Abstract: In a method of controlling an information processing system in which an information processing device is connected to each of a plurality of input/output ports provided in a routing device and having a first property or a second property, for conducting data transmission among the information processing devices via the routing device, a step of causing all of the information processing devices to halt data transmission, a step of resetting properties and identification information of the input/output ports with the second properties other than the input/output port with the first property which cannot be used, in the routing device, and a step of causing the information processing devices to restart the data transmission after the reset of the identification information are executed.

Abstract: A DMA apparatus which reads data corresponding to a descriptor from memory, and a dividing unit in a descriptor management device divides one descriptor into a plurality of sub-descriptors. A plurality of DMA controllers produce a plurality of reading requests for reading data corresponding to the plurality of sub-descriptors from the memory. A memory controller reads the corresponding data from the memory according to the plurality of reading requests.

Abstract: A file control system performing DMA (direct memory access) transfer is provided. The file control system includes file control devices, and each of the file control devices is provided between a host computer and an external storage device. A first file control device among the file control devices checks for errors in the data read from a memory, changes the error detection code added to the read data from a first error detection code to a second error detection code, changes at least a part of the data when an error is detected, and executes DMA-transfer of the data, which is changed or is not changed, to a second file control device of the transfer destination.

Abstract: A file control system of the present invention is a file control system performing DMA transfer and comprising a plurality of file control devices, each of which is provided between a host computer and an external storage device, a first file control device among the plurality of file control devices, checks the consistency between the data read from a memory and the first error detection code given in advance to the data, changes the error detection code added to the read data from the first error detection code to a second error detection code, when the inconsistency is detected by the check, changes at least a part of the data comprising the second error detection code and the data associated with the second error detection code, and executes DMA-transfer of the data which is changed or is not changed to a second file control device of the transfer destination.

Abstract: A DMA apparatus which reads data corresponding to a descriptor from memory, and a dividing unit in a descriptor management device divides one descriptor into a plurality of sub-descriptors. A plurality of DMA controllers produce a plurality of reading requests for reading data corresponding to the plurality of sub-descriptors from the memory. A memory controller reads the corresponding data from the memory according to the plurality of reading requests.

Abstract: In a method of controlling an information processing system in which an information processing device is connected to each of a plurality of input/output ports provided in a routing device and having a first property or a second property, for conducting data transmission among the information processing devices via the routing device, a step of causing all of the information processing devices to halt data transmission, a step of resetting properties and identification information of the input/output ports with the second properties other than the input/output port with the first property which cannot be used, in the routing device, and a step of causing the information processing devices to restart the data transmission after the reset of the identification information are executed.