Patent ID: 7263580

Claim:
A cache control method in a data processing system having a computer, which includes a synchronous point processing section, for executing a program, and a storage unit having a cache memory for storing data transmitted as a result of execution of said program, a cache controller having a cache management table and a disk device having memory medium for storing data stored in said cache memory, wherein said synchronous point processing unit makes and sends a write request of updated data held in the memory medium of data processed by the program in a write-through mode to update data of the program unreflected upon said disk device, issues a flash command to said storage unit in order to reflect the updated data upon the memory medium at a timing synchronous with a commitment to perform a transaction process, and makes and sends a write-request, in the write-through mode, to said storage unit for requesting write of a synchronous point journal which records, in the storage unit, completion of a synchronous point process until a check point from said computer to said storage unit, wherein said cache controller of storage unit, responding to said flash command from said synchronous point processing section, if a mode in said cache management table corresponding to a page for said flash command coincides with write-after, writes the page indicated by a cache pointer for the page in said cache management table to said memory medium and changes a cache management entry in said cache management table to a state of reflected, wherein said cache controller of said storage unit, responding to said write request, if a mode designated during said write request is write-after, writes data in said cache memory, and changes said cache management entry for the page to a state of unreflected, and wherein said cache controller of said storage unit, responding to said write request, if said mode designated during said write request is not write-after, writes the page to both said cache memory and said memory medium, thereafter changes said cache management entry for the page to the state reflected.