Abstract: A system for adaptively managing predictive buffer memory prefetching operations to optimize buffer memory hits in a data storage system. The arriving data access request (DAR) stream is monitored for a particular data access pattern and, when a sequential access pattern (SAP) is detected, the buffer memory prefetching storage rule is switched to a circular overwrite mode (COM) to achieve the best sequential access performance. When the sequential access pattern disappears, a nonsequential access pattern (NAP) is detected and the buffer memory prefetching storage rule is responsively switched to a non-sequential or block overwrite mode (BOM) to maximize data block "re-use" hits in the data buffer. Sequential access pattern detection is achieved using a threshold that may be adapted to the size of incoming DARs.