1. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 1 Phased Development ► Phased development is an approach for developing information systems that consists of six stages:  Preliminary investigation  Analysis  Design  Preliminary construction  System test  Installation. ► Best suited for systems of all sizes.

2. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 2 Figure 7.8 Stages of Phases Development

3. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 3 Module Phases ► System is subdivided into major modules such as:  Report writer;  Database;  Web interface. ► Number of modules varies with the system from 1 to a dozen or so. ► Stages are performed separately for each module.

4. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 4 Figure 7.9 Module Phase of Systems Development

5. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 5 Business Process Redesign ► Reengineering or Business process redesign (BPR) is the process of reworking the systems.  Systems include both those that process the firm’s data & those that perform basic functions such as drilling for oil. ► BPR affects the firm’s IT operations in two ways:  Aids in the redesign of old information systems (legacy systems);  Applies to the redesign of information systems to support major operations. ► Usually initiated at strategic management level.

6. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 6 Figure 7.10 Top-Down Initiation of BPR Projects

7. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 7 Strategic Initiation of BPR ► Reverse engineering is the process of analyzing an existing system to:  identify its elements & their interrelationships;  Create documentation at a higher level of abstraction than currently exists. ► Functionality is the job that it performs. ► Reengineering is the complete redesign of a system with the objective of changing its functionality. ► Forward engineering is given to the process of following the SDLC in the normal manner while engaging in BPR.

8. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 8 BPR Components ► BPR components can be applied separately or in combination. ► Functional quality is a measure of what the system does. ► Technical quality is a measure of how well it does it.

9. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 9 Figure 7.11 BPR Component Selection

10. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 10 Methodologies in Perspective ► Traditional SDLC is an application of the systems approach to the problem of system development; contains all elements. ► Prototyping is an abbrev. form focusing on the definition & satisfaction of user needs. ► RAD is an alternative approach to the design & implementation phases of SDLC. ► Phased development uses traditional SDLC & applies it in a modular fashion.

11. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 11 System Development Tools ► Process modeling was first done with flowcharts.  ISO standards  Use of 20+ symbols ► Data flow diagrams (DFD) is a graphic representation of a system that uses four symbol shapes to illustrate how data flows through interconnected processes.. ► DFDs are excellent for modeling processes at a summary level.

12. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 12 Data Flow Diagram Symbols ► Terminator describes an environmental element, such as a person, organization, or another system.  Environmental elements exist outside the boundary of the system. ► Process is something than transforms input into output. ► Data flow consists of a group of logically related data elements that travel from one point or process to another; can diverge and converge. ► Data storage is a repository of data. ► Connector contains the number of the process that provides the data flow.

13. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 13 Figure 7.12 DFD of a Sales Commission System

14. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 14 Leveled Data Flow Diagrams ► Leveled DFDs is used to describe the hierarchy of diagrams, ranging from context to lowest-level n diagram. ► Figure 0 diagram identifies the major processes of a system.  Use additional DFDs to achieve documentation at both a more summarized & a more detailed level. ► Context diagram is a diagram that documents the system at a more summarized level.  Positions the system in a environmental context. ► Figure n diagram is a diagram that provides more detail.  n represents the # of processes on the next higher level.  Documents a single process of a DFD in greater detail.

15. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 15 Figure 7.13 Context Diagram of a Sales Commission System

16. © 2007 by Prentice HallManagement Information Systems, 10/e Raymond McLeod and George Schell 16 Figure 7.14 Figure 4 Diagram of a Sales Commission System