Data providing device, file server device, and data transfer control method

A file service device comprising:

• a storage device for storing data;
• a plurality of prefetch fill means for prefetching data from said storage device;
• a plurality of buffer means for storing the respectively prefetched data;
• a plurality of transmitting means for transmitting the data stored in said buffer means to terminals;
• a request accepting means for accepting a data read request, sent by a terminal, for reading data from said storage device;
• prefetch judging means for judging, based on data requested by an immediately preceding data read request or on an index pointing to said data, whether data requested by said accepted data read request is already prefetched and stored in one of said buffer means;
• and
• request output means for, when it is judged that the requested data is not yet prefetched, outputting a prefetch request to one of said prefetch fill means and a transmit request to one of said transmitting means, both of said one means corresponding to the terminal issuing said data read request, and for, when it is judged that the requested data is already prefetched, outputting a transmit request to one of said transmitting means, said one means corresponding to the terminal issuing said data read request.

A data providing device comprising:

• request input means for receiving data request commands which are sent over to a network from a plurality of data request means of a plurality of data request devices, said data request commands sequentially requesting a part of a stream data, said part having a size;
• request-command storing means for storing the data request commands received from said request input means into a plurality of groups, the number of said groups varies responsive to the respective data request device;
• control means for transferring, within a predetermined period responsive to the size of the part of the stream data and a transfer rate of data transmitting means, a certain number of data request commands from the data request means to data generating means via said request-command storing means;
• data generating means for generating data in accordance with said data request commands;
• and
• data transmitting means having a transfer rate for transmitting the data generated by said data generaling means to said data request devices over said network.

A file service device comprising:

• a storage device for storing data;
• a plurality of prefetch fill means for prefetching data from said storage device;
• a plurality of buffer means for storing the respectively prefetched data;
• a plurality of terminals for sending a plurality of data read requests,
• a plurality of transmitting means for transmitting the data stored in said buffer means to said plurality of terminals;
• request accepting means for accepting one of said plurality of data read requests, sent by one of said plurality of terminals, for reading data from said storage device and storing said data in one of said plurality of buffer means;
• prefetch judging means for determining if said one buffer means is full;
• and
• request output means for, (1) when it is determined that said one buffer means is full, providing a transmit request to one of said plurality of transmitting means, said one transmitting means corresponding to the terminal issuing said data read request, and (2) when it is determined that said one buffer means is not full, providing a prefetch request to one of said prefetch fill means and a transmit request to said one transmitting means, said one prefetch fill means and said one transmitting means corresponding to the terminal issuing said data mad request.