Utilizing a rotating randomly accessible mass storage medium as a caching device for another rotating mass storage medium
AssigneeSun Microsystems, Inc.
InventorBilly J. Fuller
Life of this patent
Estimating the term…
Abstract
A computer memory system and method utilizes a disk drive as a caching device to overcome the size and cost limitations of conventional semiconductor cache memory. Despite providing somewhat slower access times than semiconductor cache memory, utilizing one or more disk drives as a caching device allows enhanced performance to be maintained for longer times under sustained loads by effectively decreasing the latency of the primary storage device, combining relatively small random requests into larger sequential requests, balancing the input/output ("I/O") load over several disk devices and/or canceling duplicate writes.
Claims25
A method for caching data in a computer system comprising the steps of:
- providing at least one primary computer mass storage device for maintaining system data;
- providing at least one rotating randomly accessible data caching device associated with said at least one primary computer mass storage device for maintaining at least a portion of said system data as cache data, wherein said caching device has substantially similar I/O performance as said primary computer mass storage device;
- providing for reading at least a portion of said cache data from said caching device when said computer system requests access to selected data comprising a subset of said cache data;
- providing for alternatively reading at least some of said system data from said primary computer mass storage device when said computer system requests access to said selected data not comprising a subset of said cache data;
- and
- providing for writing said at least some of said system data to said caching device from said primary computer mass storage device.
A computer program product embodied on:
- a computer usable medium having computer readable code embodied therein for causing caching of data in a computer system having at least one primary computer mass storage device for maintaining system data and at least one rotating randomly accessible data caching device associated with said at least one primary computer mass storage device for further maintaining at least a portion of said system data as cache data, wherein said caching device has substantially similar I/O performance as said primary computer mass storage device, the computer program product comprising:
- computer readable program code devices configured to cause a computer to effect reading at least a portion of said cache data from said caching device when said computer system requests access to selected data comprising a subset of said cache data;
- computer readable program code devices configured to cause a computer to effect alternatively reading at least some of said system data from said primary computer mass storage device when said computer system requests access to said selected data not comprising a subset of said cache data;
- and
- computer readable program code devices configured to cause a computer to effect writing said at least some of said system data to said caching device from said primary computer mass storage device.
A computer system comprising:
- a storage controller;
- a primary computer mass storage device for maintaining system data, said primary mass storage device comprising a disk drive, wherein said system data is organized so as to require relatively small random I/O requests;
- at least one caching device associated with said at least one primary computer mass storage device for maintaining at least a portion of said system data as cache data, said caching device comprising a disk drive wherein said portion of said system data is organized to support relatively larger sequential requests.
Dependencies are inferred from the claim text.