CS405 Systems Development Life Cycle 1

Traditional Project Phases Wild Enthusiasm Growing Concern Mounting Terror Resigned Fatalism Persecution of the Innocent Promotion of the Uninvolved 2

SDLC Phases SDLC phases Project Initiation Requirements definition Detail design Construction Integration testing Implementation “Methodology” A formal statement of the purpose, products and tasks for each phase Many software development companies have either created or adopted a methodology to ensure process consistency and system quality 3

SDLC Phases Project initiation (5% of total effort) Why » Determine overall desirability » Allow project to be prioritized vis-à-vis other projects What » Project Initiation Report outlining Value of the project Proposed technologies Projected cost of the project Expected timeline » accurate +/- 100% How » Interviews with the business » Technology evaluation 4

SDLC Phases Requirements Definition (15% of total effort) Why » Create a “contract” for what is to be developed What » System Functional Requirements A business flow showing how the users will interact with the system in performing various supported business functions All input/output displays/reports should be defined precisely in terms of the data content at the data field level (see Data Dictionary) and the desired functionality. Exact screen/report layout is not important A Data Dictionary defining each data field to be used on displays and reports Detailed project plan for next phase; high-level project plan for remaining phases Revised project cost and timeline Should identify potential risk factors; e.g. new technology, multi-national project organization, etc. Accurate to +/- 50% 5

SDLC Phases How » User interviews » Technology evaluation » Walkthroughs of the proposed system “Playscripts” » Management review and approval to procede to the next phase 6

SDLC Phases Detail design (20% of total effort) Why » Finalize the design of the entire system for sponsor approval and actual development » Create a basis for vendor bidding and selection What » Final in/output displays/reports » Detail description of inputs/outputs to/from other systems » Final logical database design » High-level software specifications » Revised project cost/timeline accurate to +/- 10% 7

SDLC Phases How » Detail display/report design » Detail interface design » Detail logical database design » High-level software design » Validation sessions with sponsors » Project planning and cost estimates Remainder of the project phases should be planned in detail 8

SDLC Phases Construction and Unit Testing (20% of total effort) Why » Develop a working system » Demonstrate that individual components perform as specified. » Prepare for integration testing and implementation What » A working database » Working software » Unit test results » Integration test plan » Implementation plan How » Detail logic design » Coding » Unit testing 9

SDLC Phases Integration Testing (30% of total effort) Why » Ensure that all elements of the systems interact correctly under all circumstances » Ensure that the system will give acceptable performance under the volume of processing expected What » A fully tested system » Completed system documentation » Authorization to proceed to implementation 10

SDLC Phases How (a “black art”) » String testing » Scenario testing “day-in-the-life” testing playscripts » Parallel testing Run an actual day and compare to what the old system produced Very time consuming/expensive » Implementation testing Test conversion programs, history loading programs, etc. » Performance testing 11

SDLC Phases Implementation (10% of total effort) Why » Implement a working system What » “live” application How » Hardware installation » Software installation/roll out » User training » Data conversion » Cut over » Post-implementation support (“hypercare”) 12