1. SDLC: System Development Life Cycle
Dr. Dania Bilal
IS 582
Spring 2008

2. Systems Analysis & Design
Method used to create and maintain systems that perform specific functions.
Examples: processing orders, employee payroll, acquisitions, cataloging, etc.
Use of application software designed to help employees to complete these functions

3. Application Software
Developed internally: in businesses & other organizations
Developed externally: by specific companies
Off-the-shelf application software may not fit the needs of all organizations

4. Components of IS Application
System software
Application software
Hardware
Documentation & training manuals
People who use the system
Technical personnel
People who keep system operating; trouble shooters
Controls/security
Prevent fraud and theft

5. Software Engineering Process
Components
Methodologies
Techniques
Tools

6. Methodologies
Approaches taken by system developers to develop the information system
Qualitative (e.g., interviewing users)
Quantitative (e.g., collect data via direct observations of users)

7. Techniques Based on methodology chosen
Qualitative vs. quantitative or both
Processes or procedures followed to gather data about current and/or potential users
Design interviews, observations, focus groups

8. IS Tools Computer-aided software engineering (CASE)
Used to develop the software
Draw diagrams, models, relationships among tasks, etc.

9. System Concepts
Decomposition
Modularity
Coupling
Cohesion

10. Decomposition
Process of breaking down a system into subsystems or smaller components
Smaller components may be broken down into small parts

11. Modularity A result of decomposition Divides system into modules
Makes system easier to understand, design/redesign, build/rebuild

12. Coupling
The degree subsystems or modules are dependent on each other in terms of operation (physically separate)
Subsystems should be as independent as possible
If one module fails, the other modules remain in operation

13. Cohesion
“The extent to which a system or subsystem performs a single function.”
Examples:
Check-in
Check-out

14. Important Concepts Data Information Database Data flow
Processing logic
Process-oriented approach to SD
Data-oriented approach to SD

15. Systems Development Life Cycle
(Valacich, George, & Hoffer, 2006)

16. Phase 1: Planning & Selection
Product identification and selection
Product initiation and planning
Identify potential development projects
Classify and rank projects
Select projects for development

17. Phase 2: Systems Analysis
Determine system requirements
Select appropriate methods to elicit system requirements from users of system
Interviews, focus groups, surveys, discussions, or other techniques

18. Phase 3: Systems Design Structure system requirements
Modeling processes
Develop data flow diagrams (DFDs) based on specific rules and guidelines that lead to accurate and well-structured process models.
Use DFDs to support analysis of IS

19. Phase 3: Systems Design
Use modeling and/or other techniques to represent data
Process modeling – based on specifications
Conceptual data modeling – user oriented
Select best alternative design strategy using both qualitative and quantitative methods

20. Phase 3: Systems Design Design the human interface
Design the interaction (dialogue)
Build a prototype
Perform usability testing
Design the database

21. Phase 4: System Implementation & Operation
Implement system:
Design specifications are turned into working computer code
Test code for errors and other problems
Use a sample data set

22. Phase 4: System Implementation & Operation
Install system
Prepare documentation
Train users of the system
Provide support
Maintain system on a regular basis

23. Class Activity Work in groups Examine the SDLC
Assess how the SDLC may apply to purchasing a product of your choice. This can be a house, car, computer, etc.