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EP0757310A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Controlling disk drives

Assignee: HP Inc
•
Filing: 1996-07-19
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Granted: —
•
Expires: 2016-07-19
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Abstract

Abstract A disk control mechanism (771) for controlling the operations of a movable arm disk drive (209) contains a disk access scheduler (109,109') which accepts disk access requests having a deadline and a disk location. The disk access scheduler consists of a queue data structure (301) for storing the requests. The queue contains a predefined window (605) that contains a certain number of requests with deadlines to expire sooner than all other requests. The request that is most soon to expire, the most urgent request, is located at the head of the queue. The disk access scheduler contains logic means (411) to determine whether the most urgent request has a deadline to expire sooner than tolerated by a set threshold, and in such cases the disk access scheduler schedules for service the most urgent request prior to any other request (413), otherwise it scans towards the most urgent request and schedules requests with a disk location between the current arm location and the most urgent request (415).

Inventors

  • 👤 Shenze Chen
  • 👤 Manu Thaper

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-02 20:54
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/06; G06F3/0601; G11; G11B; G11B27/00; G11B27/10; G11B27/102; G11B27/105; H; H04; H04N; H04N7/00; H04N7/16; H04N7/173; H04N7/17309; H04N7/17336; G06F3/0668; G06F3/0671; G06F3/0673

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 191 words
A method of controlling a disk drive (103) with a movable arm (209), wherein said arm (209) at any given point in time has a current location, comprising the steps of: defining a threshold parameter; accepting a plurality of disk access requests, each having a prescribed deadline and a disk address; storing the disk access requests (503) in a queue (301) having a front, such that the disk access request with the earliest deadline is at the front of the queue and such that the queue is sorted according to deadlines; defining a window (605) in said queue (301) wherein said window contains a certain number of disk access requests in the front of said queue; processing requests in said queue by: determining how much time is left before the deadline of the first request in the queue expires (409); if said time is less than the threshold (411), serve the first request (413); otherwise scan from said current location towards the disk address of said first request (415); and during said scan schedule the first encountered request that is in the scan path and that is in the window (415).
Claim 2
Dependent Claim 36 words
The method of Claim 1, wherein said step of determining how much time is left before the deadline of the first request expires comprises comparing the deadline for said first request to the current clock time.
Claim 3
Dependent Claim 19 words
The method of Claim 1 or 2, further comprising the step of defining the size of said window (605).
Claim 4
Dependent Claim 25 words
The method of Claim 1, 2, or 3, wherein subsequent to being serviced a request is removed from said queue and from said window (417).
Claim 5
Dependent Claim 164 words
A disk control mechanism (371) for controlling the operations of a movable arm disk drive (209) wherein at any given point in time, said movable arm has a current location (303), comprising: a disk access scheduler (109, 109') operable to accept disk access requests having a deadline and a disk location, including: a queue data structure (301) for storing said requests, wherein one request is more urgent than any other request in said queue; a window (605) in said queue, wherein said window contains a certain number of requests with deadlines to expire sooner than all other requests; a first logic (411) to determine whether said most urgent request has a deadline to expire sooner than tolerated by a set threshold, and in such cases to service said most urgent request prior to any other request (413), otherwise to scan towards said most urgent request and to schedule any requests with disk locations between said current arm location and said most urgent request (415).

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