SDLC models Waterfall model Iterative model Spiral model

1. SYSTEMDEVELOPMENT LIFE CYCLE MODELS

2. OVERVIEW
 SDLC models
 Waterfall model
 Iterative model
 Spiral model

3. I. SDLCMODELS
 Is a simplified,abstracted description of a software development process
 series of steps, or phases, that provide a model for the development and
lifecycle management of an application or piece of software
 division of software development work into distinct phases or activities
with the intent of better planning and management
 subset of the systems development life cycle
Waterfall Spiral Iterative
SDLC models-

4. II.WATERFALLMODEL
 Irreversible sequential approach directing development flow downwards
(alike waterfall)
 Emphasis on planning, time schedules, target dates, budgets and
implementation of an entire system at one time

5. II.WATERFALLMODEL(CONTINUED)
Pros
Simplicity
Requirement stability
Easy structure to inexperienced staff
Effective management control (plan, staff,
track)
Pitfalls
Conventional model
Least customer participation
Debug requirement to be known at an early stage for correction- else wrong development= higher
cost of production
Rigid deliverables created at each phase
Doesn’t reflect problem solving nature of software development

6. III. SPIRALMODEL
 defined by Barry Boehm in his 1988 article A Spiral Model of Software
Development and Enhancement
 (Waterfall + Prototype) model
 adds 4th generation programming languages, rapid application
development prototyping and risk analysis to the waterfall model
 intended for large, expensive, and complicated projects

7. III. SPIRALMODEL(CONTINUED)
Identification Design Construct/Build
Evaluation and
Risk Analysis
A. Identification:
B. Design
C. Construct/Build
D. Evaluation and Risk analysis
.

8. III. SPIRALMODEL(CONTINUED)
Fig.Spiral Model

9. III. SPIRALMODEL(CONTINUED)
Pros
Avoidance of Risk is enhanced.
Strong approval and documentation
control.
Implementation has priority over
functionality.
Additional Functionality can be
added at a later date.
Pitfalls
Highly customized limiting re-usability
Applied differently for each application
Risk of not meeting budget or schedule
Possibility to end up implemented as the
Waterfall framework

10. IV. ITERATIVE MODEL
 does not attempt to start with a full specification of requirements
 development begins by specifying and implementing just part of the software, which
can be reviewed in order to identify further requirements
 more than one iteration of the software development cycle may be in progress at the
same time

11. IV. ITERATIVEMODEL
Requirements
•Gather requirements and specifications for software
Design
•New design or extension of earlier design
Implementation
and test
Review
• Software is evaluated
•Current requirements are reviewed
•Changes and additions to requirements proposed
• Software is coded, integrated and tested
Phases:

12. IV. ITERATIVEMODEL
Pros
Easy to locate flaws due to working
model of the system at a very early
stage of development
Corrective measures in a limited
budget.
Cons
Applicable only to large and bulky
software development projects
Hard to break a small software
system into further small
serviceable modules.

13. CONCLUSION
SDLC plays an important role for development of a Software product.Each SDLC phase have a separate
activities which are related to next phase.