초록 ▼

A data transfer apparatus is provided for transferring data with a DMA method between a plurality of disk apparatuses and a memory using a DMA command table. A processor generates the DMA command table composed of an array of the DMA commands which are each composed of an address (starting address)

A data transfer apparatus is provided for transferring data with a DMA method between a plurality of disk apparatuses and a memory using a DMA command table. A processor generates the DMA command table composed of an array of the DMA commands which are each composed of an address (starting address) of the data area and a size of data to be transferred. A disk access unit transfers data between the disk apparatuses and the memory using the DMA command table. When it is judged that the disk apparatus currently transferring data has temporarily released the bus use right, the processor, concurrently in preparation for the resumption of the data transfer, updates the DMA command table by deleting DMA commands having been executed and adding new DMA commands. This eliminates or reduces the generation of the table update interrupt.

대표청구항 ▼

[ What is claimed is:] [1.] A data transfer apparatus for transferring data with a DMA method between a plurality of disk apparatuses and a memory using a DMA command table, wherein the plurality of disk apparatuses are connected to a bus, wherein each of the plurality of disk apparatuses obtains a

[ What is claimed is:] [1.] A data transfer apparatus for transferring data with a DMA method between a plurality of disk apparatuses and a memory using a DMA command table, wherein the plurality of disk apparatuses are connected to a bus, wherein each of the plurality of disk apparatuses obtains a bus use right for using the bus for a transfer of data, temporarily releases the bus use right depending on an internal state of the disk apparatus, and obtains the bus use right when resuming the transfer of data, the data transfer apparatus comprising:table generating means for generating the DMA command table which includes an array of a plurality of DMA commands, wherein each of the plurality of DMA commands includes an address of a data area of the memory and a size of a piece of data to be transferred;transferring means for performing a data transfer between one of the plurality of disk apparatuses and the memory using the DMA command table;temporary release judging means for judging whether the disk apparatus in the data transfer has temporarily released the bus use right; andtable updating means for, when the temporary release judging means judges that the disk apparatus has temporarily released the bus use right, performing a repair process for preserving a current state in preparation for a reconnection, and updating the DMA command table by deleting DMA commands which have been executed and adding new DMA commands so that the disk apparatus resumes the data transfer.