summary for midterm

3. the scope of S/W engineering the software process UNIFIED PROCESS -software development is process. -most software developers follow phases of lifecycle. -organizations phases differently such as requirements and specification phase = analysis phase -in 1999, published complete OO analysis and design methodology – unified 3 separate approaches. THE REQUIREMENTS PHASE -aim: explore and determine -what the client needs, not they want. 1. gain understanding of application domain (learn about specific environment) 2. build a functional/operational model for S/W -check what is the limit by clients: deadline, parallel running, portability, reliability, rapid response time, cost. -final product is not what client wants because : miscommunication, it is not what they need, misunderstanding requirements, missed deadlines, moving target ANALYSIS PHASE (SPECIFICATION) -aim: analyze and refine requirements – formal contract -requirements artifacts in simple human language for client, and analysis artifacts must be precise and complete for designers. -specification documentation is important to be corrected and completed because of testing and maintenance. -specification document must not have: contradictions, omissions, vague statements, and incompleteness. Software PROJECT MANAGEMENT PLAN (SPMP) -it is including budget and time estimating, deliverables, and milestones DESIGN PHASE -aim: to refine analysis phase until material is in a form that can be coded/implemented by programmers. To show “how” the software will do. -many non-functional requirements must be finalized CLASSICAL (STRUCTURED) VS. OBJECT ORIENTED -objects introduced in analysis workflow -interaction among objects are determined OO analysis workflow -objects are designed in OO design workflow and coded during OO implementation workflow -OO workflows are very smooth because of the interaction between the phases. *structured paradigm -analysis: determine what the product is supposed to do -architectural design: determine and extract software modules -detailed design: design modules -implementation: code the modules in an appropriate programming language *OO paradigm -analysis: determine what the product is supposed to do and extract the classes -design: design the objects and interaction among them -implementation: code the modules in an appropriate programming language THE IMPLEMENTATION PHASE -use selected implementation language -large software: development (coding) first and then implementation later -when modules are integrated, new problems may show up. TEST PHASE -test is responsibility of every developer, maintainer and SQA group. -traceability of artifacts (specification doc. -> requirements doc.) POST-DELIVERY MAINTENANCE -essential component of software development (the most expensive phase) -open-ended design -> flexible product -> easier to maintain -lack of documentation -design must include future maintenance 1. unit testing: test the new module with new data 2. integration testing: run modified software with new test 3. regression testing: run modified software with old test data and compare results with pre-change test results RETIREMENT -software can be un-maintainable because: 1) hardware and OS keep changing (should be implemented in it) 2) documents missing or inaccurate 3) a huge change in design has occurred DESIGN ARTIFACTS -bridge between analysis and implementation -design doc. -> specification doc. -client representative usually not present IMPLEMENTATION ARTIFACTS -each component is tested during implementation – unit testing -completed components are added incrementally and one at a time -integration testing is done to make sure the combined components work together: top down-nothing to show the client until all is done, bottom up-always have something to show client. -when product appears to be complete, it is tested as a whole – product testing -after completed product is installed on client’s computer, they test it – acceptance testing -implementation doc -> design doc. -COTS (commercial off-the shelf) software is released for testing by prospective clients -alpha: employees of vendor company use product for free -beta release: corrected alpha version is used in beta testing. Closer to the final. Advantage of alpha or beta release -get a head start, using new product -learn it before competitors Disadvantage of alpha or beta release -errors can slow down daily activity, damage company dBase, and cause frustration. 4. TEAM ORGANIZATION TEAM ORGANIZATION -specification and design may be done individually, but software development and implementation always done by different teams. -incorrect order of arguments, number of arguments and type of arguments can go wrong. *Brooks law: adding additional programmers to a team when product is late, can make product even later DEMOCRATIC TEAM APPROACH (Weinberg, 1970s) -team members “review” each other’s code and looking for faults -start through team until the end -team members don’t “evaluate” other members’ “performance” *advantage 1. positive att