S.D.L.C MODELS

SOFTWARE:  SET OF EXECUTABLE PROGRAMS IN A COMPUTER IS CALLED AS SOFTWARE.

S.D.L.C:- A PROCESS TO DEVELOP NEW SOFTWARE IS CALLED AS SOFTWARE DEVELOPMENT LIFE CYCLE(S.D.L.C.)   THESE S.D.L.C MODELS ARE OF TWO TYPES

• TRADITIONAL MODELS   (OLD MODELS) 

  • NEW MODELS

   

   

   

   

   

   

   

   

   

   OLD  S.D.L.C.  MODELS :

  1)WATER FALL MODEL:   The Waterfall Model was first Process Model to be introduced. It is also referred to as a linear-sequential life cycle model.  It is very simple to understand and use.  In a waterfall model, each phase must be completed fully before the next phase can begin.   At the end of each phase, a review takes place to determine if the project is on the right path and whether or not to continue or discard the project. In waterfall model phases do not overlap         

  

  Advantages of waterfall model:
  
• Simple and easy to understand and use.
• Easy to manage due to the rigidity of the model – each phase has specific deliverable s and a review process.
• Phases are processed and completed one at a time.
• Works well for smaller projects where requirements are very well understood.

        Disadvantages of waterfall model:

• Once an application is in the testing stage, it is very difficult to go back and change something that was not well-thought out in the concept stage.
• No working software is produced until late during the life cycle.
• High amounts of risk and uncertainty.
• Not a good model for complex and object-oriented projects.
• Poor model for long and ongoing projects.
• Not suitable for the projects where requirements are at a moderate to high risk of changing
  
  
  
  
  When to use the waterfall model:
  
  
• Product definition is stable.
• Technology is understood.
• Requirements are very well known, clear and fixed.
• There are no ambiguous requirements
• Ample resources with required expertise are available freely
• The project is short

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  2).prototype model:               IF CUSTOMER REQUIREMENTS  ARE NOT CLEAR,CORRESPONDING BUSINESS ANALYST CAN GIVE DEMO ON MODEL SOFTWARE SCREENS TO GET CLARITY FROM CUSTOMERS ON SOFTWARE .

  Prototyping approach, also known as evolutionary approach, came to picture because of failures that occurred in the final version of the software application developed using the waterfall approach. The failure generally occurs because of the changes in the requirement of the proposed system or because of the gap in understanding the customer requirement by the development team. A gap in the first version of the developed application, inevitably leads to the need for redoing the application. To overcome these limitations, the concept of prototyping was introduced.

   

  

  prototype model

   

   

   

   

   

   

   

   

   

   

   

   

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MANUAL TESTING

Manual Testing:

 This type includes the testing of the Software manually i.e. without using any automated tool or any script. In this type the tester takes over the role of an end user and test the Software to identify any UN-expected behavior or bug. There are different stages for manual testing like unit testing, Integration testing, System testing and User Acceptance testing.

https://www.youtube.com/watch?v=xCwkjZcEK6w

PRECISION TESTING FOR QUALITY SOFTWARE

what is Software Testing? 

• It is the process in which Defects are detected,isolated and subject for Rectification,finally ensuring that application or software is Error free,Defect free.

•  It is the process used to assess the quality of computer Software.

• •  I.E.E.E definition states "Testing is the process of exercising or evaluating a system or system components by manual or Automated means to verify that it satisfies specified requirements "
  
  
    There are two types of Testing
  •  1. Manual Testing
  •  2.Automated Testing