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Aging (scheduling)
In computer science for Operating systems, aging (US English) or ageing is a Scheduling (computing), scheduling technique used to avoid Resource starvation, starvation. Scheduling (computing)#Fixed priority pre-emptive scheduling, Fixed priority scheduling is a scheduling discipline, in which Task (computing), tasks queued for utilizing a system resource are assigned a priority each. A task with a high priority is allowed to access a specific system resource before a task with a lower priority is allowed to do the same. A disadvantage of this approach is that tasks assigned with a lower priority may be starved when a large number of high priority tasks are queued. Aging is used to gradually increase the Scheduling (computing), priority of a task, based on its waiting time in the Multilevel feedback queue, ready queue. Problem In priority-based Scheduling (computing), scheduling algorithms, a major problem is indefinite block, or Starvation (computing), starvation. A process that is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Science
Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, applied disciplines (including the design and implementation of Computer architecture, hardware and Software engineering, software). Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and preventing security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Programming language theory considers different ways to describe computational processes, and database theory concerns the management of re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for efficient use of the system and may also include accounting software for cost allocation of Scheduling (computing), processor time, mass storage, peripherals, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computerfrom cellular phones and video game consoles to web servers and supercomputers. , Android (operating system), Android is the most popular operating system with a 46% market share, followed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scheduling (computing)
In computing, scheduling is the action of assigning resources to perform tasks. The resources may be processors, network links or expansion cards. The tasks may be threads, processes or data flows. The scheduling activity is carried out by a mechanism called a scheduler. Schedulers are often designed so as to keep all computer resources busy (as in load balancing), allow multiple users to share system resources effectively, or to achieve a target quality-of-service. Scheduling is fundamental to computation itself, and an intrinsic part of the execution model of a computer system; the concept of scheduling makes it possible to have computer multitasking with a single central processing unit (CPU). Goals A scheduler may aim at one or more goals, for example: * maximizing '' throughput'' (the total amount of work completed per time unit); * minimizing '' wait time'' (time from work becoming ready until the first point it begins execution); * minimizing '' latency'' o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resource Starvation
In computer science, resource starvation is a problem encountered in concurrent computing where a process is perpetually denied necessary resources ''Resource'' refers to all the materials available in our environment which are Technology, technologically accessible, Economics, economically feasible and Culture, culturally Sustainability, sustainable and help us to satisfy our needs and want ... to process its work. Starvation may be caused by errors in a scheduling or mutual exclusion algorithm, but can also be caused by resource leaks, and can be intentionally caused via a denial-of-service attack such as a fork bomb. When starvation is impossible in a concurrent algorithm, the algorithm is called starvation-free, lockout-freed or said to have finite bypass. This property is an instance of liveness, and is one of the two requirements for any mutual exclusion algorithm; the other being correctness. The name "finite bypass" means that any process (concurrent part) of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Task (computing)
In computers, computing, a task is a unit of execution (computing), execution or a unit of work. The term is ambiguous; precise alternative terms include ''process (computing), process'', light-weight process, ''thread (computing), thread'' (for execution), ''step'', ''request–response, request'', or ''query'' (for work). In the adjacent diagram, there are task queue, queues of incoming work to do and outgoing completed work, and a thread pool of threads to perform this work. Either the work units themselves or the threads that perform the work can be referred to as "tasks", and these can be referred to respectively as requests/responses/threads, incoming tasks/completed tasks/threads (as illustrated), or requests/responses/tasks. Terminology In the sense of "unit of execution", in some operating systems, a task is synonymous with a process (computing), process, and in others with a thread (computing), thread. In non-interactive execution (batch processing), a task is a unit o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multilevel Feedback Queue
In computer science, a multilevel feedback queue is a scheduling algorithm. Scheduling algorithms are designed to have some process running at all times to keep the central processing unit A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary Processor (computing), processor in a given computer. Its electronic circuitry executes Instruction (computing), instructions ... (CPU) busy. The multilevel feedback queue extends standard algorithms with the following design requirements: #Separate processes into multiple ''ready queues'' based on their need for the processor. #Give preference to processes with short CPU bursts. #Give preference to processes with high I/O bursts. (I/O bound processes will sleep in the ''wait queue'' to give other processes CPU time.) The multilevel feedback queue was first developed by Fernando J. Corbató (1962). For this accomplishment, the Association for Computing Machinery awarded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starvation (computing)
In computer science, resource starvation is a problem encountered in concurrent computing where a process is perpetually denied necessary resources ''Resource'' refers to all the materials available in our environment which are Technology, technologically accessible, Economics, economically feasible and Culture, culturally Sustainability, sustainable and help us to satisfy our needs and want ... to process its work. Starvation may be caused by errors in a scheduling or mutual exclusion algorithm, but can also be caused by resource leaks, and can be intentionally caused via a denial-of-service attack such as a fork bomb. When starvation is impossible in a concurrent algorithm, the algorithm is called starvation-free, lockout-freed or said to have finite bypass. This property is an instance of liveness, and is one of the two requirements for any mutual exclusion algorithm; the other being correctness. The name "finite bypass" means that any process (concurrent part) of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
