Abstract: A disk storage system has a control unit having a plurality of external ports connectable to a mirrored disk including two disks to which write data is written. When the control unit receives two read requests issued from a processor to the disk unit group, a first read operation is performed to read data requested by the first read request from one of the disks and a second read operation is performed to read data requested by the second read request from the other one of the disks. Also, a first transferring operation is performed to transfer data read by the first read operation to one external port of the control unit and a second transferring operation is performed to transfer data read by the second read operation to another external port of the control unit. Further, the data read by the two read operations is transferred to the processor via the external ports.

Abstract: A first host computer writes data as an object of transfer and its location information to a storage subsystem. A second host computer reads out the data as an object of transfer which has been written to said storage subsystem on the basis of the location information thus written thereto. As a result, the data transfer between the host computers can be carried out employing the storage subsystem.

Abstract: A disk conforms to a fixed length format and a storage subsystem shapes a CKD format record from a host computer in a fixed length unit to store shaped data therein. A format conversion program reads a fixed length block from the disk and extracts the shaped CKD format data to obtain such information to access a file system as file management information to thereby access the file system. Moreover, in an operation to write data on the disk, the data which the storage subsystem has received from the host computer is shaped in the conversion program into a sequence of data in a format to be written on the disk and then the sequence of data is written in a fixed length format thereon. Resultantly, data can be shared between systems using mutually different data formats to store data in storages.

Abstract: A sorting system includes a plurality of input nodes, each of which sorts sorting target data distributed and stored in input local disks. An internally sorted result is stored as a plurality of sorted strings in a shared disk connected between the input node and output node. Upon reception of a merge instruction from all input nodes, the output node reads the sorted string from the shared disk and merges it and outputs a whole sorted result of all input data to an output local disk. In a process of obtaining a whole sorted result of all input data through parallel processing by a computer system constituted of a plurality of computers (nodes), a time to sorting input data can be shortened.

Abstract: A sorting system includes a plurality of input nodes, each of which sorts sorting target data distributed and stored in input local disks. An internally sorted result is stored as a plurality of sorted strings in a shared disk connected between the input node and output node. Upon reception of a merge instruction from all input nodes, the output node reads the sorted string from the shared disk and merges it and outputs a whole sorted result of all input data to an output local disk. In a process of obtaining a whole sorted result of all input data through parallel processing by a computer system constituted of a plurality of computers (nodes), a time to sorting input data can be shortened.

Abstract: In response to requests for I/O processing sent from a computer, I/O which should be processed at a priority is enabled to be processed without being affected by other processing, by classifying I/O into those to be processed at a priority and those not to be processed at a priority. The storage control apparatus comprises an I/O processing controller with a memory that is common for the whole controller. The storage control apparatus manages information for dividing and controlling a plurality of I/O processes as priority and non-priority in that memory and operates while suppressing non-priority I/O processing on the basis of information in the memory.

Abstract: A storage system stores multiple copies of data on physical storage implemented, for example, with multiple disk units. Input/output read requests are received from host systems and distributed in a manner that allows parallel read operations to be conducted over the multiple disk units of the physical storage.

Abstract: In allocating an area of a cache memory to each storage unit, proper allocation of the cache memory is made to each storage unit. If the amount of write-after data becomes equal to or more than a threshold value, an allocation limit is set to each disk unit. If CPU issues a data write request requiring the amount of data equal to or more than the allocation limit, the data write request is held in a wait state until the amount of write-after data becomes less than the allocation limit. Therefore, the allocation amount to the disk unit becomes neither too large nor too small. In this manner, proper allocation of the cache memory to each disk unit can be realized.

Abstract: A disk storage system has a control unit having a plurality of external connection points. When the control unit receives two read requests issued from a processor to two disks of a disk unit group, a first read operation is performed to read data requested by the first read request from one of the disks and a second read operation is performed to read data requested by the second read request from the other one of the disks. Also, a first output operation is performed to output data read by the first read operation from one of the external connection points of the control unit and a second output operation is performed to output data read by the second read operation from another of the external connection points of the control unit. The second output operation is started before the first output operation has finished.

Abstract: A heating device comprises an endless rotary member having a peripheral surface to be moved rotatively, a resistance heating member arranged at the peripheral surface of the rotary member and generating a heat when supplied with an electric current, a current receiver member arranged in a space inside the rotary member and electrically connected to the resistance heating member, and a current supply member being in contact with the current receiver member and to be electrically connected to a power source.A heating rotary member for the heating device comprising the endless rotary member, the resistance heating member, and the current receiver member.

