Transcript Chapter 5

Lead Black Slide
Chapter 5
Information System Software
© 2001 Business & Information Systems 2/e
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Our Agenda
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Software Concepts
Application Software
System Software
Software Development
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Learning Objectives
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Explain in detail what programs and
software are.
Identify the common application
software used in information systems.
Describe some ways users can tell an
operating system what to do.
Describe some of the capabilities of
operating systems.
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Learning Objectives (cont’d.)
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Explain the main differences between
the five types, or generations, of
programming languages.
Explain the difference between objectoriented programming and traditional
programming, and identify one
traditional and one object-oriented
programming language.
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Learning Objectives (cont’d.)
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Identify programming languages that
are used with the Internet and the
World Wide Web.
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Software Concepts
Information System Software
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Software Concepts
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A program is a set of instructions that tells
the computer what to do.
Software can be a single program or a group
of programs needed to perform several
functions.
Simple programs may have a few hundred
instructions (lines of code) though most have
many more (several million).
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Application Software
Information System Software
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Individual Application
Software
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Word processing
Spreadsheet
Graphics
Database
Browser
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Workgroup Application
Software
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Groupware
E-Mail software
Information sharing software
Electronic conferencing software
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Other Application Software
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Organizational application software
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Generally organization specific
Interorganizational application software
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Electronic Data Interchange (EDI)
Generally common to the participating
organizations
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System Software
Information System Software
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Operating System Concepts
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An operating system is a group of
programs that manages the operation
of the computer.
Three functions of an operating system
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Process management
Resource management
Data management
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Operating System Concepts
(cont’d.)
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Organization of an operating system
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Most operating system programs are
stored in secondary storage.
One operating system program is stored in
a section of primary storage. It goes by
various names – kernel – but generically
called the “supervisor”.
The supervisor controls all activity in
primary storage.
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Using an Operating System
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Starting the computer is called booting
which transfers the “supervisor” from
secondary storage to primary storage.
Connecting to a network or other multiuser environment is called logging in.
Detaching from a network is called
logging out.
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Elements of an Operating
System
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User interface is the visual link between
the user and the software.
Small pictures on the screen are icons.
Graphical User Interface (GUI) uses
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Buttons
Icons
Menus
Dialog boxes
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Capabilities of Operating
Systems
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Multitasking is appearing to execute
more than one program at a time,
though the CPU can execute
instructions from only one program at a
time.
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Capabilities of Operating
Systems (cont’d.)
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Multi-user or Multiple-user programs
permit more than one person to use the
program, and data, at a time.
One technique that is used with
multiple-user operating systems is time
sharing. With this technique, the users
are each allocated a small amount of
time by the operating system.
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Capabilities of Operating
Systems (cont’d.)
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Two types of operating systems
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Batch operating systems where the first
program is executed and all data processed
before moving to the second program.
Interactive operating systems allow user
interaction as the program executes. Most
personal computer operating systems
permit user interaction.
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Capabilities of Operating
Systems (cont’d.)
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Virtual memory is supplemental primary
storage (RAM) or “real” memory where
the programs are too big for primary
storage. It is created on a secondary
storage device, usually the hard drive,
and is generally temporary in nature.
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Capabilities of Operating
Systems (cont’d.)
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Virtual memory operating systems
execute large programs by dividing the
program into parts and transferring the
necessary parts of the program from
secondary storage to primary storage as
needed.
The transfer process does not require
any action by the user.
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Personal Computer Common
Operating Systems
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Microsoft Windows
Microsoft DOS (and others)
IBM OS/2
Apple Mac OS
UNIX
Linux
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Multi-User Computer Common
Operating Systems
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IBM OS/390
Hewlett Packard MPE
(MultiProgramming Executive)
UNIX
Network Operating Systems
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Novell Netware
Windows 2000 Server
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Other System Software
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Utility programs
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Sort utility – rearranges data in a specified
order
Merge utility – merges two files into one
Print utility – prints the contents of a file
Copy utility – copies data from one device
to another
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Other System Software
(cont’d.)
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Communications software – used for
communications between computers.
Database management systems – used
for managing databases.
Software development software –
software used to develop software.
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Software Development
Information System Software
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Programming Language
Concepts
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What is a programming language?
Why are there so many programming
languages?
How do you select a programming
language?
What are the types of programming
languages?
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What is a Programming
Language
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English is a natural language. It has
words, symbols and grammatical rules.
A programming language also has
words, symbols and rules of grammar.
The grammatical rules are called syntax.
Each programming language has a
different set of syntax rules.
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Why Are There So Many
Programming Languages
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Programming languages have evolved
over time as better ways have been
developed to design them.
Different programming languages are
designed for different types of
programs.
