Patent ID: 6505273
Filing Date: 2003-01-07
Classification: G06F

Abstract:
A disk control device coupled to a first host device, a second host device, and a disk unit, said disk control device comprising:a first channel adapter coupled between the first host device and the disk unit, said first channel adapter receiving a variable-block access (CKD) command from the first host device and returning processing results to the first host device; a second channel adapter coupled between the second host device and the disk unit, said second channel adapter receiving a fixed-block access (FBA) command from the second host device and returning processing results to the second host device, said second channel adapter comprising an address conversion unit converting fixed-block position address LBA received from the second host device into variable-block position address CCHH; a device adapter coupled to the disk unit and executing an access command from one of the first host device and the second host device to the disk unit in FBA blocks; a cache memory coupled to the device adapter, to the first channel adapter, and to the second channel adapter, said cache memory developing and storing track data as cache blocks in a format that divides a single CKD block into several FBA blocks; a cache function engine coupled to the cache memory and controlling the cache memory; and a resources manager coupled to the cache function engine, to the cache memory, to the first channel adapter, and to the second channel adapter, and managing general resources and controlling processing operations, said resources manager comprising: a first controller calculating an FBA block number of the disk corresponding to variable-block position address CCHH received from the first host device, reading from the disk unit a CKD block including the FBA block indicated by said FBA block number, developing and storing the block in the cache memory, and searching the cache memory for a record specified by the first host device, and a second controller calculating an FBA block number of the disk corresponding to variable-block position address CCHH received from the second host device, reading from the disk unit a CKD block containing the FBA block indicated by the FBA block number, developing and storing the block in the cache memory, and searching the cache memory for a record specified by the second host device.