Patent ID: 6253289
Filing Date: 2001-06-26
Classification: G06F

Abstract:
Storage controller apparatus for controlling transfers of records in a record storage system between storage devices, a cache and a host computer, said apparatus comprising:initiate module initiating a prefetch of a predetermined number of records from the storage devices for transfer to the cache in order to return requested records to the host computer in response to a read from the host computer;test module, responsive to the read request, detecting if the requested records are in cache and therefore a previous prefetch is complete;prefetch size module, responsive to a detection by said test module that the previous prefetch of data is not complete, increasing the number of records in the next prefetch of records by a preset amount and thereafter enabling said initiate module to initiate a next prefetch of records; andsaid initiate module, responsive to a detection by said detection module that the previous prefetch of data is complete, initiating a next prefetch of records with the number of records in the prefetch being the same as in the previous prefetch;a history module detecting a sequential read stream in a plurality of read requests from the host computer and enabling said initiate module to initiate a prefetch;a detecting module detecting whether the current read request is a cache miss or a prefetch hit;set module responsive to detection of said cache miss by said detecting module for setting the prefetch size to the size of the read request; andsaid test module, responsive to the detection of said prefetch hit by said detecting module, being enabled to detect if the previous prefetch is complete.