First programs were developed in the
1950s.
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How Do You Select a
Programming Language
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Is it designed for the type of program that
needs to be written?
Is it available on the computer being used?
Are trained programmers available?
Is it easy to write programs in the
language?
Is the language efficient when the program
is executed?
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What Are the Types of
Programming Languages
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First Generation Languages
Second Generation Languages
Third Generation Languages
Fourth Generation Languages
Fifth Generation Languages
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First Generation Languages
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Machine language
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Operation code – such as addition or
subtraction.
Operands – that identify the data to be
processed.
Machine language is machine dependent as it
is the only language the computer can
understand.
Very efficient code but very difficult to write.
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Second Generation Languages
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Assembly languages
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Symbolic operation codes replaced binary
operation codes.
Assembly language programs needed to be
“assembled” for execution by the computer.
Each assembly language instruction is
translated into one machine language
instruction.
Very efficient code and easier to write.
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Third Generation Languages
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Closer to English but included simple
mathematical notation.
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Programs written in source code which must
be translated into machine language
programs called object code.
The translation of source code to object code
is accomplished by a machine language
system program called a compiler.
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Third Generation Languages
(cont’d.)
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Alternative to compilation is interpretation
which is accomplished by a system
program called an interpreter.
Common third generation languages
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FORTRAN
COBOL
C and C++
Visual Basic
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Fourth Generation Languages
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A high level language (4GL) that requires
fewer instructions to accomplish than a third
generation language.
Used with databases
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Query languages
Report generators
Forms designers
Application generators
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Fifth Generation Languages
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Though no clear definition at present,
natural language programs generally
can be interpreted and executed by the
computer with no other action by the
user than stating their question.
Limited capabilities at present.
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Programming Languages
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Two broad groups
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Traditional programming languages
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Sequences of instructions
First, second and some third generation
languages
Object-oriented languages
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Objects are created rather than sequences of
instructions
Some third generation, and fourth and fifth
generation languages
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Traditional Programming
Languages
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FORTRAN
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FORmula TRANslation.
Developed at IBM in the mid-1950s.
Designed for scientific and mathematical
applications by scientists and engineers.
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Traditional Programming
Languages (cont’d.)
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COBOL
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COmmon Business Oriented Language.
Developed in 1959.
Designed to be common to many different
computers.
Typically used for business applications.
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Traditional Programming
Languages (cont’d.)
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BASIC
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Beginner’s All-purpose Symbolic Instruction
Code.
Developed at Dartmouth College in mid
1960s.
Developed as a simple language for
students to write programs with which they
could interact through terminals.
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Traditional Programming
Languages (cont’d.)
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C
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Developed by Bell Laboratories in the early
1970s.
Provides control and efficiency of assembly
language while having third generation
language features.
Often used for system programs.
UNIX is written in C.
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Object-Oriented Programming
Languages
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Smalltalk
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First object-oriented language.
Developed by Xerox in mid-1970s.
Still in use on some computers.
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Object-Oriented Programming
Languages (cont’d.)
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C++
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It is C language with additional features.
Widely used for developing system and
application software.
Graphical user interfaces can be developed
easily with visual programming tools.
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Special Programming
Languages
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HTML
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HyperText Markup Language.
Used on the Internet and the World Wide
Web (WWW).
Web page developer puts brief codes called
tags in the page to indicate how the page
should be formatted.
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Special Programming
Languages (cont’d.)
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XML
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Extensible Markup Language.
A language for defining other languages.
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Special Programming
Languages (cont’d.)
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JAVA
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An object-oriented language similar to C++
that allows a web page developer to create
programs for applications, called applets
that can be used through a browser.
Objective of JAVA developers is that it be
machine, platform and operating system
independent.
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Information Systems
Software
Key Terms
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Key Terms
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Assembler
Assembly Language
BASIC
Booting
Browser
Button
C
C++
COBOL
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Command
Compiler
Database Software
Dialog Box
Electronic Conferencing
Software
Electronic Messaging
Software
FORTRAN
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Key Terms (cont’d.)
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Fourth-Generation
Language (4GL)
Graphical User Interface
(GUI)
Graphics Software
Groupware
HTML
Icon
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© 2001 Business & Information Systems 2/e
Information Sharing
Software
Interpreter
Java
Menu
Multitasking
Network Operating
System (NOS)
Object
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Key Terms (cont’d.)
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Object-Oriented
Programming
Operating Environment
Page
Programmer
Programming
Programming Language
Prompt
Spreadsheet Software
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Time-Sharing
User Interface
Utility Program
Virtual Memory
Window
Word Processing
Software
XML
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Summary
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Software Concepts
Application Software
System Software
Software Development
© 2001 Business & Information Systems 2/e
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Final Black Slide