Systems And Application Software

• 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 Principles of Information Systems, Seventh Edition

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• 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

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• 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 Principles of Information Systems, Seventh Edition

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• 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

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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 Principles of Information Systems, Seventh Edition

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Table 4.1: Classifying Software by Type and Sphere of Influence

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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

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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

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Operating Systems (continued) • Activities performed by the operating system: • Manage processing tasks • Provide networking capability • Control access to system resources • Manage files

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Figure 4.2: Operating system as interface between application software and hardware

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Operating Systems (continued) • 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

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Operating Systems (continued) • 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

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Operating Systems (continued) • 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

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Figure 4.3: Application Program Interface Links Application Software to the Operating System

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Operating Systems (continued) • 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

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Operating Systems (continued) • 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

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

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Current Operating Systems • Microsoft PC operating systems • Apple computer operating systems • Linux

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Workgroup Operating Systems • Windows Server • UNIX • NetWare • RedHat Linux • Mac OS X Server

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Enterprise Operating Systems • z/OS • MPE/iX and HP-UX • Linux

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Operating Systems for Small Computers and Special-Purpose Devices • Palm OS • Windows Embedded • Windows Mobile

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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

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Utility Programs (continued) • Hardware utilities • Virus-detection and virus-recovery utilities • File-compression utilities • Spam and pop-up blocker utilities

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Utility Programs (continued) • Network and Internet utilities • Server and mainframe utilities • Other utilities

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Table 4.4: Examples of Utility Programs

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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

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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

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

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

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Personal Application Software • Serve the needs of an individual user • Include personal productivity software, which enable users to improve their personal effectiveness

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Table 4.6: Examples of Personal Productivity Software

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Table 4.6: Examples of Personal Productivity Software (continued)

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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

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

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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

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Table 4.9: Examples of Enterprise Application Software

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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 Principles of Information Systems, Seventh Edition

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Table 4.11: The Evolution of Programming Languages

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First Generation • Machine language • Required use of binary symbols (0s and 1s)

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Second Generation • Assembly languages • Use symbols rather than binary digits • Assemblers: programs that translate assembly languages into machine code

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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

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Figure 4.18: How a Compiler Works

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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

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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)

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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

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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

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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 Principles of Information Systems, Seventh Edition

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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 Principles of Information Systems, Seventh Edition

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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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