Browse Prior Art Database

Synchronized Rotating Storage Devices Utilizing Sector Queuing

IP.com Disclosure Number: IPCOM000091175D
Original Publication Date: 1969-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

McGraw, EM: AUTHOR [+2]

Abstract

This system substantially reduces the contention for core storage by synchronizing a plurality of rotating storage devices and dividing the information stored in each track into a plurality of sectors of fixed block length.

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Synchronized Rotating Storage Devices Utilizing Sector Queuing

This system substantially reduces the contention for core storage by synchronizing a plurality of rotating storage devices and dividing the information stored in each track into a plurality of sectors of fixed block length.

The sequential order in which requests are made for data recorded on a rotating storage device, e.g., disk, drum, etc., generally bears no relationship to the actual angular position of the rotating device. It can, therefore, take a complete revolution or a part of a revolution of the device before the desired address is in a position to be read or recorded. Reduction of the latent period, the time it takes the disk to rotate from its actual position to the angular position at which the desired data is located, is accomplished by a technique termed sector queuing. All tracks on the rotating device are divided into a plurality of fixed length data blocks called sectors. A number of information transfer request lists are assembled for each sector. When a request is received, it is placed in the list or queue associated with the sector at which the information transfer is to begin. Enqueuing of storage requests allows the time required for rotation to a newly specified enqueued record to be used for servicing of earlier enqueued requests directed to sectors which are already available.

Each rotating device 10 has a drum drive 12 which is powered from common synchronizer 14. The latter causes devices 10 to rotate at the same angular velocity and phase. Alternatively, devices 10 can be driven from a common sha...