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 1^st effort is at design, the 2^nd effort starts analyzing
      
   4. Stage 3 – When 1^st effort is at coding, the 2^nd effort starts designing, the 3^rd effort starts analyzing.
      
   5. Stage 4 - When 1^st effort is at testing, the 2^nd effort starts coding, the 3^rd effort at designing and the 4^th 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