ch4 software

Information System for Managers

Chapter 4 - Software: Systems and Application Software

CONTENT

Why Learn about S/WIntroductionSystem Software

Operating System Utility Programs Middleware and Others

Application SoftwareProgramming LanguagesOpen Source Software

Why Learn About Software?

Systems & application S/W are critical in helping individuals & organizations achieve their goals

Decide – Build or BuyChoose appropriate software platform

considering the skills and experienceNeed to be aware of recent trends and issues to

be effective in business and personal life

Introduction

Systems software: coordinates the activities and functions of hardware and programs

Computer system platform: combination of a hardware configuration and systems software

Application software: helps users solve particular problems

Computer programs: sequences of instructions for the computer

Documentation: describes program functions

Systems Software

Operating systemsUtility programsMiddleware and Others

Operating Systems (continued)

Combinations of OSs, computers, and users Single computer with a single user, e.g. PC Single computer with multiple users, e.g. Main Frame

computer where hundreds of users are working Multiple computers, e.g. network of computers Special-purpose computers, e.g. home appliances

Operating Systems (continued)

OS is set of programsActivities 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 Manage processing tasks Provide networking capability Control access to system resources Manage files

Operating Systems (continued)

Figure 4.4: The Role of Systems Software

Operating Systems (continued)

Common hardware functions Get input from keyboard or some other input device Retrieve data from disks Store data on disks Display information on a monitor or printer

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 the computer system

Operating Systems (continued)

Hardware independence Application program interface (API): allows

applications to make use of the operating system If hardware changes, application software need not

change

Memory management Control how memory is allocated, accessed and

maximize available memory and storage Physical Memory vs. Virtual Memory

Operating Systems (continued)

Figure 4.6: Application Program Interface Links Application Software to the Operating System

Processing tasks Multitasking: more than one program can 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

Operating Systems (continued)

Operating Systems (continued)

Access to system resources and security 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

Current OS

Table 4.2: Popular Operating Systems Cross All Three Spheres of Influence

Current OS (cont)

Microsoft PC operating systems PC-DOS and MS-DOS: early, command-driven OSs Windows XP: greatly improved stability and security

over previous versions of Windows Windows XP Professional X64: for computers with

newer 64-bit capabilities Vista: latest version of Windows Which is the new OS already announced?

Current OS (cont)

Apple operating systems Often provide cutting edge tools in graphics and

music not available from Microsoft Mac OS X

Jaguar (OS X.2) Panther (OS X.3) Tiger (OS X.4): support for 64-bit computing,

Dashboard, Spotlight, etc.

Current OS (cont)

Linux Developed by Linus Torvalds in 1991 Open-source product Only the kernel of an OS Several distributions available with

capabilities/applications that form a complete OS Examples: Red Hat Linux, Caldera OpenLinux

Workgroup Operating Systems

Windows ServerUNIXNetWareRed Hat LinuxMac OS X Server

Enterprise Operating Systems

z/OSMPE/iXHP-UXLinux

Operating Systems for Small Computers, Embedded Computers,

and Special-Purpose Devices

Palm OSWindows EmbeddedWindows Mobile

Utility Programs

Hardware utilities: i.e. check status of Hard DiskVirus-detection and recovery utilitiesFile-compression utilitiesSpam and pop-up blocker utilitiesNetwork and Internet utilitiesServer and mainframe utilities

Monitor network Virtual Machine – Multiple OS on same machine

Other utilities, e.g. Searches for files and documents

Middleware and Others

Middleware: Software that allows different applications to communicate & exchange data.

WEB Server (e.g. Apache)Application Server (WEBSphere)Transaction Server (Tuxedo)RDBMS (SQL Server 2005)CompilersInterpreters

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, e.g.

