Patent ID: 6209058
Filing Date: 2001-03-27
Classification: G06F

Abstract:
In a cache system comprising a cache buffer including a plurality of data blocks for storing data, and a cache manager for transferring data into and out of the cache buffer, including retrieving data from a disk drive and storing said data into the cache buffer, the disk drive comprising a data disk having a plurality of concentric data tracks thereon, a spindle motor for rotating the data disk, and a transducer supported by a carrier for positioning the transducer over a selected data track to write data thereto or read data therefrom,a method of data transfer in response to a request for retrieving a set of data blocks from the selected track, comprising the steps of:(a) defining a data segment on the selected track, wherein the data segment comprises, in sequence: (1) a pre-fetch data area, (2) a fetch data area comprising said set of data blocks, and (3) a post-fetch data area;(b) determining a landing position of the transducer over the selected track relative to the data segment; and(c) controlling transfer of data from the data segment to the cache buffer based on said landing position, wherein:(1) if said landing position is outside the data segment, delaying reading data from the data segment until the pre-fetch data area rotates under the transducer, thereafter commencing reading data from the pre-fetch area;(2) otherwise, commencing reading data from said landing position in the data segment without delay.