Winston. W. Royce in 1970 first coined the term The Water Fall Model in an article for a sequential design process. The task execution of the model is comprised of six different stages one after the other. It works on a mechanism that if one stage is not completely finished the next stage doesn’t starts. In the first stage no matter you are designing for a large or small model you must have an idea about what finish product you want you have to mould your design structure in this stage.
In second stage the whole functionality of the software design is decided. In Third stage work starts and all important stages like coding, algorithm, designing, database management and every other aspect is dealt with. In fourth stage the testing and correction process starts. Integration and handover to client takes place in next phase the sixth stages involves reviewing and debugging and helping the client with the software management.
The biggest disadvantage of the software is that we cannot undo the written stuff. If the client is not clear in his mind about what exactly he wants from the stage one it becomes extremely difficult to make alteration in the implementation phase. To prevent such issues we freeze the hardware and software but with advancement and updated technology that cannot be easily done. Since all stages are inter linked so a single small change carries a big problem for the next executable stage. Going back and forth is a very highly costly process. The water fall software is based on linear model which is not best suited for long term use. It is a very highly risky and uncertain model because if you find problems at the very end you are at the losing end. It doesn’t fulfill the requirements of long term and ongoing projects.