The Systems Development Life Cycle

Agile

- small projects delivered quickly and frequently; daily collaboration with users *RAD - Rapid Application Develoment* - rapid prototyping; interactive user involvement *XP - Extreme Programming Methodology* - Tiny manageable phases; iterate with user feedback

Waterfall

- "cascades" linearly through the 7 phases

Feasibility Assessment

Economical - do benefits exceed costs? Technical - is technology available-are we up to it? Operational - can our organization operate it? Legal - does it meet all regulations and laws? Scheduling - is the *implementation* schedule practical?

Phase 4: Development

- *physical implementation* - construct *physical infrastructure* (power, AC, etc) - purchase/install hardware and software - write the programs - structure and build the database

Commercial off the shelf

- buy a ready made solution

Phase 2: Analysis

- collect/analyze data: study current system - determine business/customer requirements - write requirements definition document - sign off

Phase 6: Implementation

- complete detailed user documentation - choose the conversion method - prepare users (train on new system) - convert/start new system - get user acceptance *Users usually hate change*

Phase 5: Testing

- develop test conditions

Phase 7: Maintenance

- implement backup procedures - help users, fix problems, optimize - negotiate additional features - technical support - carefully manage change *some IS organizations spend 70% or more of their IS budget on system maintenance*

Principles of Successful Development

- keep budgets small - if it doesn't work, kill it - keep requirements to a minimum - test and deliver frequently - assign non-IT executives to software projects - ask "dumb" questions: "will customers even use this?"

Phase 1: Planning

- select the system project - assess project *feasibility* - produce project plan

Jobs involved with the SDLC

- systems analyst - systems designer/architect - systems programmer - project manager - CIO ... and many others

Reasons for Systems Development problems

- unclear or missing requirements - skipping SDLC phases - failure to manage project scope - poor project management - changing technology *This applies to all kinds of projects-not only to Information Systems*

System development methodologies

- waterfall - agile - commercial off the shelf

Phase 3: Design

Design the IT infrastructure - hardware - software Design the system components (details) - screen layouts; reports; procedures - program logic - database structure (data models/ERDs)

Implementation approach (Conversion)

Direct - switch from the old system to the one *"overnight"* Parallel - avoids some risk; *run old system until new one is working* Phased - activate new system *one module at a time* Pilot - activate and test new system *in one branch of an organization*

SDLC

Systems Development Life Cycle: 1) planning 2) analysis 3) design 4) development 5) testing 6) implementation 7) maintenance

Types of testing

Unit - does the component work as specified? Application/system - will *components work together?* Backup/recovery - will it *restart* after disaster or failure? Documentation - are *instructions accurate* and helpful? Integration - does it *work with other systems?* Regression - are other *functions* still working? User Acceptance Test (UAT) - does the system satisfy *user needs?*

Project management constraints

less time - less scope, more cost less cost - less scope, more time more scope - more time, more cost