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11 Jan 2011

11 Jan 2011. Systems Development Life Cycle ( SDLC ). http://www.aonghussugrue.wordpress.com. Resits for Christmas MCQ. This coming Friday 14th Jan at 10am. Venue room 3.85 (3rd floor o'Rahilly Builiding). This slide is from notes in first term. Overview of Systems Development.

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11 Jan 2011

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  1. 11 Jan 2011 Systems Development Life Cycle (SDLC) http://www.aonghussugrue.wordpress.com

  2. Resits for Christmas MCQ This coming Friday 14th Jan at 10am.Venue room 3.85 (3rd floor o'Rahilly Builiding).

  3. This slide is from notes in first term Overview of Systems Development Summary of Systems Development Activities

  4. Systems Development Life Cycle (SDLC) • Many approaches to systems development • Sequential versus Iterative Development • Understanding the difference between these two approaches is essential • Traditional Approach – Waterfall Model

  5. Systems Development Life Cycle (SDLC) • Traditional Approach is sequential • Each phase of development is completed before the next phase begins • Waterfall Model is a common example of a sequential approach

  6. SDLC - Waterfall Model Initiation Investigation Analysis Design Implementation NO FEEDBACK!!!! Maintenance

  7. SDLC - Waterfall Model • What are the limitations of this approach? • This is now regarded as the “hard” systems approach because of its rigid demarcation between phases • Cannot correct defects from previous stages • No Feedback • Expensive – Spending long time in each phase

  8. Example • Existing System – Analysis stage • Extensive problem analysis and Requirements gathered • Move to next stage – Design stage • Create design based on previous analysis stage • What happens if something changes

  9. SDLC - Waterfall Model Initiation Investigation Analysis Design Implementation NO FEEDBACK!!!! Maintenance

  10. SDLC – Waterfall Model • Limitations of sequential approach has lead to the emergence of a more iterative approach • Iterative approach involves a more flexible approach allowing for the movement back and forth between stages of the lifecycle • What are the advantages of this?

  11. Iterative approach to SDLC • Advantages • Flexibility – allows for changing requirements • Feedback from different stages – refinement • Maintains communication between systems analyst and the technical team • Why is this communication important?

  12. Business People Systems Analyst Business Solution Gap Between Business and Technical Technical Solution Technical People

  13. Iterative Approach to SDLC • Phases are generally the same as the waterfall model • However, there can be several iterations back and forth between these phases • Essentially this is an incremental approach

  14. Initiation Investigation Analysis Design Implementation Maintenance

  15. Phase 1: Project Planning & Initiation • Project planning and initiation essential • Aims: To establish whether the project is feasible and to ensure that the project will be successful • Initiation team must be developed • Why?

  16. Phase 1: Project Planning & Initiation • Key Initiation Activity – Developing a project charter • Short document for both internal and external stakeholders of the project • Providing high level overview of project • Why do this? Remember – IS not just a technical issue!

  17. Phase 1: Project Planning & Initiation • Project Charter – typically contains: • Project title, start date, prj manager, contact info • Customer details – key stakeholders • Project timeline (projected) • Key stakeholders (internal and external) • Responsibilities • Project Objectives and Description • Assumptions

  18. Phase 1: Project Planning & Initiation • Activities of project planning • Project scope • Feasibility and alternative options • Creating project tasks • Deliverables – start time; completion; responsibilities • Resource Requirements • Project Constraints

  19. Phase 2: Investigation • Investigation of the functional requirements of the existing system (if it exists) and whether these requirements can be achieved • The requirements of the new system

  20. Phase 2: Investigation • Interviewing - Individuals and groups of users is usually the most helpful technique for establishing and verifying information • Questionnaires - Used where large amounts of information needs to be obtained from a large number of respondents or from remote locations • Observation - Can be a useful insight into existing work problems • Documentation – Analysing existing documents within the system

  21. Documentation Aids • An organisation chart showing the reporting structure of people in a company or department • Various Flowcharts, which help the analyst to trace the flow of documents in the department. It is possible to include in the flowchart the processes that are applied to each document. These processes could include for example the checking and error correction procedures.

  22. Documentation Aids • Discussion records on which the notes taken at interviews could be recorded. • Grid charts, showing how different components of the system such as people and machines interact with each other.

  23. End of Lecture Notes

  24. Tutorials • Low attendance in labs today • Attendance is mandatory – will be taken into account when correcting in-class exams and final year exams • Tutorial material in this term is extremely important!

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