Software process model-Final

‘Software Process Models’:

‘Software Process Models’ B y Aisha C ME Software systems ID No 2010H112002U BITS Pilani Duba i

Slide 2:

Topics covered What is Software Model Types of Model Advantage Conclusion

Slide 3:

What is Software model 1. A Software process model is an abstract representation of a process. It presents a description of a process from some particular perspective. 2. A software model is an abstract representation of architecture, design or definition of the software process

Slide 4:

Type of Models There are 3 types of models Water fall model – This takes the fundamental process activities of specification, development ,validation and evolution Evolutionary Development- Specification,Devlopment and validation are interleaved Component based software engineering- The system is assembled from existing components. These 3 Generic process models are widely used in current software engineering practice. These models are not mutually exclusive and are often used together especially for large systems development.

Slide 5:

Water Fall Model Water fall model Derived from general system engineering processes by Royce in 1970 This model is cascade from one phase to another this model is called the Waterfall model or the Software life cycle. Requirements definition Implementation & Unit testing System & software design Integration & System testing Operation & Maintenance

Slide 6:

Waterfall Model Water fall Model Problems Inflexible partitioning of the project in to distinct stages makes it difficult to respond to changing customer requirements This models is appropriate when the requirements are well understood and changes will be fairly limited during the design process. Few business systems have stable requirements. The Waterfall model is mostly used for large systems engineering projects where a system is developed at several sites. Advantage of Waterfall Model The documentation is produced at each phases and that fits with other process Models Draw back of Waterfall Model Difficulty of accommodating change after the process is underway. One phase has To be complete before moving on to the next phase.

Slide 7:

Evolutionary Development Model It is based on the idea of developing an initial implementation, exposing this to user comment & refining it through many versions until an adequate systems has been Developed. Outline Description Specification Development Validation Initial Version Intermediate Version Final Version

Slide 8:

Evolutionary devlopment Model 2 Fundamental type of Evolutionary development Exploratory Development Objective is to work with customers & to evolve a final system from an initial outline Specification. Should start with well- understood requirements and add new features as proposed by the customer Throw-away Prototyping Objective is to understand the system requirements. Should start with poorly understood requirements to clarify what really is needed.

Slide 9:

Evolutionary Development Model Problems Lack of Process visibility Systems are often poorly structured. Special skills may be required Applicability For Small or medium size interactive systems For parts of large systems (example User Interface)

Slide 10:

Components based Software Engineering Based on systematic re use where systems are integrated from existing components of COTS (Commercial- Off-The-Shelf) systems Requirements Specification Component Analysis System design with reuse Requirement modification Development and Integration System Validation Advantages Reduces amount of software to be developed and so reduces costs and risks. It leads to faster delivery of software to the customer

Slide 11:

1.Software process models are abstract representation of these processes. 2.General activities are specification, design and implementation, validation and evolution 3.Generic process models describe the organization of software processes. Examples include the waterfall model, evolutionary development and component-based software engineering. 4.The most appropriate software process model depends on the organization developing the software, the type of software being developed and the capabilities of staff. There is no ‘’ideal model and it makes little sense to try to fit all development into a single approach. CONCLUSION

Slide 12:

THANK YOU FOR YOUR ATTENTION ANY ? REFERENCES www.com.lancs.ac.uk