Waterfall approach

 The software process model is still the object of research, but now there are many different general models or paradigms of software development, including:

Waterfall approach

Contains a series of process activities as described above and presented in a separate process, such as requirements specification, software design implementation, testing and so on. After each step is defined, it is signed off and development continues in the next step. 

Waterfall

This model has been obtained from other engineering processes. This model offers a more realistic way of making software.



The steps that are important in this model are

• Determination and analysis of specifications
  

Services, constraints and objectives resulted from consultation with system users. Then they are created in a form that is understandable to both the user and the development staff.

• System and software design
  

The system design process divides the requirements into software or hardware systems. This process produces a whole system architecture. Software design includes producing software system functions in a form that may be transformed into one or more executable programs.

• Implementation and unit testing
  

During this stage the software design is recognized as a complete program or program unit. Unit tests include testing that each unit conforms to specifications.

• System integration and testing
  

Program units are integrated and tested into a complete system to ensure that the software requirements are met. After testing, the system is delivered to the customer

• Operation and maintenance
  

Normally, this is the longest phase. The system is installed and used.

Maintenance includes correcting errors that were not found in the previous step. Improved system unit implementation and improved system services as new needs were found.


In practice, each step often overlaps and informs one another. The software process is not linear and simple but contains an iterative sequence of development activities. During the last step, the software has been used. Errors and omissions in determining the need for original software can be overcome.



Unfortunately, the iteration-heavy model makes it difficult for management to go over all plans and reports. Therefore, after a little iteration, usually the part that has been developed will be stopped and continued with the next development step. Problems during subsequent resolutions, are ignored or programmed. Premature termination of the requirement will mean that the system will not conform to the user's wishes. It is also possible that a poorly structured system which is actually a design problem will be left to overpower the implementation tricks.



The problem with the waterfall approach is the irregularity of dividing the project into clear steps. Sometimes the system that is delivered cannot be used according to the wishes of the customer. However, the waterfall model reflects engineering practicality. Consequently, a software process model based on this approach is used in the development of a wide range of software and hardware systems.