Patent ID: 8289984
Filing Date: 2012-10-16
Classification: G06F

Abstract:
1. A method for efficiently accessing data stored on data-storage devices by an intermediate device linked to the data-storage devices, such as a storage-shelf router, a PCI2/SAS I/O controller, or storage bridge, on behalf of an external controller of host computer, the method comprising: determining a size and a structure of an allocation unit, each allocation unit including a fixed number of two or more consecutive logical blocks and one usable additional data-containing pad region, each allocation unit mapped to, and exactly aligned with, a corresponding fixed number of consecutive device blocks, and each allocation unit containing a fixed amount of non-pad data equal to the fixed number of logical blocks multiplied by the size of each logical block in data-storage units; receiving, from the external controller or host computer, an access request specifying an amount of data equal to the fixed amount of non-pad data in each allocation unit, or to an amount of data equal to an exact multiple of the fixed amount of non-pad data in each allocation unit, the amount of data corresponding to data-storage units within device blocks of the data-storage devices; and carrying out the received access request by accessing a number of consecutive device blocks stored within the data-storage devices that contain the specified amount of data.