E. Wainright Martin Carol V. Brown Daniel W. DeHayes Jeffrey A. Hoffer William C. Perkins MANAGINGINFORMATIONTECHNOLOGY FIFTH EDITION CHAPTER 9 (part a) B ASIC I NFORMATION S YSTEMS C ONCEPTS

© 2005 Pearson Prentice-Hall Chapter T HE S YSTEMS V IEW Systems thinking is:  a discipline for seeing wholes  a framework for seeing interrelationships rather than things  an antidote to feeling of helplessness when dealing with complexity Page 355 Peter Senge (1990)

© 2005 Pearson Prentice-Hall Chapter Page 355 System – a set of interrelated components that must work together to achieve some common purpose T HE S YSTEMS V IEW What Is a System?

© 2005 Pearson Prentice-Hall Chapter Page 355 T HE S YSTEMS V IEW All components are there … but they don’t work well together! Figure 9.1 An Example of Poor Design What Is a System?

© 2005 Pearson Prentice-Hall Chapter Page System – a set of interrelated components that must work together to achieve some common purpose T HE S YSTEMS V IEW What Is a System? Information System – the collection of IT, procedures, and people responsible for the capture, movement, management, and distribution of data and information

© 2005 Pearson Prentice-Hall Chapter Page 356 Seven Key System Elements T HE S YSTEMS V IEW 1. 1.Boundary 2. 2.Environment 3. 3.Inputs 4. 4.Outputs 5. 5.Components 6. 6.Interfaces 7. 7.Storage Figure 9.2 General Structure of a System

© 2005 Pearson Prentice-Hall Chapter Page 357 Figure 9.3 System Component Examples

© 2005 Pearson Prentice-Hall Chapter Page 357 Seven Key System Elements – System Boundary System boundary depends on: 1. What can be controlled 2. What scope is manageable within a given time period 3. The impact of a boundary change T HE S YSTEMS V IEW

© 2005 Pearson Prentice-Hall Chapter Page 357 Seven Key System Elements – Component Decomposition A component of a system is also called a subsystem or module Hierarchical decomposition – the process of breaking down a system into successive levels of subsystems, each showing more detail T HE S YSTEMS V IEW

© 2005 Pearson Prentice-Hall Chapter Page 357 Seven Key System Elements – Component Decomposition Goals of hierarchical decomposition: 1. To cope with system complexity 2. To analyze or change part of the system 3. To design and build each subsystem at different times 4. To direct the attention of a target audience 5. To allow system components to operate more independently T HE S YSTEMS V IEW

© 2005 Pearson Prentice-Hall Chapter Page Seven Key System Elements – Interfaces Functions of an interface:  Filtering  Coding/decoding  Error detection and correction  Buffer  Security  Summarizing Interface – point of contact between a system and its environment or between two subsystems T HE S YSTEMS V IEW

© 2005 Pearson Prentice-Hall Chapter Page 359 Seven Key System Elements – Interfaces Interfaces built between two preexisting systems are called bridges T HE S YSTEMS V IEW

© 2005 Pearson Prentice-Hall Chapter Page 359 Seven Key System Elements – Interfaces Possible objective of an interface:  System decoupling – changing two system components so that modifying one does not necessarily require modifying the other T HE S YSTEMS V IEW

© 2005 Pearson Prentice-Hall Chapter Page 358 Figure 9.4 Sales Summary Reporting System

© 2005 Pearson Prentice-Hall Chapter Page 359 Figure 9.4 Sales Summary Reporting Subsystem

© 2005 Pearson Prentice-Hall Chapter Page 359 Organizations as Systems Figure 9.5 Fundamental Components of an Organization How does a change in one affect the others? T HE S YSTEMS V IEW

© 2005 Pearson Prentice-Hall Chapter Page 360 Systems Analysis and Design Fundamental principles:   Choose an appropriate scope (boundary selection)   Logical before physical (what before how) Systems analysis and design (SA&D) – a process used in developing new information systems based on a systems approach to problem solving T HE S YSTEMS V IEW

© 2005 Pearson Prentice-Hall Chapter Page 360 Systems Analysis and Design Recommended problem-solving steps: Problem (or system) is a set of problems that must be broken down into smaller, more manageable problems Single solution is not always obvious to all – alternatives should be generated and considered Understanding of problem changes, so reassess commitment to solution at various stages T HE S YSTEMS V IEW

© 2005 Pearson Prentice-Hall Chapter Page 361 Business process – a set of work activities and resources B USINESS P ROCESSES

