Storage management of data for ensuring communication of minimal length data
First Claim
1. In a system including a host, at least one storage subsystem, the storage subsystem including at least one storage media, a compressor coupled between the at least one storage subsystem and the host for compressing data transferred therebetween;
- a system for ensuring the communication of the minimal length data stream to the storage subsystem comprises;
descriptor means coupled to the compressor and the host for providing an indication that the data stream has been compressed;
first buffer means coupled to the descriptor means for receiving an original data stream from the host;
second buffer means coupled to the compressor for receiving a compressed data stream from the compressor;
means coupled to the first and second buffer means for comparing the length of the original data stream to the compressed data stream and swapping data from the first buffer means with data in the second buffer means when the first buffer means data is shorter in length; and
means coupled to the comparing means for providing the shorter length of the data stream and the compressed data stream to the at least one storage media from the second buffer means.
1 Assignment
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Accused Products
Abstract
A method and apparatus for ensuring the communication of a minimal length data stream in a system including a host and a storage management device is provided. The method and apparatus includes first and second buffers for simultaneously receiving compressed data and the original data from the host. The system compares the length of the data in the first and second buffers. If the data has expanded, indicating that compressed data is longer than the original data, the original data is provided to the storage media. If the data has not expanded, indicating that the original data is longer than the compressed data, then the compressed data is provided to the storage media.
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Citations
21 Claims
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1. In a system including a host, at least one storage subsystem, the storage subsystem including at least one storage media, a compressor coupled between the at least one storage subsystem and the host for compressing data transferred therebetween;
- a system for ensuring the communication of the minimal length data stream to the storage subsystem comprises;
descriptor means coupled to the compressor and the host for providing an indication that the data stream has been compressed; first buffer means coupled to the descriptor means for receiving an original data stream from the host; second buffer means coupled to the compressor for receiving a compressed data stream from the compressor; means coupled to the first and second buffer means for comparing the length of the original data stream to the compressed data stream and swapping data from the first buffer means with data in the second buffer means when the first buffer means data is shorter in length; and means coupled to the comparing means for providing the shorter length of the data stream and the compressed data stream to the at least one storage media from the second buffer means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
- a system for ensuring the communication of the minimal length data stream to the storage subsystem comprises;
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14. In a system including a host, at least one storage subsystem, the storage subsystem including at least one storage media, a compressor coupled between the at least one storage subsystem and the host for compressing data transferred therebetween;
- a method for ensuring the communication of the minimal length data stream to the storage subsystem comprises the steps at the subsystem of;
(a) providing an indication that the data stream has been compressed; (b) receiving an original data stream from the host in a first buffer means; (c) receiving a compressed data stream from the compressor in a second buffer means; (d) comparing the length of the original data stream to the compressed data stream and swapping data from the first buffer means with data in the second buffer means when the first buffer means data is shorter in length; and (e) providing the shorter length of the data stream and the compressed data stream to the at least one storage media from the second buffer means. - View Dependent Claims (15, 16, 17, 18)
- a method for ensuring the communication of the minimal length data stream to the storage subsystem comprises the steps at the subsystem of;
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19. In a system including a host accessing byte strings of at least one record in length resident among at least one of a plurality of attached peer-coupled storage subsystems, a method for managing minimal length byte string communication on the fly within a data patch between the host and a storage medium portion of the subsystem and among peer coupled subsystems, comprising the steps at the subsystem of:
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(a) responsive to a write access from the host, ascertaining whether the access is an update of a previously recorded byte string, if not, concurrently applying the byte string to a compressor and to a buffer; (b) responsive to a write access not updating a byte string recorded in the subsystem comparing the length of the first record of the byte string under compression with the original record stored in the buffer and selecting the minimal length one of the two strings based on the minimal length of the first record, appending a descriptor indicative of the compression status to the selected string, and either recording the selected string and the descriptor in a storage medium or communicating the same to a peer coupled subsystem; and (c) responsive to a write access updating a byte string recorded in the subsystem, concurrently applying the byte string to the compressor and the buffer, selecting the minimal length string from the compressor or the buffer according to the descriptor of the byte string being updated. - View Dependent Claims (20)
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21. A computer readable medium containing program instructions for ensuring the communication of a minimal length data stream between a host and at least one storage subsystem, the program instructions comprising:
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providing an indication by a descriptor that the data stream has been compressed by a compressor, the compressor coupled between the host and the at least one storage subsystem; receiving the data stream in a first buffer, the first buffer coupled to the descriptor; receiving the compressed data stream from the compressor in a second buffer; comparing the length of the data stream in the first buffer to the compressed data stream in the second buffer and swapping the data stream from the first buffer with data in the second buffer when the first buffer data stream is shorter in length; and (e) providing the shorter length of the data stream and the compressed data stream to the at least one storage subsystem from the second buffer means.
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Specification