Models and Life Cycles (Software Life Cycle Models)

17th December 2012

(docstoc, 2012)

Life cycle models describe the interrelationships between software development phases (levela, 2012).

 A software life cycle model is: "A representation of the major components of software development work and their interrelationships in a graphical framework that can be easily understood and communicated"(chambers, 2012)

The common software life cycle models are (levela, 2012):

• spiral model
• waterfall model
• throwaway prototyping model
• evolutionary prototyping model
• incremental/iterative development
• reusable software model
• automated software synthesis

1. Spiral Model -

(teced, 2012)

Is developed with the aim of reducing risks in the Software development life cycle. Spiral Model is a combination of :
  - Waterfall Model
  - Evolutionary Model
  - Incremental Model

Advantages of Spiral Model (stsc.hill, 2012)

• It provides better risk management than other models.

• Requirements are better defined.

• System is more responsive to user needs.

Disadvantages of Spiral Model (stsc.hill, 2012)

• The spiral model is more complex and harder to manage.
• This method usually increases development costs and schedule.

2. Waterfall Model (ecs.csun, 2012)

(buzzle, 2012)

 Waterfall model includes the steps: 

•  Requirements Analysis
• Software Design
• Coding
• Testing
• Maintenance

Advantages of Waterfall Model

1. Easy to understand
2. Widely used in many projects
3. Establishes milestones - when deliverables are produced and when reviews are being taken place.  

Disadvantages of Waterfall Model  

1.  Not Realistic - may not work in real world projects.
2. Does not reflect the iterative nature of projects.
3. Working software may not be available for this Model
4. Does not incorporate risk assessment

3. Evolutionary Prototyping Model (cse.unr, 2012)

(cse.unr, 2012)

 Advantages of Evolutionary Prototyping model

1. Deals constantly with changes
2. Provides quickly an initial version of the system

Disadvantages of Evolutionary Prototyping model

1. Quick Fixes may be involved
2. The system's structure can be corrupted by continuous change

 

 

Reference List

1.  Concept: Life Cycle Model [Online]. Available on : http://www.chambers.com.au/sample_p/c_pmodel.htm (Viewed on : 14th December 2012)
2. Software Life Cycle Models[Online]. Available on : http://levela.com /software_life_cycles_swdoc.htm
   (Viewed on : 14th December 2012)
3. Software Life Cycle [Online]. Available on :  http://www.stsc.hill.af.mil/resources/tech_docs/gsam4/chap2.pdf (Viewed on : 26th December 2012)
4. Software Developement life Cycle Models[Online]. Available on: www.ecs.csun.edu/~rlingard/COMP595VAV/SWLifeCycleModels.ppt (Viewed on : 26th December 2012)
5. www.cse.unr.edu/~dascalus/SE2007_04.ppt 

Images

1. http://www.docstoc.com/docs/112380032/Software-Life-Cycle-Models-%28PowerPoint%29 
2. http://teced.com/services/user-interface-design/requirements-gathering/ 
3. http://www.buzzle.com/articles/waterfall-model-diagram.html
4. http://www.wittmannclan.de/ptr/cs/slcycles.html
5. http://myrajendrak.blogspot.com/2011/03/introduction-life-cycle-models-first.html