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Lead Black Slide
© 2001 Business & Information Systems 2/e
2
Chapter 5
Information System Software
© 2001 Business & Information Systems 2/e
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Our Agenda Software Concepts Application Software System Software Software Development
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Learning Objectives 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.) Explain the main differences between
the five types, or generations, of programming languages.
Explain the difference between object-oriented programming and traditional programming, and identify one traditional and one object-oriented programming language.
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Learning Objectives (cont’d.) 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 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 Word processing Spreadsheet Graphics Database Browser
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Workgroup Application Software Groupware E-Mail software Information sharing software Electronic conferencing software
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Other Application Software Organizational application software
Generally organization specific Interorganizational application
software 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 An operating system is a group of
programs that manages the operation of the computer.
Three functions of an operating system Process management Resource management Data management
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Operating System Concepts (cont’d.) Organization of an operating system
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 Starting the computer is called booting
which transfers the “supervisor” from secondary storage to primary storage.
Connecting to a network or other multi-user environment is called logging in.
Detaching from a network is called logging out.
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Elements of an Operating System User interface is the visual link
between the user and the software. Small pictures on the screen are
icons. Graphical User Interface (GUI) uses
Buttons Icons Menus Dialog boxes
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Capabilities of Operating Systems 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.) 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.) Two types of operating systems
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.) 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.) 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 Microsoft Windows Microsoft DOS (and others) IBM OS/2 Apple Mac OS UNIX Linux
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Multi-User Computer Common Operating Systems IBM OS/390 Hewlett Packard MPE
(MultiProgramming Executive) UNIX Network Operating Systems
Novell Netware Windows 2000 Server
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Other System Software Utility programs
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.) 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 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
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 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
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 First Generation Languages Second Generation Languages Third Generation Languages Fourth Generation Languages Fifth Generation Languages
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First Generation Languages
Machine language 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
Assembly languages 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
Closer to English but included simple mathematical notation. 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.)
Alternative to compilation is interpretation which is accomplished by a system program called an interpreter.
Common third generation languages FORTRAN COBOL C and C++ Visual Basic
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Fourth Generation Languages A high level language (4GL) that
requires fewer instructions to accomplish than a third generation language.
Used with databases Query languages Report generators Forms designers Application generators
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Fifth Generation Languages 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 Two broad groups
Traditional programming languages Sequences of instructions First, second and some third generation
languages Object-oriented languages
Objects are created rather than sequences of instructions
Some third generation, and fourth and fifth generation languages
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Traditional Programming Languages FORTRAN
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.) COBOL
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.) BASIC
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.) C
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 Smalltalk
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.) C++
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 HTML
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.) XML
Extensible Markup Language. A language for defining other
languages.
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Special Programming Languages (cont’d.) JAVA
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 Assembler Assembly Language BASIC Booting Browser Button C C++ COBOL
Command Compiler Database Software Dialog Box Electronic
Conferencing Software
Electronic Messaging Software
FORTRAN
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Key Terms (cont’d.) Fourth-Generation
Language (4GL) Graphical User
Interface (GUI) Graphics Software Groupware HTML Icon
Information Sharing Software
Interpreter Java Menu Multitasking Network Operating
System (NOS) Object
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Key Terms (cont’d.) Object-Oriented
Programming Operating Environment Page Programmer Programming Programming
Language Prompt Spreadsheet Software
Time-Sharing User Interface Utility Program Virtual Memory Window Word Processing
Software XML
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Summary Software Concepts Application Software System Software Software Development
Final Black Slide