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Software Development Life Cycle (SDLC)

Phases in Software Development

  1. Definition and Analysis of System Requirements
    1. Clarity of the Specifications
    2. Specifications are obtained for
      1. Required processing of data
      2. Necessary functions & tasks and their expected performance
      3. Expected system behavior
      4. Design constraints
      5. Life cycle of the product
  2. Development
    1. Software design, coding and testing are the main activities in the development process.
  3. Support
    1. Software should need little support for software reengineering by changing environment

Models for process Life Cycle

  1. Linear Sequential Life cycle model
    1. Model/ Analyze
    2. Design of data structures, software architecture, Interfaces and Algorithms
    3. Testing the internal logic and external functions
  2. Rapid Development Model (RAD)
    1. Each software component of Linear Model developed by a team
    2. Stage 1 – Business modeling
    3. Stage 2 – Characteristics and attributes of sets of Data Structures and objects, data modeling, software architecture
    4. Stage 3 – Description of adding, deleting, modifying and retrieving data objects
    5. Stage 4 – Code creation
    6. Stage 5 – Testing stage
  3. Increment development model
    1. Delivering the software incrementally
    2. Stage 1 – Same as Linear Model Analyzing, designing, coding and testing
    3. Stage 2 – When 1st effort is at design, the 2nd effort starts analyzing
    4. Stage 3 – When 1st effort is at coding, the 2nd effort starts designing, the 3rd effort starts analyzing.
    5. Stage 4 - When 1st effort is at testing, the 2nd effort starts coding, the 3rd effort at designing and the 4th effort starts analyzing.
  4. Concurrent model
    1. Under development
    2. Awaiting change
    3. Under revision
    4. Done
  5. Component based model
    1. Identification of software components
    2. Selection of classes from software components library
    3. Sort available components
    4. Reengineer components and create unavailable components
    5. Construct software from the components and test them
    6. Iteratively construct till final validation
  6. Fourth Generation tool base development (4GL) model
    1. Automatic report generation for high level graphics, data base queries
    2. Automated HTML code generation when creating a website
  7. Object oriented development model
    1. Currently software development process combine object orientation and fourth generation tools

Software Analysis

  • Requirement Analysis
  • Any problem can be modeled as
    • Information domain
    • Functional domain
    • Behavioral domain
  • Prototype development and prototype specification often helps
  • Many times, it may not be possible to completely specify a problem

Software Design

  • Architectural design
  • Data design
  • Interface design
  • Component design


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