I/O scheduling


I/O scheduling

Input/output (I/O) scheduling is a term used to describe the method computer operating systems decide the order that block I/O operations will be submitted to storage volumes. I/O Scheduling is sometimes called 'disk scheduling'.

Contents

Purpose

I/O schedulers can have many purposes depending on the goal of the I/O scheduler, some common goals are:

  • To minimize time wasted by hard disk seeks.
  • To prioritize a certain processes' I/O requests.
  • To give a share of the disk bandwidth to each running process.
  • To guarantee that certain requests will be issued before a particular deadline.

Implementation

I/O Scheduling usually has to work with hard disks which share the property that there is long access time for requests which are far away from the current position of the disk head (this operation is called a seek). To minimize the effect this has on system performance, most I/O schedulers implement a variant of the elevator algorithm which re-orders the incoming randomly ordered requests into the order in which they will be found on the disk.

Common disk I/O scheduling disciplines

See also

References


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Scheduling (production processes) — Scheduling is an important tool for manufacturing and engineering, where it can have a major impact on the productivity of a process. In manufacturing, the purpose of scheduling is to minimize the production time and costs, by telling a… …   Wikipedia

  • Scheduling — is the process of deciding how to commit resources between a variety of possible tasks. Time can be specified (scheduling a flight to leave at 8:00) or floating as part of a sequence of events.Scheduling may refer to: * I/O scheduling, the order… …   Wikipedia

  • scheduling — UK US /ˈʃedjuːlɪŋ/ US  /ˈskedʒuːlɪŋ/ noun [U] ► TRANSPORT, PRODUCTION, COMMERCE the job or activity of planning the times at which particular tasks will be done or events will happen: »production/work/crew scheduling a scheduling conflict/problem …   Financial and business terms

  • Scheduling coordinator —   Scheduling coordinators (SCs) submit balanced schedules and provide settlement ready meter data to the ISO. Scheduling coordinators also:   • Settle with generators and retailers, the PX and the ISO   • Maintain a year round, 24 hour scheduling …   Energy terms

  • scheduling — index codification, economy (frugality) Burton s Legal Thesaurus. William C. Burton. 2006 …   Law dictionary

  • Scheduling (computing) — This article is about processes assignment in operating systems. For other uses, see Scheduling (disambiguation). Scheduling is a key concept in computer multitasking, multiprocessing operating system and real time operating system designs.… …   Wikipedia

  • Scheduling algorithm — In computer science, a scheduling algorithm is the method by which threads, processes or data flows are given access to system resources (e.g. processor time, communications bandwidth). This is usually done to load balance a system effectively or …   Wikipedia

  • Scheduling — Unter Scheduling (englisch für „Zeitplanerstellung“), auch Zeitablaufsteuerung genannt, versteht man die Erstellung eines Ablaufplanes (schedule), der Prozessen zeitlich begrenzt Ressourcen zuweist (Allokation). Scheduling findet hauptsächlich in …   Deutsch Wikipedia

  • Scheduling (Informatik) — Ein Prozess Scheduler (Scheduler = Steuerprogramm) ist eine Arbitrationslogik, der die zeitliche Ausführung mehrerer Prozesse in Betriebssystemen regelt. Prozess Scheduler kann man grob in unterbrechende (preemptive) und nicht unterbrechende (non …   Deutsch Wikipedia

  • Scheduling Open Service Interface Definition — The Scheduling Open Service Interface Definition (OSID) is an O.K.I. specification. OSIDs are programmatic interfaces which comprise a Service Oriented Architecture for designing and building reusable and interoperable software.The Scheduling… …   Wikipedia

  • Scheduling alliance — A scheduling alliance is agreement among independent college athletic teams to guarantee a set number of games to each member. Although it is not formally recognized by the governing body (usually the NCAA), it resembles a conference in many… …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.