Jan Lokpal Bill Essay on Various Advantages and Disadvantages of It

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CS51 SOFTWARE ENGINEERING UNIT I SOFTWARE PRODUCT AND PROCESS Software engineering paradigm: • The framework activities will always be applied on every project ... BUT the tasks (and degree of rigor) for each activity will vary based on: – the type of project – characteristics of the project – common sense judgment; concurrence of the project team The software process: • A structured set of activities required to develop a software system – Specification; – Design; – Validation; – Evolution. • A software process model is an abstract representation of a process. It presents a description of a process from some particular perspective. Waterfall model/Linear Sequential Model/classic life cycle :

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Systems Engineering – Software as part of larger system, determine requirements for all system elements, allocate requirements to software. Software Requirements Analysis – Develop understanding of problem domain, user needs, function, performance, interfaces, ... – Software Design – Multi-step process to determine architecture, interfaces, data structures, functional detail. Produces (high-level) form that can be checked for quality, conformance before coding. Coding – Produce machine readable and executable form, match HW, OS and design needs. Testing

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Confirm that components, subsystems and complete products meet requirements, specifications and quality, find and fix defects. • Maintenance – Incrementally, evolve software to fix defects, add features, adapt to new condition. Often 80% of effort spent here! Waterfall model phases: • Requirements analysis and definition • System and software design • Implementation and unit testing • Integration and system testing • Operation and maintenance • The main drawback of the waterfall model is the difficulty of accommodating change after the process is underway. One phase has to be complete before moving onto the next phase. • Each phase terminates only when the documents are complete and approved by the SQA group. • Maintenance begins when the client reports an error after having accepted the product. It could also begin due to a change in requirements after the client has accepted the product Waterfall model: Advantages: • Disciplined approach • Careful checking by the Software Quality Assurance Group at the end of each phase. • Testing in each phase. • Documentation available at the end of each phase. Waterfall model problems: • It is difficult to respond to changing customer requirements. • Therefore, this model is only 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. • The customer must have patience. A working version of the program will not be available until late in the project time-span • Feedback from one phase to another might be too late and hence expensive. The Prototyping Models: • Often, a customer defines a set of general objectives for software but does not identify detailed input, processing, or output requirements. • In other cases, the developer may be unsure of the efficiency of an algorithm, the adaptability of an operating system, or the form that human –machine interaction should take • In this case prototyping paradigm may offer the best approach • Requirements gathering • Quick design • Prototype building • Prototype evaluation by customers • Prototype may be refined



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Einstein College of Engineering

Prototype thrown away and software developed using formal process{ it is used to define the requirement} Prototyping Strengths: • Requirements can be set earlier and more reliably •...
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