Principles of Information Systems, Seventh Edition2 When selecting an operating system, you must...

Principles of Information Systems, Seventh Edition 2

• When selecting an operating system, you must consider the current and future requirements for application software to meet the needs of the organization. In addition, your choice of a particular operating system must be consistent with your choice of hardware.

• Identify and briefly describe the functions of the two basic kinds of software

• Outline the role of the operating system and identify the features of several popular operating systems


• Do not develop proprietary application software unless doing so will meet a compelling business need that can provide a competitive advantage

• Discuss how application software can support personal, workgroup, and enterprise business objectives

• Identify three basic approaches to developing application software and discuss the pros and cons of each


• Choose a programming language whose functional characteristics are appropriate for the task at hand, taking into consideration the skills and experience of the programming staff

• Outline the overall evolution of programming languages and clearly differentiate among the five generations of programming languages


• The software industry continues to undergo constant change; users need to be aware of recent trends and issues to be effective in their business and personal life

• Identify several key issues and trends that have an impact on organizations and individuals


An Overview of Software

• Computer programs: sequences of instructions for the computer

• Documentation: describes program functions to help user operate computer system

• Systems software: set of programs that coordinates the activities of hardware and programs

• Application software: programs that help users solve particular problems


Table 4.1: Classifying Software by Type and Sphere of Influence


Systems Software: Operating Systems

• Operating system (OS): a set of computer programs that controls the computer hardware and acts as an interface with application programs

• Kernel: ties all of the components of the OS together and regulates other programs; controls the most critical processes


Operating Systems (continued)

• Activities performed by the operating system:

• Perform common computer hardware functions

• Provide a user interface and input/output management

• Provide a degree of hardware independence

• Manage system memory



• Activities performed by the operating system:

• Manage processing tasks

• Provide networking capability

• Control access to system resources

• Manage files


Figure 4.2: Operating system as interface between

application software and hardware



• Common hardware functions

• Get input from the keyboard or some other input device

• Retrieve data from disks

• Store data on disks

• Display information on a monitor or printer



• User interface and input/output management

• User interface: allows individuals to access and command the computer system

• Command-based user interface: requires that text commands be given to the computer to perform basic activities

• Graphical user interface (GUI): uses icons and menus displayed on screen to send commands to computer system



• Application program interface (API): allows applications to make use of the operating system

• Memory management: control how memory is accessed and maximize available memory and storage


Figure 4.3: Application Program Interface Links Application Software to the

Operating System


• Processing tasks

• Multitasking: capability allowing more than one program to run at the same time

• Time-sharing: allows more than one person to use a computer system at the same time

• Scalability: ability of the computer to handle an increasing number of concurrent users smoothly

• Networking capability: features and capabilities of the OS that aid users in connecting to a computer network




• Access to system resources

• Protection against unauthorized access

• Logins and passwords

• File management: ensures that files in secondary storage are available when needed and that they are protected from access by unauthorized users


Table 4.3: Popular Operating Systems Cross All Three Spheres of Influence


Current Operating Systems

• Microsoft PC operating systems

• Apple computer operating systems

• Linux


Workgroup Operating Systems

• Windows Server

• UNIX

• NetWare

• RedHat Linux

• Mac OS X Server


Enterprise Operating Systems

• z/OS

• MPE/iX and HP-UX

• Linux


Operating Systems for Small Computers and Special-Purpose Devices

• Palm OS

• Windows Embedded

• Windows Mobile


Utility Programs

• Utility programs are used to:

• Merge and sort sets of data

• Keep track of computer jobs being run

• Compress data files before they are stored or transmitted over a network

• Perform other important tasks


Utility Programs (continued)

• Hardware utilities

• Virus-detection and virus-recovery utilities

• File-compression utilities

• Spam and pop-up blocker utilities


Utility Programs (continued)

