US 2009/0157957 A1 · APPARATUS WITH DISC DRIVE THAT USES CACHE MANAGEMENT POLICY TO REDUCE POWER CONSUMPTION

Abstract

Data blocks are loaded in multi-block fetch units from a disc. Cache management policy is selects data blocks for non-retention in cache memory so as to reduce the number of fetch units that must be fetched. Use is made of the large multi-block fetch unit size to profit from the possibility to load additional blocks essentially without additional power consumption when a fetch unit has to be fetched to obtain a block. Selection of data blocks for non-retention is biased toward combinations of data blocks that can be fetched together for a next use in one fetch unit. Between fetching of fetch units the disc drive is switched from a read mode to a power saving mode, wherein at least part of the disc drive is deactivated, so that energy consumption is reduced. Retention is managed at a granularity of data blocks, that is, below the level of the fetch units. If a combination of blocks from the same fetch unit can be fetched together at one go before their next use, these blocks are not retained if as a result other blocks, from a plurality of other fetch units, can be retained in place of the combination of blocks.

Claims11

Dependent claims

An information processing apparatus, comprising:

a disc drive (10) arranged to read data from a disc (100), a fetch unit at a time, each fetch unit containing a plurality of data blocks that are stored substantially contiguously on the disc (100);
a processing circuit (14) for executing a program using the data blocks;
a cache memory (12) coupled to the disc drive for caching data blocks read from the disc (100) for use by the processing circuit (14) during execution of the program, the cache memory (12) having a replacement granularity of individual data blocks;
a cache management unit (16) arranged to select which data blocks from within the fetch units not to retain in the cache memory (12), dependent on a prediction of when which data block will be needed during execution of the program, the cache management unit (16) selecting not to retain at least a first data block in response to information about a cache status and expected time that a second data block in a same fetch unit as the first data block will be needed next, so that space in the cache memory (12) is freed by not retaining the first data block if it is predicted that the first data block will be fetched when the second data block is predicted to be fetched, before the next use of the first data block.

1 more element

Dependencies are inferred from the claim text.

Apparatus with disc drive that uses cache management policy to reduce power consumption

Life of this patent

Apparatus with disc drive that uses cache management policy to reduce power consumption

Life of this patent

Abstract

Claims11