MODULE 2 : SOFTWARE PROCESS

The waterfall model is a sequential design process, often used in software development processes, in which progress is seen as flowing steadily downwards (like a waterfall) through the phases of Conception, Initiation, Analysis, Design, Construction, Testing, Production/Implementation and Maintenance, manufacturing and construction industries: highly structured physical environments in which after-the-fact changes are prohibitively costly, if not impossible. Since no formal software development methodologies existed at the time, this hardware-oriented model was simply adapted for software development.

The first known presentation describing use of similar phases in software engineering was held by Herbert D. Benington at Symposium on advanced programming methods for digital computers on 29 June 1956. This presentation was about the development of software for SAGE. In 1983 the paper was republished with a foreword by Benington pointing out that the process was not in fact performed in strict top-down, but depended on a prototype.

Post by: Nur Liyana

Spiral Model Advantages

• Repeated or continuous development helps in risk management. The developers or programmers describe the characteristics with high priority first and then develop a prototype based on these. This prototype is tested and desired changes are made in the new system. This continual and steady approach minimizes the risks or failure associated with the change in the system.
• Adaptability in the design of spiral model in software engineering accommodates any number of changes, that may happen, during any phase of the project.
• Since the prototype building is done in small fragments or bits, cost estimation becomes easy and the customer can gain control on administration of the new system.
• As the model continues towards final phase, the customer's expertise on new system grows, enabling smooth development of the product meeting client's needs.

Spiral Model Disadvantages

The following can be summarized as the disadvantages of the spiral model.

• Spiral models work best for large projects only, where the costs involved are much higher and system pre requisites involves higher level of complexity.
• Spiral model needs extensive skill in evaluating uncertainties or risks associated with the project and their abatement.
• Spiral models work on a protocol, which needs to be followed strictly for its smooth operation. Sometimes it becomes difficult to follow this protocol.
• Evaluating the risks involved in the project can shoot up the cost and it may be higher than the cost for building the system.
• There is a requirement for further explanation of the steps involved in the project such as breakthrough, blueprint, checkpoints and standard procedure.

Post by : Rosfazila