International Business Machines Corporation

Other

Globalfoundries Inc.

Clark A Anderson

Adrian Cuenin Gerhard

William J Maitland, Jr

Louise Ann Marier

Daniel Frank Moertl

David Robison Hall

Earl Albert Cunningham

Rick A Weckwerth

John Jeffrey Stephenson

Michael Scott Hicken

Todd Barry Anderson

Lynn Charles Berning

David Navarro

Daniel D Reno

Alice Louise Kub

Gerald Lawrence Cadloni

A first cache of a first IOA is detected storing an amount of data that satisfies a memory shortage threshold. A request for extra memory for the first IOA is transmitted. The request is sent in response to detecting that the first cache stores the amount of data that satisfies the memory shortage threshold. The request is transmitted to a plurality of IOAs of a computer system. A second cache of a second IOA is detected storing an amount of data that satisfies a memory dissemination threshold. Memory of the second cache is allocated to the first cache. The memory is allocated in response to the request and the amount of data in the second cache satisfying the memory dissemination threshold.

Managing memory allocation between input/output adapter caches

A storage subsystem records a copy of a data object on a plurality of storage devices. The storage subsystem receives a read request to read a data object. Under certain utilization conditions of the storage subsystem, a resource utilization condition satisfies a split-read criterion. In response to the resource utilization condition satisfying the split-read criterion, the storage subsystem reads at least a portion of the data object from each of the storage devices having a copy of the data object.

Dynamic optimization of raid read operations

A method, system and memory controller for implementing dynamic enabling and disabling of cache based upon workload in a computer system. Predefined sets of information are monitored while the cache is enabled to identify a change in workload, and selectively disabling the cache responsive to a first identified predefined workload. Monitoring predefined information to identify a second predefined workload while the cache is disabled, and selectively enabling the cache responsive to said identified second predefined workload.

Implementing dynamic cache enabling and disabling based upon workload

A method for prefetching data for a cache memory from a mass-storage device having a controller that executes a plurality of reordered commands. The method includes predetermining an extra time interval for each of the plurality of reordered commands. Next, prior to executing the next reordered command, data located subsequent to data requested from a committed command is prefetched utilizing the predetermined extra time interval of the next command. In a related embodiment, the method includes executing a command reordering algorithm during which the seek and latency time periods of each of the plurality of reordered commands is computed.

Method and system for prefetching data where commands are reordered for execution

In a ultra high density, multiple-disk drive, track switches within a cylinder of tracks as well as track switches to tracks on other cylinders both require a movement of the head stack actuator. Track switching latency in such a disk drive is reduced by overlapping pre-movement portions of the track switching process with the data transfer operation of the currently active recording head. In addition, post-movement portions of the track switching process are overlapped with the movement of the heads so that the next selected read/write head may begin a data transfer operation immediately upon arrival at the next track. Further, the pre-movement and post-movement portions of the track-switch process may be overlapped with low displacement movement of the read/write heads relative to the currently active track or the next track.

Method and apparatus for reducing track switch latency in a disk drive

A method and apparatus are provided for implementing automatic cache variable update. A cache variable update hardware maintains a plurality of variables indicative of a data segment in the cache. The plurality of variables include a segment state variable, a segment starting address variable, a segment length variable and a segment offset variable. The cache variable update hardware monitors the cache to identify a selection of a segment for a data transfer to and from the cache and to identify data transfers. The plurality of variables are initialized responsive to an identified cache search. The segment length variable is incremented responsive to a data block written to the cache. The segment state variable is modified responsive to a data transfer complete.

Method and apparatus for implementing automatic cache variable update

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Rochester, MN, United States of America

Clark A Anderson