© 2005 Pearson Prentice-Hall Chapter Page 361 One way managers can evaluate a business process Figure 9.6 Evaluating Business Processes (Keen, 1997)

© 2005 Pearson Prentice-Hall Chapter Page 362 Business process reengineering (BPR) – radical business redesign initiatives that attempt to achieve dramatic improvements in business processes by questioning the assumptions, or business rules, that underlie the organization’s structures and procedures B USINESS P ROCESSES Business Process Redesign

© 2005 Pearson Prentice-Hall Chapter Page 363 B USINESS P ROCESSES Business Process Redesign Six principles for redesigning business processes: 1. 1.Organize business processes around outcomes, not tasks 2. 2.Assign those who use the output to perform the process 3. 3.Integrate information processing into the work that produces the information

© 2005 Pearson Prentice-Hall Chapter Page 362 B USINESS P ROCESSES Business Process Redesign Six principles for redesigning business processes: 4. 4.Create a virtual enterprise by treating geographically distributed resources as though they were centralized 5. 5.Link parallel activities instead of integrating their results 6. 6.Have the people who do the work make all the decisions, and let controls built into the system monitor the process

© 2005 Pearson Prentice-Hall Chapter Page 363 B USINESS P ROCESSES Business Process Redesign Figure 9.7 How IT Enables New Ways to Work

© 2005 Pearson Prentice-Hall Chapter Page 364 P ROCESSES AND T ECHNIQUES TO D ELIVER I NFORMATION S YSTEMS The Information Systems Life Cycle Figure 9.8 Generic Systems Life Cycle

© 2005 Pearson Prentice-Hall Chapter Page 364 Definition Phase: End user and systems analysts conduct analysis of current system and business processes Analysis is:   Process-oriented   Data-oriented Business case generated and solution chosen P ROCESSES AND T ECHNIQUES TO D ELIVER I NFORMATION S YSTEMS The Information Systems Life Cycle

© 2005 Pearson Prentice-Hall Chapter P ROCESSES AND T ECHNIQUES TO D ELIVER I NFORMATION S YSTEMS Page 364 Construction Phase: System designed, built, and tested System logically described, then physically Technology chosen Programs, inputs, and outputs designed Software programmed and tested User acceptance testing conducted The Information Systems Life Cycle

© 2005 Pearson Prentice-Hall Chapter P ROCESSES AND T ECHNIQUES TO D ELIVER I NFORMATION S YSTEMS Page 364 Implementation Phase: Business managers and IS professionals install new system Data and procedures from old system converted The Information Systems Life Cycle

© 2005 Pearson Prentice-Hall Chapter Page 365 System development methodology – framework consisting of guidelines, tools, and techniques for managing skills to address the business issue Consists of processes, tools, techniques for developing systems Prescribe who participates, roles, development stages and decision points, and formats for documentation P ROCESSES AND T ECHNIQUES TO D ELIVER I NFORMATION S YSTEMS Structured Techniques for Life Cycle Development

© 2005 Pearson Prentice-Hall Chapter Page 365 Structured Techniques for Life Cycle Development Structured techniques – tools to document system needs, requirements, functional features, dependencies, and design decisions Procedural-oriented   Most common   Include data-oriented, sequential, process-oriented activities Object-oriented   Newer approach   Often used for GUIs and multimedia applications P ROCESSES AND T ECHNIQUES TO D ELIVER I NFORMATION S YSTEMS

© 2005 Pearson Prentice-Hall Chapter Page 365 Procedural-Oriented Techniques Provides a baseline for the new system Includes both logical and physical models Figure 9.9 Three-Step Modeling Approach P ROCESSES AND T ECHNIQUES TO D ELIVER I NFORMATION S YSTEMS

© 2005 Pearson Prentice-Hall Chapter Page 365 Procedural-Oriented Techniques Critical appraisal of existing work processes to: Identify major subprocesses, entities, and interactions Separate processing from data flow Capture relationships between data elements Determine entities and processes within scope Figure 9.9 Three-Step Modeling Approach P ROCESSES AND T ECHNIQUES TO D ELIVER I NFORMATION S YSTEMS

© 2005 Pearson Prentice-Hall Chapter Page 365 Procedural-Oriented Techniques Conducted by IS specialists Maps logical requirements to available technology Figure 9.9 Three-Step Modeling Approach P ROCESSES AND T ECHNIQUES TO D ELIVER I NFORMATION S YSTEMS