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28/10/10 - Rival Schools on SD

posted Oct 27, 2010, 2:31 PM by Unknown user   [ updated Nov 9, 2010, 2:57 AM ]

Waterfall (most in common with SDLC)

  • Concrete beginning and end
  • Sequential
Rationale: Detailed planning at beginning will save time, money and effort later on. A rigid timeline will ensure that the project is completed on schedule.

Most suitable scenario: The presence of a due date


Spiral
  • Develop successive working versions that learn from discoveries and mistakes of earlier versions
Successive - one after another (replaced)
Working - has to function
Versions - prototypes, iterations, builds, milestones
  • Increases progressively in scope, budget

Agile
  • Accelerated delivery to respond to user feedback
  • Prefers response/adaption over a rigid structure
  • Values close collaboration with final users of system all the way through development
Rationale: Allows for backtracking and provides client with opportunity for feedback

Problems that may arise: User feedback presents itself as competing or a waste of time, pestering of client
 

Describe the Waterfall, Spiral and Agile methodologies.

The Waterfall method has a concrete beginning and end, and is sequential. Detailing planning at beginning will save time, more $ and effort later on. A rigid timeline will ensure that the project is completed on schedule.
 
The Spiral method develops successive working versions that learn from discoveries and earlier mistakes of earlier versions. It eventually increases in scope and budget.
 
The Agile method is the accelerated delivery of versions to allow for response to user feedback. It prefers response/adaptation over a rigid structure. It values close collaboration with final users of the system all the way through development.

Explain the key benefits and disadvantages associated with each one, making sure to show how each benefit and disadvantage is caused directly by the specific principles of each methodology.

Waterfall
 
Advantages: Detailed planning at beginning will save time, money and effort later on. A rigid timeline will ensure that the project is completed on schedule.
 
Disadvantages: Not flexible
 
 
Spiral
 
Advantages: Working versions continually developed for showcase
 
Disadvantages: $ may be spent on insignificant versions/improvements
 
 
Agile
 
Advantages: Accelerated delivery, close collaboration with final users of system all the way through development
 
Disadvantages: Makes clients grumpy
 
 
Research the following scenarios and then select a methodology that you think suits the development of the relevant system. With close reference to the unique characteristics of each situation, justify your choice.
 
Google implements its Google Instant search system.

Agile

The aim of the Google Instant search system to ensure the search time of the user is reduced. Until users actually trial the systems, the effectiveness of the developed system cannot be gauged. Whilst in development, any user feedback can be collected and implemented faster and with less cost, given its close collaboration with users.  
 
Apple releases the iPhone 4.

Waterfall

The iPhone 4, one of the major products of Apple, would require a fairly rigid timeline to ensure that a due date is met for release. Given that iPhone 4 is very much a piece of hardware, once it is delivered to clients - there would be no chance to fix problems or respond to user feedback,
 
Microsoft publishes Windows 7.
 
Spiral
 
The development of successive working versions allows the flexibility to add additional features, whilst keeping to a timeline. The ability to constantly re-design programs is important given the inter-reliance of features in an operating system.

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