Patent ID: 7451192
Filing Date: 2008-11-11
Classification: G06F,H04L,H04N

Abstract:
1. A data communication apparatus for controlling communications of data between a terminal and a data storage unit by way of a network, said data communication apparatus comprising: an acceptance means for accepting a request for a communication through said network from said terminal connected to said network; a communication means for communicating data with said terminal by way of said network; an issuance means for issuing an access command and a control command from an ordered plurality of control commands to said data storage unit in accordance with a request for a communication received by said acceptance means; a memory for temporarily holding the access command issued by said issuance unit, data received from said terminal and data to be transmitted to said terminal; a first controller for controlling said acceptance means, said communication means, said issuance means and said memory; a control-command buffering means for buffering the control command from the ordered plurality of control commands issued by said issuance means; a fetching means for fetching the control command buffered in said control-command buffer, wherein the control command is sequentially judged to be a DMA-command down, then a DMA data down, then a DMA data up, then a RAID command down, then a RAID data down, then a RAID data up; an acquisition means for acquiring the access command held by said holding in accordance with the control command fetched by said fetching means; an output for outputting the access command acquired by said acquisition means to said data storage unit; a data buffer for buffering data to be stored in said data storage unit or data read out from said data storage unit; a transfer means for transferring data between said memory and said data buffer in accordance with the control command fetched by said fetching means; and a second controller for controlling said control-command buffer, said fetching means, said acquisition means, said output means, said data buffer and transfer means, wherein said first and second control means operate independently of each other.