Models of Software Development Life Cycle (SDLC)

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Models of Software Development Life Cycle (SDLC)

• The objective of this section is to introduce you
  the idea of software process a coherent set of
  activities for software production. When you have
  read this section you will
• understand the concept of a software process and
  a software process model
• understand a number of different software process
  models such as waterfall, spiral and iterative
  models.

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What is a SDLC Model?

• An SDLC model breaks down the development process
  into a sequence of phases or stages.
• The end of a phase is called a milestone of the
  project. The outcome of the phase is delivered to
  the customer as a milestone of the project.
• Breaking down the development process makes it
  easier to manage.
• Each phase can be performed in various ways.

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Why use SDLC Model?

• In the earlier days, projects were developed
  without proper specification or any attempt in
  design and were just built, and reworked as many
  times needed to satisfy the customer.
• This is not possible for complex projects since
• There is no control on quality assurance.
• There is no risk analysis.
• There is no estimation of time and cost of the
  project.
• There is no proper plan.
• Hence,
• The project may lead to a huge financial loss for
  both the customer as well as the developer.
• The project may fail.
• The project may not be delivered in time with the
  satisfaction of the customer.

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1. Waterfall Model

• In the waterfall model, software activities
  proceed logically through a sequence of steps.
  Each step bases its work on the activities of the
  previous step. The design phase logically follows
  the requirements phase, the implementation phase
  follows the design phase, and so on.
• Waterfall model is document driven. In principle,
  the result of each phase is one or more documents
  which are approved (sign-off). The next phase
  should not start until the current phase is
  completed.

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Workflow of Waterfall Model
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Quiz

• The planning of the project is done by
• The programmer
• The system analyst
• The system study team
• The project manager
• During the Specification mode, the requirements
  are properly documented and the document is
  called _________.
• The waterfall model is
• Document-driven.
• Risk-driven
• Prototype-driven