Patent ID: 6349358
Filing Date: 2002-02-19
Classification: G06F

Abstract:
A magnetic disc control system comprising:a magnetic disc drive; a cache memory from which data is read out with a higher priority than from the magnetic disc drive; and a magnetic disc control apparatus comprising: an I/O processor for receiving an I/O request from a host computer, reading out from the cache memory or the magnetic disc drive, data corresponding to the I/O request, and passing the data item to the host computer; a near sequential I/O identifier for deciding, each time an I/O request is entered from the host computer to the I/O processor, whether a current I/O is a near sequential I/O; a pre-read executor for pre-reading data in the magnetic disc drive after a current I/O transfer end address and storing the pre-read data in the cache memory if the current I/O is a near sequential I/O; and an I/O history storage table for storing I/O transfer end addresses of previous requests made from the host computer, wherein the near sequential I/O identifier calculates an address difference between the I/O transfer end address read out from the I/O history storage table and a current I/O transfer start address, and wherein the near sequential I/O identifier identifies the current I/O as a near sequential I/O when the address difference is greater than one but smaller than the current I/O transfer length multiplied by a predetermined number.