Railway Reservation ATM Pay Roll

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

Overview of Application Software

Proprietary software: one-of-a-kind program for a specific application, usually developed and owned by a single company, e.g. Pay Roll for Krune Computer Consultancy

Off-the-shelf software: existing software program that is purchased, e.g. Tally

Overview of Application Software (continued)

Table 4.4: A Comparison of Proprietary and Off-the-Shelf Software

Overview of Application Software (continued)

Table 4.4: A Comparison of Proprietary and Off-the-Shelf Software (continued)

Personal Application Software

Serves the needs of an individual userIncludes personal productivity software

Enables users to improve their personal effectiveness

Personal Application Software (continued)

Table 4.5: Examples of Personal Productivity Software

Personal Application Software (continued)

Table 4.5: Examples of Personal Productivity Software (continued)

Personal Application Software (continued)

Software suite: collection of single application programs packaged in a bundle

Microsoft Office: most popular general-purpose software suite

Other general-purpose software suites: Corel’s WordPerfect Office, Lotus SmartSuite, Sun Microsystems’s StarOffice

Integrated application packages: offer a range of capabilities for less money than software suites

Example: Microsoft Works

Personal Application Software (continued)

Table 4.6: Major Components of Leading Software Suites

Workgroup Application Software

Workgroup application software: support teamwork, whether people are in the same

location or dispersed around the world Helps groups of people work together more efficiently

and effectivelyExamples Schedule Team Meetings – reflects on individual

calendar Collaborative software for working on same

document, e.g. Track Change Threaded group discussion

Enterprise Application Software

Software that benefits an entire organization

Enterprise Application Software

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

Specialized Application Software Forecasting sale for next month Predicting which customer is more likely to buy Which items in supermarket sell together Visualize and analyze the human genome

Programming Languages

Sets of keywords, symbols, and a system of rules for constructing statements by which humans can communicate instructions to be executed by a computer

Different languages have different characteristics

Syntax: a set of rules associated with a programming language

The Evolution of Programming Languages

3G Example – C, COBOL, FORTRAN Table 4.9: The Evolution of Programming Languages

3GL Vs 4GL

3GL Tells how to do More Efficient More flexible

4GL Tells what to do (How part left on system) Higher productivity

Embedding 4GL in 3GL – Best of both worlds3GL Object oriented programming languages

are based on objects, e.g. C++, Java

The Evolution of Programming Languages (continued)

Figure 4.21: Reusable Code in Object-Oriented Programming

Complier and Interpreter

Compiler: a special software program that converts programmer’s source code into machine-language program

Interpreter: a special software program that converts programmer’s instruction (One at a time) into machine-language instructions and executes them

The Evolution of Programming Languages (continued)

Figure 4.23: How a Compiler Works

Software Issues and Trends

Because software is such an important part of today’s computer systems, software issues have received increased attention

Major software issues and trends discussed in the text

Software bugs, copyright, software licensing, open-source software, shareware and public domain software, multiorganizational software development, software upgrades, and global software support

Software Issues and Trends (Cont)

Software bug: defect in a computer program that keeps it from performing as it is designed to perform

Most software products are protected by law using copyright or licensing provisions

In some cases, you are given unlimited use of software on one or two computers

In other cases, you pay for your usage—if you use the software more, you pay more

Some software now requires that you register or activate it before it can be fully used

Open-Source Software

Open-source software: software freely available to anyone in a form that can

be easily modified (System Software, Utility or Application Software)

Some widely used open-source software: Linux OS, Free BSD, Apache, Sendmail, Perl

Open-source software disadvantages systems can contain hidden costs, particularly for

user support or solving problems with the software However community or paid third party support made

available

Open-Source Software (continued)

Table 4.10: Examples of Open-Source Software

Shareware, Freeware, and Public Domain Software

Shareware and freeware: Software that is very inexpensive or free Source code cannot be modified Source code may not be available (Acrobat Reader)

Public domain software: Shareware and freeware that is in the public domain Not protected by copyright law Can be freely copied and used May not be open source

Open Source Source is available

Software Upgrades

Software companies revise their programs and sell new versions periodically

Revised software may or may not offer any major additional capabilities

Revised software may have patches for bugsRevised software can contain bugs or errors

Users should not be first to work at the latest version Who should be first?

Software upgrades usually cost much less than the original purchase price

Global Software Support

Vendors face the challenge of providing adequate support for their software customers in all locations of the world

Trend of outsourcing global support to one or more third-party distributors