Stage 2 Design (System Life Cycle)
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The document outlines the stages of the design process, specifically focusing on preliminary and detail design phases. Key aspects include decisions on centralized vs. distributed systems, input capture methods, make-or-buy decisions, and the creation of prototypes. It emphasizes the importance of requirements specifications, system controls, and obtaining management authorization for proceeding with implementations.
Stage 2 Design (System Life Cycle)
- 3. DESIGN
- 4. PRELIMINARY DESIGN Major system aspects Centralized or distributed Online or batch PC-based? How will input be captured? Necessary reports
- 5. PRELIMINARY DESIGN Make or buy decision Packaged software Meet at least 75% of requirements? Change business procedures for part or all of remainder? Customize for part of all of remainder? Custom software Programmers write code Outsourcing System is developed by external organization
- 6. Create an overall plan Offer alternatives that meet requirements Explain differences Evaluate costs PRELIMINARY DESIGN
- 7. Build a prototype Limited working system of subset Does not need true functionality Output looks like anticipated system output Working model that can be modified and fine- tuned Uses high-level software tools – CASE Best for small-scale systems PRELIMINARY DESIGN
- 8. CASE tools Computer-Aided Software Engineering Supports specific analysis and design tasks Integrated environment that supports the entire systems development process PRELIMINARY DESIGN
- 9. PRELIMINARY DESIGN Presentation All alternatives Selected plan Prototype of the system Obtain authorization to proceed
- 10. Parts of detail design phase Output requirements Input requirements Files and databases Systems processing Systems controls and backup DETAIL DESIGN
- 11. Output requirements Medium Type of reports Contents DETAIL DESIGN
- 12. DETAIL DESIGN
- 13. Input requirements Medium Content Input forms Validation Volume DETAIL DESIGN
- 14. Files and Databases Organization Access Format of records Coordinate with database administrator regarding external databases and updating DETAIL DESIGN
- 16. DETAIL DESIGN
- 17. Systems Controls and Backup Insure that input is processed correctly Prevent fraud and tampering System journals Backup of system files DETAIL DESIGN
- 18. Report to Management Detailed design specifications report Presentation Obtain authorization to proceed DETAIL DESIGN