| 摘要 |
PURPOSE:To improve the availability of a direct access storage device (DASD) at the time of the occurrence of a fixed access fault by stopping the function of a duplex DASD only for a fault occurring part at the time of occurring a partial fault in the DASD and operating the stopped part as one DASD. CONSTITUTION:Both central processing units(CPUs) 101-1, 101-2 share a pair of magnetic disk processors 110-1, 110-2 to be a kind of DASDs. When a data set in one DASD out of plural pairs of duplex data sets included in a duplex pair of DASDs occurs a fault whose recovery may be impossible, the information is stored. In the case of accessing the duplex DASD in which a fault occurs in one of the data sets, the data sets in the unfailed DASD out of the duplex pair of DASDs are accessed. When there is no fault in the data sets of the duplex DASD, optional data sets can be accessed in the whole duplex DASD. Consequently, the availability of the duplex DASD can be improved even at the time of occurring a fixed access fault. |
