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Lehman's Laws Of Software Evolution
In software engineering, the laws of software evolution refer to a series of laws that Lehman and Belady formulated starting in 1974 with respect to software evolution. The laws describe a balance between forces driving new developments on one hand, and forces that slow down progress on the other hand. Over the past decades the laws have been revised and extended several times. Context Observing that most software is subject to change in the course of its existence, the authors set out to determine laws that these changes will typically obey, or must obey in order for the software to survive. In his 1980 article, Lehman qualified the application of such laws by distinguishing between three categories of software: * An ''S''-program is written according to an exact specification of what that program can do. For example the eight queens problem. They are mostly static and shouldn't evolve much. * A ''P''-program is written to implement certain procedures that completely determine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Engineering
Software engineering is a systematic engineering approach to software development. A software engineer is a person who applies the principles of software engineering to design, develop, maintain, test, and evaluate computer software. The term '' programmer'' is sometimes used as a synonym, but may also lack connotations of engineering education or skills. Engineering techniques are used to inform the software development process which involves the definition, implementation, assessment, measurement, management, change, and improvement of the software life cycle process itself. It heavily uses software configuration management which is about systematically controlling changes to the configuration, and maintaining the integrity and traceability of the configuration and code throughout the system life cycle. Modern processes use software versioning. History Beginning in the 1960s, software engineering was seen as its own type of engineering. Additionally, the development of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meir Manny Lehman
Meir "Manny" Lehman, FREng (24 January 1925 – 29 December 2010) was a professor in the School of Computing Science at Middlesex University. From 1972 to 2002 he was a Professor and Head of the Computing Department at Imperial College London. His research contributions include the early realisation of the software evolution phenomenon and the eponymous Lehman's laws of software evolution. Career Lehman was born in Germany on 24 January 1925 and emigrated to England in 1931. He studied mathematics as an undergraduate at Imperial College London where he was involved in the design of the Imperial College Computing Engine's Digital Computer Arithmetic Unit. He spent a year at Ferranti in London before working at Israel's Ministry of Defense from 1957 to 1964. From 1964 to 1972 he worked at IBM's research division in Yorktown Heights, NY where he studied program evolution with Les Belady. The study of IBM's programming process gave the foundations for Lehman's laws of software e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Evolution
Software evolution is the continual development of a piece of software after its initial release to address changing stakeholder and/or market requirements. Software evolution is important because organizations invest large amounts of money in their software and are completely dependent on this software. Software evolution helps software adapt to changing businesses requirements, fix defects, and integrate with other changing systems in a software system environment. General introduction Fred Brooks, in his key book ''The Mythical Man-Month'', states that over 90% of the costs of a typical system arise in the maintenance phase, and that any successful piece of software will inevitably be maintained. In fact, Agile methods stem from maintenance-like activities in and around web based technologies, where the bulk of the capability comes from frameworks and standards. Software maintenance addresses bug fixes and minor enhancements, while software evolution focuses on adaptation an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invariant Work Rate
Invariant and invariance may refer to: Computer science * Invariant (computer science), an expression whose value doesn't change during program execution ** Loop invariant, a property of a program loop that is true before (and after) each iteration * A data type in method overriding that is neither covariant nor contravariant * Class invariant, an invariant used to constrain objects of a class Physics, mathematics, and statistics * Invariant (mathematics), a property of a mathematical object that is not changed by a specific operation or transformation ** Rotational invariance, the property of function whose value does not change when arbitrary rotations are applied to its argument ** Scale invariance, a property of objects or laws that do not change if scales of length, energy, or other variables, are multiplied by a common factor ** Topological invariant * Invariant (physics), something does not change under a transformation, such as from one reference frame to another * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incremental Growth
Increment or incremental may refer to: *Incrementalism, a theory (also used in politics as a synonym for gradualism) *Increment and decrement operators, the operators ++ and -- in computer programming *Incremental computing *Incremental backup, which contain only that portion that has changed since the preceding backup copy. *Increment, chess term for additional time a chess player receives on each move *Incremental games * Increment in rounding See also * * *1+1 (other) 1+1 is a mathematical expression that evaluates to: * 2 (number) (in ordinary arithmetic) * 1 (number) (in Boolean algebra with a notation where '+' denotes a logical disjunction) * 0 (number) (in Boolean algebra with a notation where '+' denotes ... {{Disambiguation da:Inkrementel fr:Incrémentation nl:Increment ja:インクリメント pl:Inkrementacja ru:Инкремент sr:Инкремент sv:++ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |