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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 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fred Brooks
Frederick Phillips Brooks Jr. (April 19, 1931 – November 17, 2022) was an American computer architect, software engineer, and computer scientist, best known for managing the development of IBM's System/360 family of computers and the OS/360 software support package, then later writing candidly about the process in his seminal book ''The Mythical Man-Month''. In 1976, Brooks was elected as a member into the National Academy of Engineering for "contributions to computer system design and the development of academic programs in computer sciences". Brooks received many awards, including the National Medal of Technology in 1985 and the Turing Award in 1999. Education Born on April 19, 1931, in Durham, North Carolina, he attended Duke University, graduating in 1953 with a Bachelor of Science degree in physics, and he received a Ph.D. in applied mathematics (computer science) from Harvard University in 1956, supervised by Howard Aiken. Brooks served as the graduate teaching ... [...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 game Incremental games, also known as clicker games, clicking games (on PCs) or tap games (in mobile games), are video games whose gameplay consists of the player performing simple actions such as clicking on the screen repeatedly. This "grinding" ear ...s * Increment in rounding See also * * * 1+1 (other) {{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] |
Evolution And Process
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on this variation, resulting in certain characteristics becoming more common or more rare within a population. The evolutionary pressures that determine whether a characteristic is common or rare within a population constantly change, resulting in a change in heritable characteristics arising over successive generations. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms, and molecules. The theory of evolution by na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Entropy
Software entropy is the idea that software eventually rots as it is changed if sufficient care is not taken to maintain coherence with product design and established design principles. The common usage is only tangentially related to entropy as defined in classical thermodynamics and statistical physics. Another aspect can be found in what is perceived to be a decay in the quality of otherwise static software that is the result of the inevitable changes to its environment, that often occur as operating systems and other components are upgraded or retired. History A work on software engineering by Ivar Jacobson et al, in 1992 describes software entropy as follows: :''The second law of thermodynamics, in principle, states that a closed system's disorder cannot be reduced, it can only remain unchanged or increase. A measure of this disorder is entropy. This law also seems plausible for software systems; as a system is modified, its disorder, or entropy, tends to increase. This is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baldwinian Evolution
In evolutionary biology, the Baldwin effect, a phenotype-first theory of evolution, describes the effect of learned behaviour on evolution. James Mark Baldwin and others suggested during the eclipse of Darwinism in the late 19th century that an organism's ''ability to learn'' new behaviours (e.g. to acclimatise to a new stressor) will affect its reproductive success and will therefore have an effect on the genetic makeup of its species through natural selection. Though this process appears similar to Lamarckism, that view proposes that living things ''inherited'' their parents' acquired characteristics. The Baldwin effect has been independently proposed several times, and today it is generally recognized as part of the modern synthesis. "A New Factor in Evolution" The effect, then unnamed, was put forward in 1896 in a paper "A New Factor in Evolution" by the American psychologist James Mark Baldwin, with a second paper in 1897. The paper proposed a mechanism for specific select ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamarckian Evolution
Lamarckism, also known as Lamarckian inheritance or neo-Lamarckism, is the notion that an organism can pass on to its offspring physical characteristics that the parent organism acquired through use or disuse during its lifetime. It is also called the inheritance of acquired characteristics or more recently soft inheritance. The idea is named after the French zoologist Jean-Baptiste Lamarck (1744–1829), who incorporated the classical era theory of soft inheritance into his theory of evolution as a supplement to his concept of orthogenesis, a drive towards complexity. Introductory textbooks contrast Lamarckism with Charles Darwin's theory of evolution by natural selection. However, Darwin's book ''On the Origin of Species'' gave credence to the idea of heritable effects of use and disuse, as Lamarck had done, and his own concept of pangenesis similarly implied soft inheritance. Many researchers from the 1860s onwards attempted to find evidence for Lamarckian inheritance, but the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darwinian Evolution
Darwinism is a theory of biological evolution developed by the English naturalist Charles Darwin (1809–1882) and others, stating that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce. Also called Darwinian theory, it originally included the broad concepts of transmutation of species or of evolution which gained general scientific acceptance after Darwin published ''On the Origin of Species'' in 1859, including concepts which predated Darwin's theories. English biologist Thomas Henry Huxley coined the term ''Darwinism'' in April 1860. Terminology Darwinism subsequently referred to the specific concepts of natural selection, the Weismann barrier, or the central dogma of molecular biology. Though the term usually refers strictly to biological evolution, creationists have appropriated it to refer to the origin of life or to cosmic evolution, that ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Dynamics
System dynamics (SD) is an approach to understanding the nonlinear behaviour of complex systems over time using stocks, flows, internal feedback loops, table functions and time delays. Overview System dynamics is a methodology and mathematical modeling technique to frame, understand, and discuss complex issues and problems. Originally developed in the 1950s to help corporate managers improve their understanding of industrial processes, SD is currently being used throughout the public and private sector for policy analysis and design. Convenient graphical user interface (GUI) system dynamics software developed into user friendly versions by the 1990s and have been applied to diverse systems. SD models solve the problem of simultaneity (mutual causation) by updating all variables in small time increments with positive and negative feedbacks and time delays structuring the interactions and control. The best known SD model is probably the 1972 ''The Limits to Growth''. This model f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Source Software Development
Open-source software development (OSSD) is the process by which open-source software, or similar software whose source code is publicly available, is developed by an open-source software project. These are software products available with its source code under an open-source license to study, change, and improve its design. Examples of some popular open-source software products are Mozilla Firefox, Google Chromium, Android, LibreOffice and the VLC media player. History In 1997, Eric S. Raymond wrote ''The Cathedral and the Bazaar''.Raymond, E.S. (1999). ''The Cathedral & the Bazaar''. O'Reilly Retrieved from http://www.catb.org/~esr/writings/cathedral-bazaar/. See also: The Cathedral and the Bazaar. In this book, Raymond makes the distinction between two kinds of software development. The first is the conventional closed-source development. This kind of development method is, according to Raymond, like the building of a cathedral; central planning, tight organization and one proce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
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] |
The Mythical Man-Month
''The Mythical Man-Month: Essays on Software Engineering'' is a book on software engineering and project management by Fred Brooks first published in 1975, with subsequent editions in 1982 and 1995. Its central theme is that adding manpower to a software project that is behind schedule delays it even longer. This idea is known as Brooks's law, and is presented along with the second-system effect and advocacy of prototyping. Brooks's observations are based on his experiences at IBM while managing the development of OS/360. He had added more programmers to a project falling behind schedule, a decision that he would later conclude had, counter-intuitively, delayed the project even further. He also made the mistake of asserting that one project—involved in writing an ALGOL compiler—would require six months, regardless of the number of workers involved (it required longer). The tendency for managers to repeat such errors in project development led Brooks to quip that his book is c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
