Software Development Life Cycle

Nota:

• The Incremental life cycle model builds an iterative approach into the Waterfall model. Development projects are divided into several smaller, more manageable iterations. Each iteration passes through a mini-Waterfall process. Requirement, design, implementation and testing phases are completed for each iteration.

1. REQUIREMENTS

   Nota:

   • During the requirements-gathering phase, the needs of the company are outlined. Following the requirements phase, the software development team should have a detailed list of functions that the system will perform. Emphasis is on the system's goals, rather than the way in which the system will achieve those goals.
   1. DESIGN

      Nota:

      • In the design phase, the results of the requirements-gathering phase are translated into a software design plan. Focus shifts from the system's results to the way in which those results will be achieved and how the ideas of the requirements-gathering phase are accomplished. In essence, during the design phase, the designers attempt to turn the dreams of the managers and users into reality.
      1. IMPLEMETATION AND UNIT TESTING

         Nota:

         • All the units developed in the implementation phase are integrated into a system after testing of each unit. The software designed, needs to go through constant software testing to find out if there are any flaw or errors. Testing is done so that the client does not face any problem during the installation of the software.
         1. INTEGRATION AND SYSTEM TESTING

            Nota:

            • The modules that are divided into units are integrated into a complete system and tested for proper coordination among modules and system behaves as per the specifications. Once the testing is completed, the software product is delivered to the customer.
            1. OPERATION

               Nota:

               • It is a never ending phase. Once the system is running in production environment, problems come up. The issues that are related to the system are solved only after deployment of the system. The problems arise from time to time and need to be solved; hence this phase is referred as maintenance

Nota:

• The Spiral model is represented by a spiral passing through four quadrants, whichrepresent the four phases of development. Requirements gathering is performed in theplanning phase. During the risk analysis phase, a formal process is undertaken to identify

1. PLANNING
   1. RISK ANALYSIS
      1. ENGINEERING
         1. EVALUATION
            1. CUSTOME EVALUATION
               1. PROJECT COST
         2. CODING
            1. TESTING
      2. RISK ANALYSIS
         1. PROTOTYPING
   2. REQUIREMENTS GATHERING

      Nota:

      • During the requirements-gathering phase, the needs of the company are outlined. Following the requirements phase, the software development team should have a detailed list of functions that the system will perform. Emphasis is on the system's goals, rather than the way in which the system will achieve those goals.

Nota:

• Like the Waterfall model, the V-Shaped life cycle model provides a sequential path of discrete phases that must each be completed before development proceeds to the next phase. The phase test plans are developed during each level of development, and once coding is completed, the tests are conducted.

1. REQUIREMENTS

   Nota:

   • During the requirements-gathering phase, the needs of the company are outlined. Following the requirements phase, the software development team should have a detailed list of functions that the system will perform. Emphasis is on the system's goals, rather than the way in which the system will achieve those goals.
   1. HIGH LEVEL DESIGN

      Nota:

      • Systems design is the phase where system engineers analyze and understand the business of the proposed system by studying the user requirements document. They figure out possibilities and techniques by which the user requirements can be implemented. If any of the requirements are not feasible, the user is informed of the issue. A resolution is found and the user requirement document is edited accordingly.
      1. LOW LEVEL DESING

         Nota:

         • in this phase some details that are missing in the high level design are corrected or added.
         1. IMPLEMETATION

            Nota:

            • Phase is, again, where all coding takes place. Once coding is complete, the path of execution continues up the right side of the V where the test plans developed earlier are now put to use.
            1. UNIT TESTING
               1. INTEGRATION TESTING
                  1. SYSTEM TESTING
                     1. SYSTEM TEST PLANNING
                  2. INTEGARTION TEST PLANNING
               2. UNIT TEST PLANNING

Nota:

• The term software development life cycle model is a way of describing the planning, designing, coding, and testing of a software system, as well as the method in which these steps are implemented.

1. REQUIREMENTS-GATHERING

   Nota:

   • During the requirements-gathering phase, the needs of the company are outlined. Following the requirements phase, the software development team should have a detailed list of functions that the system will perform. Emphasis is on the system's goals, rather than the way in which the system will achieve those goals.
2. DESIGN

   Nota:

   • In the design phase, the results of the requirements-gathering phase are translated into a software design plan. Focus shifts from the system's results to the way in which those results will be achieved and how the ideas of the requirements-gathering phase are accomplished. In essence, during the design phase, the designers attempt to turn the dreams of the managers and users into reality.
3. IMPLEMENTATION

   Nota:

   • During this phase the programmers should make it their central goal to fulfill the requirements of the company and to meet the design outlined in the design phase. The classes and class interactions developed in the design phase are very explicit.
4. TESTING

   Nota:

   • In the testing phase, the results of the implementation phase are run through a series of tests to verify that it functions and that it meets goals of the requirements phase.

Nota:

• The Waterfall life cycle model, also known as the classic or linear-sequential life cycle model, is one of the simplest to understand and use. The Waterfall model is characterized by a series of steps that must be completed in a linear, sequential order. Each phase is completed and verified before development progresses to the next phase. "This model can be easy to implement and manage because each phase has a specific purpose, and development occurs in only one phase at a time. The Waterfall model is appropriate for small development projects in which the requirements are well understood." "If requirements change or are added, the project must start over from the beginning. No working software is developed until very late in the process, and this delay creates a great deal of uncertainty and risk. If errors are made in requirements-gathering or design, they may not be discovered until very late in the implementation or testing phases. Due to these issues, the Waterfall model is inappropriate for complex projects. It should not be used for developing object-oriented software, for long-term or ongoing projects, or for projects in which requirements are unknown or subject to change."

1. REQUIREMENTS

   Nota:

   • During the requirements-gathering phase, the needs of the company are outlined. Following the requirements phase, the software development team should have a detailed list of functions that the system will perform. Emphasis is on the system's goals, rather than the way in which the system will achieve those goals.
   1. DESIGN

      Nota:

      • In the design phase, the results of the requirements-gathering phase are translated into a software design plan. Focus shifts from the system's results to the way in which those results will be achieved and how the ideas of the requirements-gathering phase are accomplished. In essence, during the design phase, the designers attempt to turn the dreams of the managers and users into reality.
      1. IMPLEMETATION AND UNIT TESTING
         1. INTEGRATION AND SYSTEM TESTING

            Nota:

            • The modules that are divided into units are integrated into a complete system and tested for proper coordination among modules and system behaves as per the specifications. Once the testing is completed, the software product is delivered to the customer.
            1. OPERATION

               Nota:

               • It is a never ending phase. Once the system is running in production environment, problems come up. The issues that are related to the system are solved only after deployment of the system. The problems arise from time to time and need to be solved; hence this phase is referred as maintenance