Software Development Life Cycles

1
Software Development Life Cycles

• Linear sequential model
• classic life cycle or waterfall model
• problems
• real projects rarely follow sequential flow
• iteration hard to incorporate
• difficult for customer to give requirements
  explicitly
• working software comes late in project
• developers can be delayed by other members of
  team
• but
• provides template into which methods (techniques)
  can be placed widely used much better than ad
  hoc

2
Standard Waterfall
Requirements analysis and definition
System and software design
Implementation and unit testing
Integration and system testing
3
NCC development life cycle
Strategy
Review
Feasibility Study
Maintenance
Requirements Analysis
Implementation
Systems Analysis
Testing
Development
Specification
Design
4
Birrell and Ould b-model
Inception
development path
Definition
Design
Design
Definition
Production
Production
maintenance cycle
Inception
Acceptance
Evaluation
Operation
5
Schach waterfall model
Requirements
Verify
Specifications
Verify
Design
Verify
Implementation
Test
Integration
Test
Operations
6
Schach waterfall model, maintenance
Changed requirements
Verify
Operations
7
Londeix - V model
product qualification
product definition
system test
system architecture
subsystem specification
system integration
Subsystem integration and test
Subsystem design
software
specification code design test
8
Ould - four views model
System Design Specification
Users Views
Requirements Expression
System Specification
Module Specification
User Trial Plan
Acceptance Test Plan
Integration Test Plan
Unit Test Plan
System for Trial
Coded Units
Delivered System
Assemblages
MANAGER
USER
DESIGNER
PROGRAMMER
9
RAD Model
Team2
Team 1
10
Birrell Ould - prototyping
Inception
Use prototype
Design prototype
Definition
Investigate with user
prototyping cycle
yes
Design
no
Refine?
no
Production
Analyse Results
Acceptance