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Banker's Algorithm
Banker's algorithm, sometimes referred to as the detection algorithm, is a resource allocation and deadlock avoidance algorithm developed by Edsger Dijkstra that tests for safety by simulating the allocation of predetermined maximum possible amounts of all resources, and then makes an "s-state" check to test for possible deadlock conditions for all other pending activities, before deciding whether allocation should be allowed to continue. The algorithm was developed in the design process for the THE operating system and originally described (in Dutch) in EWD108. When a new process enters a system, it must declare the maximum number of instances of each resource type that it may ever claim; clearly, that number may not exceed the total number of resources in the system. Also, when a process gets all its requested resources it must return them in a finite amount of time. Resources For the Banker's algorithm to work, it needs to know three things: *How much of each resource each p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resource Allocation
In economics, resource allocation is the assignment of available resources to various uses. In the context of an entire economy, resources can be allocated by various means, such as markets, or planning. In project management, resource allocation or resource management is the scheduling of activities and the resources required by those activities while taking into consideration both the resource availability and the project time. Economics In economics, the field of public finance deals with three broad areas: macroeconomic stabilization, the distribution of income and wealth, and the allocation of resources. Much of the study of the allocation of resources is devoted to finding the conditions under which particular mechanisms of resource allocation lead to Pareto efficient outcomes, in which no party's situation can be improved without hurting that of another party. Strategic planning In strategic planning, resource allocation is a plan for using available resources, for exampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deadlock
In concurrent computing, deadlock is any situation in which no member of some group of entities can proceed because each waits for another member, including itself, to take action, such as sending a message or, more commonly, releasing a lock. Deadlocks are a common problem in multiprocessing systems, parallel computing, and distributed systems, because in these contexts systems often use software or hardware locks to arbitrate shared resources and implement process synchronization. In an operating system, a deadlock occurs when a process or thread enters a waiting state because a requested system resource is held by another waiting process, which in turn is waiting for another resource held by another waiting process. If a process remains indefinitely unable to change its state because resources requested by it are being used by another process that itself is waiting, then the system is said to be in a deadlock. In a communications system, deadlocks occur mainly due t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specifications for performing calculations and data processing. More advanced algorithms can perform automated deductions (referred to as automated reasoning) and use mathematical and logical tests to divert the code execution through various routes (referred to as automated decision-making). Using human characteristics as descriptors of machines in metaphorical ways was already practiced by Alan Turing with terms such as "memory", "search" and "stimulus". In contrast, a Heuristic (computer science), heuristic is an approach to problem solving that may not be fully specified or may not guarantee correct or optimal results, especially in problem domains where there is no well-defined correct or optimal result. As an effective method, an algorithm ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edsger Dijkstra
Edsger Wybe Dijkstra ( ; ; 11 May 1930 – 6 August 2002) was a Dutch computer scientist, programmer, software engineer, systems scientist, and science essayist. He received the 1972 Turing Award for fundamental contributions to developing programming languages, and was the Schlumberger Centennial Chair of Computer Sciences at The University of Texas at Austin from 1984 until 2000. Shortly before his death in 2002, he received the ACM PODC Influential Paper Award in distributed computing for his work on self-stabilization of program computation. This annual award was renamed the Dijkstra Prize the following year, in his honor. Biography Early years Edsger W. Dijkstra was born in Rotterdam. His father was a chemist who was president of the Dutch Chemical Society; he taught chemistry at a secondary school and was later its superintendent. His mother was a mathematician, but never had a formal job. Dijkstra had considered a career in law and had hoped to represent the Netherlan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resource (computer Science)
In computing, a system resource, or simple resource, is any physical or virtual component of limited availability within a computer system. All connected devices and internal system components are resources. Virtual system resources include files (concretely file handles), network connections (concretely network sockets), and memory areas. Managing resources is referred to as resource management, and includes both preventing resource leaks (not releasing a resource when a process has finished using it) and dealing with resource contention (when multiple processes wish to access a limited resource). Computing resources are used in cloud computing to provide services through networks. Major resource types * Interrupt request (IRQ) lines * Direct memory access (DMA) channels * Port-mapped I/O * Memory-mapped I/O * Locks * External devices * External memory or objects, such as memory managed in native code, from Java; or objects in the Document Object Model (DOM), from JavaSc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
THE (operating System)
The THE multiprogramming system or THE OS was a computer operating system designed by a team led by Edsger W. Dijkstra, described in monographs in 1965-66 (Jun 14, 1965) and published in 1968. Dijkstra never named the system; "THE" is simply the abbreviation of "Technische Hogeschool Eindhoven", then the name (in Dutch) of the Eindhoven University of Technology of the Netherlands. The THE system was primarily a batch system that supported multitasking; it was not designed as a multi-user operating system. It was much like the SDS 940, but "the set of processes in the THE system was static". The THE system apparently introduced the first forms of software-based paged virtual memory (the Electrologica X8 did not support hardware-based memory management), freeing programs from being forced to use physical locations on the drum memory. It did this by using a modified ALGOL compiler (the only programming language supported by Dijkstra's system) to "automatically generate ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dutch Language
