Four Laws of Advanced Software Engineering and System Methodologies

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Please note that file name and page numbers are automatically printed in the footer please do not alter in anyway. Assignment 1

Glass’s law: is the process that determines the properties a particular System should have. The requirements process generates the
Information on which the design will be based . Requirement determines Where a system is to be used, by whom, and what services it should provide. It has paramount important to determine what trade-offs can be made in case of Conflicting requirement. Improper, incomplete or erroneous definition of requirement cause problems in many projects the reasons behind incomplete definition are different needs of different users groups , natural conflicts of interest and difficulty in prioritization among the conflicting

Boehm’s first law: the requirements definition and design has most errors and design error less serious than requirement errors. Identifying these errors in early stage of development is difficult unless developer knows the correct domain of work and in most of the case the errors in requirement definitions and design are detected during the installation stage. removing these error at the later stage of software development is costly since cost for change in the system grow as the development cycle proceeds the subsequent investments are based on decisions made before and number of people affected and involve in error removal might grow from less than ten to exponentially one of the example of implementation errors occur for Fortran programs in an aerospace application where the design was done by people with good domain knowledge which in turn increase the cost of error removal .

Davis law: Models are very useful from to describe systems they are an intellectual concept, but can be transformed in a visible representation, model study the static structure of the system objects use the logical structure of the data and dynamic structure of the tasks and processes. Models are indirect views or abstractions leaving out those things that are not important. It improves the conceptual knowledge, most user do not need them. Davis study was based on qualitative using subjective rather than objective criteria. For example automating a book distribution company: including ordering, shipment, accounting; possibly human resources, payroll, inventory, conveyor, belts and robots to move book. Using several different approaches like object oriented analysis and function oriented analysis and different aspects are emphasized by each approach. As such different tools should be used for different types of job.

Waterfall methodology
The waterfall method is a variation of the systems development life cycle model used in software engineering. It’s a classical approach to linear and sequential approach to software design. Each stage of the waterfall method has distinct goals and once those goals are met the development moves on the major drawback of this model is once a stage has been completed there is no going back to previous stage. Each stage can be designated to a separate team allowing for greater control on the project, the whole process can have deadlines set for each stage which enable to deliver the project on time. Water fall model establishing following stages Requirements, to design creation, to program implementation, to system test, to release to customer .The waterfall model had little or no feedback between stages.

Requirements Phase consists of analysing the problem or need for which the software is being developed and specifies requirements, stating what the software must do. In addition to stated requirements, requirements are derived from higher-level requirements and statements of need.

Design Phase the software structure is defined. Technical approaches are chosen and problems are solved conceptually the two design phase, preliminary design the initial software...
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