Abstract: A storage system includes a storage and control units. In each of the control units: a relay unit relays access to the storage; an access controller accesses the storage through one of the relay unit in the control unit and the relay unit in another of the control units; and an operational-state controller determines whether or not the relay unit in the above-mentioned another control unit is usable when the operational-state controller detects occurrence of an abnormality in the above-mentioned another control unit, and makes the above-mentioned another control unit transition to a partially-operational state when the relay unit in the above-mentioned another control unit is usable. In the partially-operational state, at least the access controller in the above-mentioned another control unit is not in operation and the access controller in the control unit can access the storage through the relay unit in the above-mentioned another control unit.

Abstract: A storage system includes a storage and control units. In each of the control units: a relay unit relays access to the storage; an access controller accesses the storage through one of the relay unit in the control unit and the relay unit in another of the control units; and an operational-state controller determines whether or not the relay unit in the above-mentioned another control unit is usable when the operational-state controller detects occurrence of an abnormality in the above-mentioned another control unit, and makes the above-mentioned another control unit transition to a partially-operational state when the relay unit in the above-mentioned another control unit is usable. In the partially-operational state, at least the access controller in the above-mentioned another control unit is not in operation and the access controller in the control unit can access the storage through the relay unit in the above-mentioned another control unit.

Abstract: A power supply unit supplies power for each of a plurality of power supply groups configured to supply the power to a first recording device that belongs to a first redundant-array-of-independent-disks group and a second recording device that belongs to a second redundant-array-of-independent-disks group. The second redundant-array-of-independent-disks group includes recording devices different from those of the first redundant-array-of-independent-disks group. A power-supply control unit cuts off, when a malfunctioning occurs in a specific recording device, power supply to a power supply group that includes the specific recording device.

Abstract: On the basis of a period of a timing signal, a signal propagation delay in a device unit, signal propagation delay in the timing signal bus and the data bus, and a setup time of another device unit or a device connected to the data bus, a timing at which noise caused by active connection of the first device to the data bus is propagated to the other device unit or the device is computed in a step of noise propagation computing, and on the basis of the timing computed in the step of noise propagation computing, a connection timing at which the first device unit is connected to the data bus. With thes two steps, a noise caused by active connection of a device unit does not affect other device units and devices connected to the same data bus.

Abstract: A design method for a bus system comprising a noise propagation computation step and a connection timing computation step. Based on the cycle of a timing signal, a signal propagation delay in a device unit, signal propagation delays in a timing-signal bus and a data bus, and a setup time in the device unit or device connected on the data bus, the noise propagation computation step computes timing at which, when the device unit is connected on the data bus being active, noise propagates to other device units other than the connected device unit or to the device connected on the data bus. Based on the timing computed in the noise propagation computation step, the connection timing computation step computes connection timing at which the device unit is connected on the data bus.

Abstract: A power supply unit supplies power for each of a plurality of power supply groups configured to supply the power to a first recording device that belongs to a first redundant-array-of-independent-disks group and a second recording device that belongs to a second redundant-array-of-independent-disks group. The second redundant-array-of-independent-disks group includes recording devices different from those of the first redundant-array-of-independent-disks group. A power-supply control unit cuts off, when a malfunctioning occurs in a specific recording device, power supply to a power supply group that includes the specific recording device.

Abstract: On the basis of a period of a timing signal, a signal propagation delay in a device unit, signal propagation delay in the timing signal bus and the data bus, and a setup time of another device unit or a device connected to the data bus, a timing at which noise caused by active connection of the first device to the data bus is propagated to the other device unit or the device is computed in a step of noise propagation computing, and on the basis of the timing computed in the step of noise propagation computing, a connection timing at which the first device unit is connected to the data bus. With thes two steps, a noise caused by active connection of a device unit does not affect other device units and devices connected to the same data bus.

Abstract: A design method for a bus system comprising a noise propagation computation step and a connection timing computation step. Based on the cycle of a timing signal, a signal propagation delay in a device unit, signal propagation delays in a timing-signal bus and a data bus, and a setup time in the device unit or device connected on the data bus, the noise propagation computation step computes timing at which, when the device unit is connected on the data bus being active, noise propagates to other device units other than the connected device unit or to the device connected on the data bus. Based on the timing computed in the noise propagation computation step, the connection timing computation step computes connection timing at which the device unit is connected on the data bus.