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Software Architecture
Software architecture is the fundamental structure of a software system and the discipline of creating such structures and systems. Each structure comprises software elements, relations among them, and properties of both elements and relations. The ''architecture'' of a software system is a metaphor, analogous to the architecture of a building. It functions as a blueprint for the system and the developing project, which project management can later use to extrapolate the tasks necessary to be executed by the teams and people involved. Software architecture is about making fundamental structural choices that are costly to change once implemented. Software architecture choices include specific structural options from possibilities in the design of the software. For example, the systems that controlled the Space Shuttle launch vehicle had the requirement of being very fast and very reliable. Therefore, an appropriate real-time computing language would need to be chosen. Additiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software System
A software system is a system of intercommunicating components based on software forming part of a computer system (a combination of hardware and software). It "consists of a number of separate programs, configuration files, which are used to set up these programs, system documentation, which describes the structure of the system, and user documentation, which explains how to use the system". The term "software system" should be distinguished from the terms "computer program" and "software". The term computer program generally refers to a set of instructions ( source, or object code) that perform a specific task. However, a software system generally refers to a more encompassing concept with many more components such as specification, test results, end-user documentation, maintenance records, etc.' The use of the term software system is at times related to the application of systems theory approaches in the context of software engineering. A software system consists of seve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quality Attributes
In systems engineering and requirements engineering, a non-functional requirement (NFR) is a requirement that specifies criteria that can be used to judge the operation of a system, rather than specific behaviours. They are contrasted with functional requirements that define specific behavior or functions. The plan for implementing ''functional'' requirements is detailed in the system ''design''. The plan for implementing ''non-functional'' requirements is detailed in the system ''architecture'', because they are usually architecturally significant requirements. Definition Broadly, functional requirements define what a system is supposed to ''do'' and non-functional requirements define how a system is supposed to ''be''. Functional requirements are usually in the form of "system shall do ", an individual action or part of the system, perhaps explicitly in the sense of a mathematical function, a black box description input, output, process and control functional model or ... [...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 ... [...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 teac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Architectural Pattern
An architectural pattern is a general, reusable solution to a commonly occurring problem in software architecture within a given context. The architectural patterns address various issues in software engineering, such as computer hardware performance limitations, high availability and minimization of a business risk. Some architectural patterns have been implemented within software frameworks. The use of the word "pattern" in the software industry was influenced by similar concepts as expressed in traditional architecture, such as Christopher Alexander's '' A Pattern Language'' (1977) which discussed the practice in terms of establishing a pattern lexicon, prompting the practitioners of computer science to contemplate their own design lexicon. Usage of this metaphor within the software engineering profession became commonplace after the publication of ''Design Patterns'' (1994) by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides—now commonly known as the "G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reference Architecture
A reference architecture in the field of software architecture or enterprise architecture provides a template solution for an architecture for a particular domain. It also provides a common vocabulary with which to discuss implementations, often with the aim to stress commonality. A software reference architecture is a software architecture where the structures and respective elements and relations provide templates for concrete architectures in a particular domain or in a family of software systems. A reference architecture often consists of a list of functions and some indication of their interfaces (or APIs) and interactions with each other and with functions located outside of the scope of the reference architecture. Reference architectures can be defined at different levels of abstraction. A highly abstract one might show different pieces of equipment on a communications network, each providing different functions. A lower level one might demonstrate the interactions of pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-functional Requirements
In systems engineering and requirements engineering, a non-functional requirement (NFR) is a requirement that specifies criteria that can be used to judge the operation of a system, rather than specific behaviours. They are contrasted with functional requirements that define specific behavior or functions. The plan for implementing ''functional'' requirements is detailed in the system ''design''. The plan for implementing ''non-functional'' requirements is detailed in the system ''architecture'', because they are usually architecturally significant requirements. Definition Broadly, functional requirements define what a system is supposed to ''do'' and non-functional requirements define how a system is supposed to ''be''. Functional requirements are usually in the form of "system shall do ", an individual action or part of the system, perhaps explicitly in the sense of a mathematical function, a black box description input, output, process and control functional model or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Requirements
In product development and process optimization, a requirement is a singular documented physical or functional need that a particular design, product or process aims to satisfy. It is commonly used in a formal sense in engineering design, including for example in systems engineering, software engineering, or enterprise engineering. It is a broad concept that could speak to any necessary (or sometimes desired) function, attribute, capability, characteristic, or quality of a system for it to have value and utility to a customer, organization, internal user, or other stakeholder. Requirements can come with different levels of specificity; for example, a requirement specification or requirement "spec" (often imprecisely referred to as "the" spec/specs, but there are actually different sorts of specifications) refers to an explicit, highly objective/clear (and often quantitative) requirement (or sometimes, ''set'' of requirements) to be satisfied by a material, design, product, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ilities
In systems engineering and requirements engineering, a non-functional requirement (NFR) is a requirement that specifies criteria that can be used to judge the operation of a system, rather than specific behaviours. They are contrasted with functional requirements that define specific behavior or functions. The plan for implementing ''functional'' requirements is detailed in the system ''design''. The plan for implementing ''non-functional'' requirements is detailed in the system ''architecture'', because they are usually architecturally significant requirements. Definition Broadly, functional requirements define what a system is supposed to ''do'' and non-functional requirements define how a system is supposed to ''be''. Functional requirements are usually in the form of "system shall do ", an individual action or part of the system, perhaps explicitly in the sense of a mathematical function, a black box description input, output, process and control functional model or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Availability
In reliability engineering, the term availability has the following meanings: * The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at an unknown, ''i.e.'' a random, time. * The probability that an item will operate satisfactorily at a given point in time when used under stated conditions in an ideal support environment. Normally high availability systems might be specified as 99.98%, 99.999% or 99.9996%. Representation The simplest representation of availability (''A'') is a ratio of the expected value of the uptime of a system to the aggregate of the expected values of up and down time (that results in the "total amont of time" ''C'' of the observation window) : A = \frac = \frac Another equation for availability (''A'') is a ratio of the Mean Time To Failure (MTTF) and Mean Time To Repair (MTTR), or : A = \frac = \frac If we define the status function X(t) as : X ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maintainability
In engineering, maintainability is the ease with which a product can be maintained to: * correct defects or their cause, * Repair or replace faulty or worn-out components without having to replace still working parts, * prevent unexpected working conditions, * maximize a product's useful life, * maximize efficiency, reliability, and safety, * meet new requirements, * make future maintenance easier, or * cope with a changing environment. In some cases, maintainability involves a system of continuous improvement - learning from the past to improve the ability to maintain systems, or improve the reliability of systems based on maintenance experience. In telecommunication and several other engineering fields, the term maintainability has the following meanings: * A characteristic of design and installation, expressed as the probability that an item will be retained in or restored to a specified condition within a given period of time, when the maintenance is performed by prescribe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reliability (engineering)
Reliability engineering is a sub-discipline of systems engineering that emphasizes the ability of equipment to function without failure. Reliability describes the ability of a system or component to function under stated conditions for a specified period of time. Reliability is closely related to availability, which is typically described as the ability of a component or system to function at a specified moment or interval of time. The reliability function is theoretically defined as the probability of success at time t, which is denoted R(t). This probability is estimated from detailed (physics of failure) analysis, previous data sets or through reliability testing and reliability modelling. Availability, testability, maintainability and maintenance are often defined as a part of "reliability engineering" in reliability programs. Reliability often plays the key role in the cost-effectiveness of systems. Reliability engineering deals with the prediction, prevention and manageme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