• Network and Internet utilities

• Server and mainframe utilities

• Other utilities


Table 4.4: Examples of Utility Programs


Application Software

• Primary function is to apply the power of the computer to give individuals, workgroups, and the entire enterprise the ability to solve problems and perform specific tasks

• Application programs interact with systems software; systems software then directs the computer hardware to perform the necessary tasks


Types and Functions of Application Software

• Proprietary software: a one-of-a-kind program for a specific application, usually developed and owned by a single company

• Off-the-shelf software: existing software programs that are purchased


Table 4.5: A Comparison of Proprietary and Off-the-Shelf Software


Table 4.5: A Comparison of Proprietary and Off-the-Shelf Software (continued)


Personal Application Software

• Serve the needs of an individual user

• Include personal productivity software, which enable users to improve their personal effectiveness


Table 4.6: Examples of Personal Productivity Software


Table 4.6: Examples of Personal Productivity Software (continued)


Workgroup Application Software

• Workgroup application software: designed to support teamwork, whether people are in the same location or dispersed around the world

• Groupware: software that helps groups of people work together more efficiently and effectively


Table 4.8: Ernst & Young’s “Three Cs” Rule for Groupware


Enterprise Application Software

• Software that benefits an entire organization

• Enterprise resource planning (ERP) software: a set of integrated programs that manage a company’s vital business operations for an entire multisite, global organization


Table 4.9: Examples of Enterprise Application Software


Programming Languages

• Programming languages: sets of keywords, symbols, and a system of rules for constructing statements

• Allow humans to communicate instructions to be executed by a computer

• Different languages have different characteristics

• Syntax: a set of rules associated with a programming language


Table 4.11: The Evolution of Programming Languages


First Generation

• Machine language

• Required use of binary symbols (0s and 1s)


Second Generation

• Assembly languages

• Use symbols rather than binary digits

• Assemblers: programs that translate assembly languages into machine code


Third Generation

• Greater use of symbolic code

• Examples: BASIC, COBOL, C, and FORTRAN

• Compiler: a software program that converts the programmer’s source code into the machine-language instructions consisting of binary digits


Figure 4.18: How a Compiler Works


Fourth Generation

• 4GLs: fourth-generation languages

• Easier to use, and more English-like, than third generation languages

• Programs tell the CPU the desired results, not how to get them

• Examples: SQL, SAS


Languages Beyond the Fourth Generation

• Artificial intelligence, visual, and object-oriented languages

• Easier for nonprogrammers to use

• Programming languages used to create artificial intelligence or expert systems applications are called fifth-generation languages (5GLs)

• Visual languages use a graphical or visual interface for program development

• Object-oriented programming languages are based on objects (data and the actions that can be performed on it)


Software Issues and Trends

• Software bugs: defects in a computer program that keep it from performing in the manner intended

• Copyrights and licenses

• Open-source software: software that is freely available to anyone in a form that can be easily modified


Software Issues and Trends (continued)

• Shareware and freeware: software that is very inexpensive or free, but whose source code cannot be modified

• Multiorganizational software development

• Software upgrades

• Global software support


Summary

• Computer programs: sequences of instructions for the computer

• Systems software: coordinates the activities of hardware and programs

• Applications software: helps users solve particular problems

• Operating system (OS): a set of computer programs that controls the computer hardware and acts as an interface with application programs


Summary (continued)

• Graphical user interface (GUI): a user interface that uses icons and menus displayed on screen to send commands to the computer system

• Time-sharing allows more than one person to use a computer system at the same time

• Proprietary software: a one-of-a-kind program designed for a specific application, usually developed and owned by a single company

• Off-the-shelf software: existing software program that is purchased


Summary (continued)

• Enterprise resource planning (ERP) software: manages a company’s vital business operations for an entire multisite, global organization

• Programming languages allow humans to communicate instructions to be executed by a computer

• Programming languages can be classified as first generation, second generation, third generation, fourth generation, and languages beyond the fourth generation

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