Invention Grant
- Patent Title: Efficient access to storage devices with usage bitmaps
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Application No.: US13906778Application Date: 2013-05-31
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Publication No.: US08947988B2Publication Date: 2015-02-03
- Inventor: Karan Mehra , Surendra Verma , John R. Dietrick
- Applicant: Microsoft Corporation
- Applicant Address: US WA Redmond
- Assignee: Microsoft Corporation
- Current Assignee: Microsoft Corporation
- Current Assignee Address: US WA Redmond
- Agent John Jardine; Kate Drakos; Micky Minhas
- Main IPC: G11B21/08
- IPC: G11B21/08 ; G11B15/02

Abstract:
Upon receiving a request to allocate a storage region, a storage device may initialize the contents of the storage device to default values (e.g., zero) in order to avoid problems arising from unknown data stored in the locations of the storage region (e.g., upon writing a data set to a location involved in a mirroring relationship, uninitialized data in the corresponding mirror location may result in a mismatch that jeopardizes the written data). However, initializing the storage device may be time-consuming and inefficient. Instead, a usage bitmap may be generated that, for respective location sets of the storage region, indicates whether values exist in the location. A read request may be fulfilled by examining the usage bitmap to determine whether values exist in the specified location, and if not, the default value may be returned without accessing the storage device. Other efficiencies may also be achieved using the usage bitmap.
Public/Granted literature
- US20130265861A1 EFFICIENT ACCESS TO STORAGE DEVICES WITH USAGE BITMAPS Public/Granted day:2013-10-10
Information query
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