Lead Black Slide

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Chapter 5

Information System Software

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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

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