| 摘要 |
PROBLEM TO BE SOLVED: To reduce issuance frequency of commands to a coupling device and to reduce data transfer quantity to reduce response time to the commands when a cache of the coupling device is applied in a system to perform multiple write of the same data in plural files. SOLUTION: When the multiple write of the same data in the plural files on DASD is performed, plural directory items corresponding to the plural files are registered in a global cache in the coupling device in block and the same data is shared by the plural directory items. In addition, when a file on the DASD is copied to another plural files on the DASD, the plural directory items corresponding to files at copying destinations are registered on the global cache in the coupling device in block and cache data held by the directory item corresponding to the files at a copying origin is shared by the plural directory items corresponding to the files at the copying destinations. |
