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Data management: Data management software
supports the storage, retrieval, and
manipulation of related data.
Produce forms, reports, & other documents.
Add, delete, update, and correct the data
Ex: Ms-Access.
Types of Personal Application
Software
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Word processing: allows the user to manipulate text
rather than just numbers.
Many word processors contain many productive
writing and editing features.
A typical word processing software package consists
of an integrated set of programs including an editor
program, a formatting program, a print program, a
dictionary, a grammar checker, and integrated
graphics, charting, and drawing programs.
Types of Personal Application
Software
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Desktop publishing: represents a level of
sophisticated beyond regular word processing.
In the past, newsletters, announcements,
advertising copy had to be laid out by hand
and typeset.
Design and print newsletters, brochures,
manuals, and books.
Types of Personal Application
Software
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Graphics: Graphics software allow user to create,
store and display or print charts, graphs, maps and
drawings.
It enables users to absorb more information more
quickly and to spot relationships and trends in data
more easily.
Ex: Ms-Power Point (Helps convert numeric data into
graphic displays. Presentation graphics software)
Types of Personal Application
Software
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Groupware: it facilitates communication, coordination, and
collaboration among people.
Helps workgroups and teams work together to accomplish
group assignments.
Combines a variety of software features and functions
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E-mail
Discussion groups and databases
Scheduling
Task management
Audio and videoconferencing
Data sharing
Ex: Novell’s Group Wise, Oracle’s InterOffice.
Software Suits
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Suites are a number of productivity packages
bundled together
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Microsoft Office
Lotus SmartSuite
Corel WordPerfect Office
Sun StarOffice
Software Suites (continued)
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Advantages of suites
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Cost
Similar graphical user interface
Share common tools
Programs are designed to work together
Disadvantages of suites
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Large size
Many features never used by many end users
Web Browsers
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Key software interface to the hyperlinked
resources of the World Wide Web and the rest of
the Internet. Easy-to-use software tools for
displaying Web and the other Internet resources.
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Internet Explorer
Netscape Communicator
Programming Languages
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Programming languages allow people to tell
computers what to do and are the means by
which software systems are developed.
GENERATIONS OF PROGRAMMING
LANGUAGES
1st. Since 1940s. MACHINE LANGUAGE:
binary code
2nd. Since early ’50s. ASSEMBLER
LANGUAGE: mnemonics for numeric
code
3rd. Since mid ‘50s. HIGH-LEVEL
LANGUAGES
4th. Since late ‘70s. FOURTHGENERATION LANGUAGES
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Machine language
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Lowest-level computer language.
It is considered the first-generation language.
Composed of binary codes unique to each computer
Requires the programmer to write all program
instructions in the 0s and 1s of binary code.
It is extremely difficult to understand, and use by
programmers. Very slow.
As a result, increasingly more user-friendly languages
have been developed.
Assembler language
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Next level up from machine language.
It is still considered a lower-level language but
is more user-friendly.
Requires language translator programs called
assemblers
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Allows a computer to convert the instructions into
machine instructions
Frequently called symbolic language
High-level languages
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Third generation
Uses instructions, called statements, that use brief
statements or arithmetic expressions
Uses translator programs called compilers or
interpreters
Syntax and semantics
HIGH-LEVEL LANGUAGES
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FORTRAN (FORmula TRANslator):
Scientific, Engineering applications
COBOL (COmmon Business Oriented
Language): Predominant for transaction
processing
BASIC (Beginners All-purpose Symbolic
Instruction Code): General purpose PC
language
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HIGH-LEVEL LANGUAGES
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PASCAL: Used to teach structured programming
practices. Weak in file handling, input / output
C: Powerful PC Language for developing
applications. Efficient execution; cross platform.
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FOURTH GENERATION LANGUAGES
(4GL)
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Can be used by non-technical users to carry
out specific functional tasks.
Called NONPROCEDURAL.
Can develop applications quickly
These languages greatly simplify and
accelerate the programming process.
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FOURTH GENERATION LANGUAGES (4GL)
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Examples of the 4GLs are query languages
(SQL), report generators (RPG III), graphics
languages (Visual C++) and PC software tools
(WordPerfect, Ms-Access).
Object-oriented programming
languages
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Based on the idea of taking a small amount of data
and the instructions about what to do with that data
and putting both of them together into what is called
an object.
Easier to use.
Creates reusable code.
Reduces time and cost of writing software.
OBJECT-ORIENTED
PROGRAMMING
JAVA: Sun Microsystems OBJECT-ORIENTED
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PROGRAMMING LANGUAGE
Applet: tiny program to execute small function
Applets downloaded from network
Run on any computer & operating system
Designed for real-time, interactive, Web-based network
applications
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OBJECT-ORIENTED PROGRAMMING
HTML (Hypertext Markup Language)
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A page description language that creates hypertext or
hypermedia documents
HTML is very easy to use.
The standard language the World Wide Web uses for creating
and recognizing hypertext documents.