SDLC Lecture Notes PDF

System Development Life Cycle (SDLC)  CSC317: Lecture 5  Igbekele Emmanuel O. Ph.D The System Development Life Cycle What is an information system (IS)? Hardware, Hardware,software, software,data, data, System—Set...

System Development Life Cycle (SDLC)  CSC317: Lecture 5  Igbekele Emmanuel O. Ph.D The System Development Life Cycle What is an information system (IS)? Hardware, Hardware,software, software,data, data, System—Set System—Setof ofcomponents components people, people,and andprocedures proceduresthat that that thatinteract interactto toachieve achieve work worktogether togethertotoproduce produce common commongoalgoal quality qualityinformation information Businesses Businessesuse usemany manytypes typesofof systems systems System Development Life Cycle (SDLC) System Development Life Cycle (SDLC) The System Development Life Cycle What are the phases of the system development cycle? Phase 2. Analysis  Conduct preliminary investigation Phase 1.  Perform detailed analysis activities:  Planning Review project requests Phase 3. Study current system Acquire hardware  Design  Prioritize project Determine user requirements and software, if requests necessary Recommend solution  Allocate resources  Develop details of  Identify project system development team Phase 5. Support Phase 4.  Implementation Develop programs, if necessary  Conduct post-implementation system review  Install and test new system  Identify errors and enhancements  Train users  Monitor system performance  Convert to new system The System Development Life Cycle What are guidelines for system development? Arrange tasks into phases (groups of activities) Involve users (anyone for whom system is being built) Develop clearly defined standards (procedures company expects employees to follow) The System Development Life Cycle Who participates in the system development life cycle? The System Development Life Cycle What is a systems analyst? Responsible for designing and developing information system Liaison between users and IT professionals The System Development Life Cycle What is the project team? Formed to work on project from beginning to end Consists of users, systems analyst, and other IT professionals Project leader—one member of the team who manages and controls project budget and schedule The System Development Life Cycle What is feasibility? Operational feasibility Measure of how suitable system Four feasibility development tests: will be to the Schedule company feasibility Economic feasibility (also called Technical cost/benefit feasibility feasibility) The System Development Life Cycle What is documentation? Collection and summarization of data and information Includes reports, diagrams, programs, and other deliverables The System Development Life Cycle What are six data and information gathering techniques?  Review documentation  Observe  Questionnaire  Interview  Joint-application design (JAD) session  Research The System Development Life Cycle What are some reasons to create or modify an information system? To correct problem To improve in existing system existing system Outside group may Competition can mandate change lead to change The System Development Life Cycle What is a request for system services?  Formal request for new or modified information system  Also called project request The System Development Life Cycle What is the planning phase? Begins when steering committee receives project request Steering committee— decision-making body for the company Function of committee: Form project Review and development Prioritize Allocate approve project team for each project requests resources requests approved project The System Development Life Cycle What is the analysis phase? Conduct preliminary Perform detailed investigation, also analysis called feasibility study The System Development Life Cycle What is the preliminary investigation?  Determine exact nature of problem or improvement and whether it is worth pursuing  Findings are presented in feasibility report, also known as a feasibility study The System Development Life Cycle What is detailed analysis? 1. Study how current system works 2. Determine user’s wants, needs, and requirements 3. Recommend solution Sometimes called logical design The System Development Life Cycle What is the system proposal? Assesses feasibility of each alternative solution Presented to Recommends steering the most committee, feasible which decides solution for how system will the project be developed The System Development Life Cycle What are possible solutions? Horizontal Horizontalmarket market software—meets software—meets needs needsofofmany many companies Buy Buypackaged packagedsoftware—prewritten software—prewritten companies software softwareavailable availablefor forpurchase purchase Vertical Verticalmarket market software—designed software—designed for forparticular particularindustry industry Write Writeown owncustom customsoftware—software software—software developed developedat atuser’s user’srequest request Outsource—have Outsource—haveoutside outsidesource source develop developsoftware software The System Development Life Cycle What is the design phase? Acquire Acquirehardware hardwareand andsoftware software Develop Developall alldetails detailsof ofnew newor or modified modifiedinformation informationsystem system The System Development Life Cycle What is needed to acquire new hardware and software?  Identify all hardware and software requirements of new or modified system Talk with other Surf Web systems analysts Read print and Visit vendors’ stores online trade journals, newspapers, and magazines The System Development Life Cycle What are three basic documents used to summarize technical specifications? Vendor quotes Identifies Request for quotation (RFQ) price(s) for product(s) listed you want product(s) Vendor selects Request for proposal (RFP) product(s) that meet(s) your requirements and Less formal method then quotes price(s) that uses standard form to request information about Request for information (RFI) product or service The System Development Life Cycle How do systems analysts test software products?  References from vendor  Talk to current users of product  Product demonstrations  Trial version of software  Benchmark test measures performance The System Development Life Cycle What is a detailed design? Detailed design specifications for components in proposed solution Includes several activities Database Database Input Inputand and Program Program design design output outputdesign design design design The System Development Life Cycle What is a mockup?  Sample of input or output that contains actual data The System Development Life Cycle What is a prototype? Working model of proposed system Beginning a prototype too early may lead to problems The System Development Life Cycle What is computer-aided software engineering (CASE)?  Software tools designed to support activities of system development cycle The System Development Life Cycle What is the implementation phase?  Purpose is to construct, or build, new or modified system and then deliver it to users Convert to new system Train users Install and test new system Develop programs The System Development Life Cycle What are the three types of tests performed by system developers? Unit Test Systems test Verifies each Verifies all programs individual program in application work works by itself together Integration Test Verifies application works with other applications The System Development Life Cycle What is training?  Showing users exactly how they will use new hardware and software in system The System Development Life Cycle What is the support phase?  Provides ongoing assistance after system is implemented Conduct post-implementation system review—meeting to find out if information system is performing according to expectations Identify errors Identify enhancements Monitor system performance