Patent ID: 7716392

Claim:
A computer system comprising: an input/output circuit connectable to a utility device and configured to transfer and receive data to or from the utility device; a main storage configured to store the data received and to transmit data to be transferred; a control circuit connected to said main storage via a bus and configured to read out the received data stored in said main storage and to write the transmission data to said main storage; and at least one direct connecting line configured to directly link said main storage exclusively with said input/output circuit; said input/output circuit being directly connected to said main storage by the direct connecting line and being configured to directly write the received data transferred from the utility device to said main storage and to directly read out the transmission data from said main storage to transfer the transmission data to the utility device to thereby execute DMA (Direct Memory Access) transfer without using bus, said main storage comprising a memory for storing the received data or the transmission data, and an arbitrator for arbitrating a memory access right each having access to said memory without using the bus, said arbitrator switching the memory access right in response to a request signal that requests an allowance of the memory access right, said input/output circuit feeding the request signal to said arbitrator in order to execute DMA transfer, and executing, when the memory access right is allowed, the DMA transfer to said memory.