A pre-fetch method for a data storage system having disk drives and a
cache memory. The method generates a history as pages are from the disk
drives for storage in the cache memory, such history indicating whether a
page previous to the requested page is already in the cache memory. The
history generation is used during subsequent requests to determine, when
a page is again requested, the number of pages that are to be read from
the disk drive into the cache memory, the number of pages to be read
being determined from the generated history.