Abstract: In a fixing device with a fixing roller that fixes the toner held on a sheet, a pressuring roller that contacts with the fixing roller, and a supply roller that applies the oil to the fixing roller, image noises and offset phenomenon are prevented by replenishing the consumed oil immediately to the supply roller only when the fixing roller is rotating, based on the oil replenishing speed determined by the rotational speed of the fixing roller and the oil replenishing amount determined by the total rotation time of the fixing roller.

Abstract: For a write request from the CPU, the control unit selects a specific disk unit in the disk unit group for the immediate writing of data. In a second kind of load distribution a disk unit is selected to execute read and staging other than the above-mentioned specific disk.

Abstract: The control unit arbitrarily selects a disk unit among the disk units that are inactive when the control unit receives an input/output request involving either read or staging. For a write request, the control unit selects a master disk unit in the disk unit group for the immediate writing of data, and a disk unit other than the above-mentioned master disk is preferably selected to execute the read and staging unit. After writing is used to write the data into the other disk units after the write request execution is completed by writing to the master disk unit.

Abstract: In allocating an area of a cache memory to each storage unit, proper allocation of the cache memory is made to each storage unit. If the amount of write-after data becomes equal to or more than a threshold value, an allocation limit is set to each disk unit. If CPU issues a data write request requiring the amount of data equal to or more than the allocation limit, the data write request is held in a wait state until the amount of write-after data becomes less than the allocation limit. Therefore, the allocation amount to the disk unit becomes neither too large nor too small. In this manner, proper allocation of the cache memory to each disk unit can be realized.

Abstract: A storage controller for controlling a storage device storing a plurality of data records and a dump process executed by using this storage device, the storage controller, before a dump process, setting data records to be dumped in a generation fixed status in response to a request from the processor, and when an update request is made on a data record set in a generation fixed status, stores a before-update data record as a generation fixed data record in an unused area of the storage device or in a cache memory or the like before starting an update process, and when receiving a data record read request for the dump process from the processor, examining the presence of a stored generation fixed data record corresponding to the data record specified by the request, and if there is the corresponding generation fixed data record, transferring the data record to the processor in reply to the read request.

Abstract: In allocating an area of a cache memory to each storage unit, proper allocation of the cache memory is made to each storage unit. If the amount of write-after data becomes equal to or more than a threshold value, an allocation limit is set to each disk unit. If CPU issues a data write request requiring the amount of data equal to or more than the allocation limit, the data write request is held in a wait state until the amount of write-after data becomes less than the allocation limit. Therefore, the allocation amount to the disk unit becomes neither too large nor too small. In this manner, proper allocation of the cache memory to each disk unit can be realized.

Abstract: A disc controller, which is connected to a plurality of channels for supplying access requests and discs. The controller includes a plurality of storage paths which control transfer of data between a cache, the channels and the discs, and a control memory which controls the respective operations of the plurality of storage paths. The control memory stores information which is used to select a storage path in accordance with predetermined standards for storage path selection. A disc or the cache is accessed using the selected storage path.

Abstract: In allocating an area of a cache memory to each storage unit, proper allocation of the cache memory is made to each storage unit. If the amount of write-after data becomes equal to or more than a threshold value, an allocation limit is set to each disk unit. If CPU issues a data write request requiring the amount of data equal to or more than the allocation limit, the data write request is held in a wait state until the amount of write-after data becomes less than the allocation limit. Therefore, the allocation amount to the disk unit becomes neither too large nor too small. In this manner, proper allocation of the cache memory to each disk unit can be realized.

Abstract: An input/output control apparatus connected to a plurality of input/output units such as disc systems and an input/output control method. A cache memory is divided into a plurality of storage areas for data management. Data stored in the disc systems are stored in the storage areas. In response to an output request from a HOST system to the disc systems, data outputted from the latter are stored in the storage areas of the cache memory. The data stored in the storage areas and outputted therefrom in response to the output request are transferred to the disc systems. The storage areas storing the data requested and not yet stored in the disc systems are grouped correspondingly to the disc systems where the output data are to be stored. The resulting group is managed as a first attribute group. Write-after processing for every disc units can be executed in parallel efficiently without involving high processing overhead.

Abstract: In a control unit having a external storage device, a method for selecting a loading method of data stored in the cache memory into the cache memory in accordance with an access pattern to the data, and an apparatus therefor are disclosed. The selection of the loading method is selection of control mode or procedure in accordance with the loading method, and it is attained by a learn function.