This is an alternative to the first-come first-served (FCFS) algorithm. The drive maintains an incoming buffer of requests, and tied with each request is a cylinder number of the request. Lower cylinder numbers indicate that the cylinder is closer to the spindle, while higher numbers indicate the cylinder is farther away. The shortest seek first algorithm determines which request is closest to the current position of the head, and then services that request next.
Analysisedit
The shortest seek first algorithm has the benefit of simplicity, in that overall arm movement is reduced, resulting in a lower average response time.
However, since the buffer is always getting new requests, these can skew the service time of requests that may be farthest away from the disk head's current location, if the new requests are all close to the current location; in fact, starvation may result, with the faraway requests never being able to make progress.[1]
The elevator algorithm is one alternative for reducing arm movement and response time, and ensuring consistent servicing of requests.
Referencesedit
^Andrew S. Tanenbaum; Herbert Bos (2015). Modern Operating Systems. Pearson. ISBN978-0-13-359162-0.
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shortest, seek, first, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, apri. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Shortest seek first news newspapers books scholar JSTOR April 2021 Learn how and when to remove this message Shortest seek first or shortest seek time first is a secondary storage scheduling algorithm to determine the motion of the disk read and write head in servicing read and write requests Description editThis is an alternative to the first come first served FCFS algorithm The drive maintains an incoming buffer of requests and tied with each request is a cylinder number of the request Lower cylinder numbers indicate that the cylinder is closer to the spindle while higher numbers indicate the cylinder is farther away The shortest seek first algorithm determines which request is closest to the current position of the head and then services that request next Analysis editThe shortest seek first algorithm has the benefit of simplicity in that overall arm movement is reduced resulting in a lower average response time However since the buffer is always getting new requests these can skew the service time of requests that may be farthest away from the disk head s current location if the new requests are all close to the current location in fact starvation may result with the faraway requests never being able to make progress 1 The elevator algorithm is one alternative for reducing arm movement and response time and ensuring consistent servicing of requests References edit Andrew S Tanenbaum Herbert Bos 2015 Modern Operating Systems Pearson ISBN 978 0 13 359162 0 nbsp This computing article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Shortest seek first amp oldid 1166252758, wikipedia, wiki, book, books, library,
