software development cycle

software development cycle

1. Software development life cycle

   • Requirements phase
     • describe the needs of the company
     • administrators, users, clients, have their wish lists
     • the analysts have asked about
       • type of data that will be processed
       • how should the data be handled
       • how to access the data
     • must have a list of functions that the system will perform:
       • emphasis on the objective of the system
       • way in which the system achieves the objectives
   • design phase
     • results of the requirements phase are translated into a design plan
     • way in which the results of the requirements phase were achieved
     • designers make dreams come true for managers and users
     • make a practical and functional design in emphasis to the requirements phase
   • Implementation phase
     • the results of the design phase are translated into the code program
     • the programmers must have an object
       • meet the requirements of the design phase
       • comply with the design drawn in the design phase
     • introduce design tools that automate the generation of code from the directive of the design phase
   • Test phase
     • are the results of the implementation phase
     • tests are run to verify that it works and meets the objectives of the requirements phase
     • The test is performed to:
       • describe the unit tests
       • describe the tests of the system to be carried out
     • Tests are performed on individual software components
     • integration process
       • gather all the software components to create a complete system
     • the test of the system is in the systematized software as a whole

2. waterfall life cycle

   • is the life cycle model
     • classic life cycle
     • sequential linear life cycle
   • is an order of steps to be completed in a linear and sequential order
   • each phase is completed and verified before the development and advance to the next phase
   • advantage
     • provides an introduction to the software life cycle models
     • It is simple and easy to use
     • each phase has a specific purpose
     • its development occurs one phase at a time
     • It is appropriate for small projects, where the requirements are well understood
   • disadvantages
     • Its use is limited due to the rigidity of the model
     • The requirements must be indicated before starting the development
     • In case the needs change or are added, you must start over
     • in case of making mistakes in the collection of design requirements a delay is created and it is possible that they will not be discovered until very late in the implementation phase
     • It is inadequate for
       • complex projects
       • object-oriented software development
       • for long-term or ongoing projects
       • for projects where the needs are unknown or are subject to change

3. life cycle model in v

   • its v-shape provides a sequential route of discrete phases
     • the phase must be completed before the development goes to the next phase
     • each phase is developed in each level, once the codification is completed, the tests are carried out
   • its development begins
     • the compilation of requirements (top left point of the v)
     • the requirements are collected and recorded as they are in the waterfall model
   • before its development goes to the next phase a test plan is created
     • focuses on verifying the functionality in the definition of requirements
     • the coding is done at the bottom of the v
     • advances on the right side of the v moving through the test plans developed during the previous phases
   • advantage
     • simple and easy
     • the objectives are defined for each phase
     • is aropiado for small projects
   • disadvantages
     • its v-form has made it unsuitable for most projects
     • it makes it difficult to add or change requirements later in the development process
     • all the development occurs in a single phase
     • If the last phase of the training, which corresponds to the first phase of development, reveals that a slight modification is necessary, the entire process should be repeated.

4. incremental life cycle

   • builds an interactive approach in the waterfall model
   • the projects divide into several smaller and more manageable interactions
   • The requirements phase, design, implementation and testing are completed for each interaction
   • its development
     • begins with the compilation of requirements and high level design
     • the requirements are divided into interactions
     • Subsequent interactions are based on the work of previous interactions
   • advantage
     • generates a functional prototype at the beginning of the development process
     • becomes more flexible when the requirements are added or changed
     • It is easier to test and debug the tests that are performed incrementally during each interaction
     • it is an effective tool to manage risk
   • disadvantages
     • the phases can not be assumed, because the compilation of requirements and the design are carried out during each interaction and not before the development begins
     • may be inappropriate for large long-term projects

5. spiral life cycle model

   • incorporate risk analysis, is divided into four phases: planning, analysis, engineering, and evaluation
   • goes through one of these phases repeatedly in a series of interferences called spirals
   • the critical requirements for the first spiral are identified
   • in the back spirals add functionality to this reference spiral
   • it is based on previous software development models. and borrows from both cascade and incremental methods
   • represented by
     • four quadrants representing the four phases of development
     • the requirements are made in the planning phase
     • the client has the opportunity to evaluate the result before the project advances
   • advantage
     • ideal for large-scale and mission-critical products
     • the client has many opportunities to evaluate the software and a lot of time to facilitate the adoption of the software
   • disadvantages
     • it may cost much more to implement than other life cycle models
     • The success of the project depends on the analysis phase since it requires very specific experience