Being the scheduling manner which does the scheduling which decides the execution sequence of demand for not yet treatment to

摘要

PROBLEM TO BE SOLVED: To provide a technology for scheduling a request while reducing the frequency of the attachment/detachment of a recording medium in a two-dimensional storage in an HSM(hierarchical storage management) system.;SOLUTION: A hierarchical controller refers to a request executed by each tape driver device 37 loaded on a two-dimensional storage as a history, and the tape driver device 37 in which the predetermined number of read requests for reading data from a cartridge 38 are continued is made exclusive for read request. In the tap driver device 37 exclusive for the read request, its executable request is given priority and executed. Thus, it is possible to perform scheduling by reducing the number of times of the exchange of the cartridge 38. The upper limit number is set for the tape drive device 37 exclusive for the read request so that it is possible to facilitate countermeasures even to any request other than the read request.;COPYRIGHT: (C)2008,JPO&INPIT