Patent ID: 7362527
Filing Date: 2008-04-22
Classification: G06F,G11B

Abstract:
1. A method of retrieving possibly fragmented data requested by a host from a first memory divided into allocation units, and for supplying said retrieved data as a data stream, characterized in that the method comprises the steps of: preliminary to retrieving the requested data, determining in which allocation units of the first memory the requested data is stored; searching a list of references to defective allocation units of the first memory to determine whether the list contains a reference to at least one of the allocation units determined in the preceding step; when a reference to at least one allocation unit determined in the determining step is contained in the list, storing, as a first part of the requested data, the data stored in the at least one allocation unit in a second memory; and retrieving the requested data by retrieving the first part of the requested data from the second memory and retrieving a second part of the requested data from the first memory, the second part of the requested data being complementary to the first part of the requested data, and supplying the first and second parts as a data stream, wherein the first memory has a nominal data retrieval rate and the list is built up by using a method comprising the steps of: monitoring an average retrieval rate with which data is retrieved from the first memory; determining whether the average retrieval rate drops below the nominal data retrieval rate; when the average retrieval rate drops below the nominal data retrieval rate, determining a part of the data of which retrieval causes the drop of the average retrieval rate; and adding to the list a reference to the allocation units in which data is stored of which the retrieval causes the drop of the average retrieval rate.