US5706467A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sequential cache management system utilizing the establishment of a microcache and managing the contents of such according to a threshold comparison
Assignee: EMC Corp
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Filing: 1995-09-05
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Granted: 1998-01-06
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Expires: 2015-09-05
Abstract
Abstract A shared system memory buffers data transfers between a plurality of host computers and a plurality of data storage devices. Management of the system memory includes establishing a replacement queue to facilitate performance. When a sequential operation is to be performed, the average fall through time of the data elements in the replacement queue is compared to a constant to determine the stress on the cache. If the cache is stressed, cache management establishes a microcache within the replacement cache. The microcache is used to stage data elements for the sequential operations and replaces data elements on a least recently used basis.
Inventors
- 👤 Natan Vishlitzky
- 👤 Yuval Ofek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:17
CPC Classifications
G; G06; G06F; G06F12/00; G06F12/02; G06F12/08; G06F12/12; G06F12/121; G06F12/123; G06F12/0802; G06F12/0866; G06F12/0871; G06F12/0806; G06F12/084
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
115 words
In a data storage system, the method for staging data elements in a sequential process comprising the steps of: identifying a sequential process, creating a microcache within a data replacement queue for storing the data elements provided by the sequential process when the occurrence of a sequential process is identified, comparing the average fall through time for data elements in the replacement queue to a predetermined threshold to determine whether the replacement queue is stressed, if the replacement queue is determined to be stressed, utilizing the microcache for staging all data elements identified by the sequential process; and, if the replacement queue is determined not to be stressed, disregarding utilization of the microcache for staging.
Claim 2
Dependent Claim
115 words
In a data storage system, the method for staging data elements in a sequential process comprising the steps of: identifying a sequential process, creating a microcache within a data replacement queue for storing the data elements provided by the sequential process when the occurrence of a sequential process is identified, comparing the average fall through time for data elements in the replacement queue to a predetermined threshold to determine whether the replacement queue is stressed, if the replacement queue is determined to be stressed, utilizing the microcache for staging all data elements identified by the sequential process; and, if the replacement queue is determined not to be stressed, disregarding utilization of the microcache for staging.
Claim 3
Dependent Claim
26 words
The method of claim 1 in which that replacement queue determined to be stressed when the average fall through time is less than a predetermined threshold.
Claim 4
Dependent Claim
44 words
The method of claim 2, and further including the step of identifying the least recently used data element in the microcache if the replacement queue is stressed and servicing sequential operations by microcache by replacing the least recently used data element in the microcache.
Claim 5
Dependent Claim
33 words
The method as defined in claim 3 and further including the steps of: servicing the sequential process in the replacement queue if the average fall through time is more than the predetermined threshold.
Claim 6
Dependent Claim
48 words
The method as defined in claim 3 and further including the step of: servicing the sequential process in the replacement queue if the average fall through time is more than the predetermined threshold and the cache slot number of the data element is absent from the cache memory.
Claim 7
Dependent Claim
34 words
The method as defined in claim 3 and further including: establishing the size of the microcache, and incrementing the cache slots within the microcache with the sequential data elements provided by the sequential process.
Claim 8
Dependent Claim
53 words
The method as defined in claim 3 and further including: modifying the established size of the microcache in response to the number of accesses to the data elements in the microcache, and prefetching from said storage devices a plurality of sequential data elements as determined by the stride size of the sequential operation.
Claim 9
Dependent Claim
83 words
The method as defined in claim 3 and further including: updating the cache directory to identify the pointer for the first data element of the sequential process prior to determining the stress on said replacement queue, and modifying the cache directory to identify the pointer for the first data element of the sequential process prior to determining the stress on said replacement queue, and modifying the cache directory to identify a new pointer for the last data element serviced during the sequential operation.
Claim 10
Dependent Claim
128 words
A data storage system comprising: a plurality of host computers and a plurality of data storage devices, a system memory coupled to said host computers and said storage devices for storing data elements provided by said host computers, said system memory comprising; a cache memory for storing data elements from either the host computers or the data storage devices, a replacement queue within said memory for ordering information stored in said cache memory, said replacement queue further including a microcache for responding to sequential operations, and a cache manager for sensing a sequential operation and for establishing a microcache when a sequential operation occurs, said cache manager sensing when said replacement queue is stressed and servicing said sequential operations from said microcache when said replacement queue is stressed.
Claim 11
Dependent Claim
128 words
A data storage system comprising: a plurality of host computers and a plurality of data storage devices, a system memory coupled to said host computers and said storage devices for storing data elements provided by said host computers, said system memory comprising; a cache memory for storing data elements from either the host computers or the data storage devices, a replacement queue within said memory for ordering information stored in said cache memory, said replacement queue further including a microcache for responding to sequential operations, and a cache manager for sensing a sequential operation and for establishing a microcache when a sequential operation occurs, said cache manager sensing when said replacement queue is stressed and servicing said sequential operations from said microcache when said replacement queue is stressed.
Claim 12
Dependent Claim
56 words
The system as defined in claim 8 and further including a comparator for comparing the average fall through time of data elements in said replacement cache to a predetermined threshold, said cache manager in response to said comparator indicating said replacement queue is stress replacing data elements on a least recently used basis in said microcache.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-01-05 | 2001-07-07 | 2002-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-01-05 | 2005-07-07 | 2006-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-01-05 | 2009-07-07 | 2010-01-06 | $7700.00 | Window Closed / Lapsed |