The spiral development model, introduced by Barry Boehm in 1986, integrates elements from the prototyping and waterfall models, focusing on project risk and stakeholder success. It is suitable for large and complex projects, facilitating early work initiation and risk evaluation, while providing a structured approach to design, development, and testing. However, the model's complexity necessitates risk assessment expertise, and it may be overly time-consuming for smaller projects.

1. By:-
Mitul K. Desai – 23

2.  This model was first described by Barry Boehm in his 1986 paper
"A Spiral Model of Software Development and Enhancement".
 Boehm describes the spiral model as a "process model generator“.
 Here choices were based on project risk.

3.  The Spiral Development ( or Lifecycle) Model is a systems
development method used in information technology.
 It combines the features of the prototyping model and the waterfall
model.
 It is favored for large, expensive, and complicated models.

4.  Consider the win conditions of all success-critical stakeholders.
 Identify and evaluate alternative approaches for satisfying the win
conditions.
 Identify and resolve risks that stem from the selected approach(es).
 Obtain approval from all success-critical stakeholders, plus
commitment to pursue the next cycle.

6.  Objectives: functionality, performance, hardware/software interface,
critical success factors, etc.
 Alternatives: build, reuse, buy, sub-contract, etc.
 Constraints: cost, schedule, interface, etc.

7.  Study alternatives relative to objectives and constraints
 Identify risks (lack of experience, new technology, tight schedules,
poor process, etc.
 Resolve risks (evaluate if money could be lost by continuing system
development

8.  Typical activities:
 Create a design
 Review design
 Develop code
 Inspect code
 Test product

9.  Typical activities:
 Develop project plan
 Develop configuration management plan
 Develop a test plan
 Develop an installation plan

10.  Estimates of the budget and schedule become more realistic as work
progresses because of the questions that have been raised
 Easier to cope with the changes inherent to software development
 Software engineers can start working on the project earlier rather
than wading through a lengthy early design process.

11.  Time spent for evaluating risks too large for small or low-risk projects.
 Time spent planning, resetting objectives, doing risk analysis and
prototyping may be excessive.
 The model is complex.
 Risk assessment expertise is required.

12.  Long-term project commitment unwise because of potential changes to
economic priorities.
 Users are unsure of their needs.
 Requirements are complex.
 New product line .
 Significant changes are expected (research and exploration).

13.  http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Spiral_model.html
 http://csse.usc.edu/csse/TECHRPTS/1988/usccse88-500/usccse88-500.pdf
 http://en.wikipedia.org/wiki/File:Spiral_model_(Boehm,_1988).svg