Dutch ( ) is a West Germanic language spoken by about 25 million people as a first language and 5 million as a second language. It is the third most widely spoken Germanic language, after its close relatives German and English. ''Afrikaans'' is a separate but somewhat mutually intelligible daughter languageAfrikaans is a daughter language of Dutch; see , , , , , . Afrikaans was historically called Cape Dutch; see , , , , , . Afrikaans is rooted in 17th-century dialects of Dutch; see , , , . Afrikaans is variously described as a creole, a partially creolised language, or a deviant variety of Dutch; see . spoken, to some degree, by at least 16 million people, mainly in South Africa and Namibia, evolving from the Cape Dutch dialects of Southern Africa. The dialects used in Belgium (including Flemish) and in Suriname, meanwhile, are all guided by the Dutch Language Union. In Europe, most of the population of the Netherlands (where it is the only official language spoken country ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deadly Embrace
Deadly may refer to: * Deadliness, the ability to cause death Arts and entertainment * ''Deadly'', a 2011 novel by Julie Chibbaro * ''Deadly'', a children's book series by Morris Gleitzman and Paul Jennings * ''Deadly'' (Australian TV series), an Australian children's television cartoon series * ''Deadly'' (film), a 1991 Australian film * ''Deadly'' (franchise), a British wildlife TV documentary series * Deadly Awards, also known as The Deadlys, awards for excellence given to Indigenous Australians for achievement in music, sport, entertainment and community * ''Karla'' (film), a 2006 American movie originally titled ''Deadly'' Other uses * Alan Dedicoat (born 1954), BBC announcer nicknamed "Deadly" * Deadly, a word in Aboriginal Australian English meaning excellent, similar to "wicked" or "awesome" in English slang See also * Lethal (other) *Deadly Nannas, Australian singing group *Uncle Deadly (Muppet), a Muppets character * "Too Deadly", an episode of ''Wapos Ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory (computers)
In computing, memory is a device or system that is used to store information for immediate use in a computer or related computer hardware and digital electronic devices. The term ''memory'' is often synonymous with the term ''primary storage'' or ''main memory''. An archaic synonym for memory is store. Computer memory operates at a high speed compared to storage that is slower but less expensive and higher in capacity. Besides storing opened programs, computer memory serves as disk cache and write buffer to improve both reading and writing performance. Operating systems borrow RAM capacity for caching so long as not needed by running software. If needed, contents of the computer memory can be transferred to storage; a common way of doing this is through a memory management technique called ''virtual memory''. Modern memory is implemented as semiconductor memory, where data is stored within memory cells built from MOS transistors and other components on an integrated circui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semaphore (programming)
In computer science, a semaphore is a variable or abstract data type used to control access to a common resource by multiple threads and avoid critical section problems in a concurrent system such as a multitasking operating system. Semaphores are a type of synchronization primitive. A trivial semaphore is a plain variable that is changed (for example, incremented or decremented, or toggled) depending on programmer-defined conditions. A useful way to think of a semaphore as used in a real-world system is as a record of how many units of a particular resource are available, coupled with operations to adjust that record ''safely'' (i.e., to avoid race conditions) as units are acquired or become free, and, if necessary, wait until a unit of the resource becomes available. Semaphores are a useful tool in the prevention of race conditions; however, their use is not a guarantee that a program is free from these problems. Semaphores which allow an arbitrary resource count are calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interface (computer Science)
In computing, an interface is a shared boundary across which two or more separate components of a computer system exchange information. The exchange can be between software, computer hardware, peripheral devices, humans, and combinations of these. Some computer hardware devices, such as a touchscreen, can both send and receive data through the interface, while others such as a mouse or microphone may only provide an interface to send data to a given system. Hardware interfaces Hardware interfaces exist in many components, such as the various buses, storage devices, other I/O devices, etc. A hardware interface is described by the mechanical, electrical, and logical signals at the interface and the protocol for sequencing them (sometimes called signaling). See also: A standard interface, such as SCSI, decouples the design and introduction of computing hardware, such as I/O devices, from the design and introduction of other components of a computing system, thereby allo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concurrency Control Algorithms
Concurrent means happening at the same time. Concurrency, concurrent, or concurrence may refer to: Law * Concurrence, in jurisprudence, the need to prove both ''actus reus'' and ''mens rea'' * Concurring opinion (also called a "concurrence"), a legal opinion which supports the conclusion, though not always the reasoning, of the majority. * Concurrent estate, a concept in property law * Concurrent resolution, a legislative measure passed by both chambers of the United States Congress * Concurrent sentences, in criminal law, periods of imprisonment that are served simultaneously Computing * Concurrency (computer science), the property of program, algorithm, or problem decomposition into order-independent or partially-ordered units * Concurrent computing, the overlapping execution of multiple interacting computational tasks * Concurrence (quantum computing), a measure used in quantum information theory * Concurrent Computer Corporation, an American computer systems manufacturer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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