Patent ID: 7155492

Claim:
A server system comprising a network interface, a secondary storage unit, a connection interface to the secondary storage unit, storage means for storing an OS and a device driver for said secondary storage unit, and a processor which runs said device driver and said OS, wherein, receiving a read request issued from said OS to read data, said device driver determines whether said data resides on said secondary storage unit; if said data does not reside on said secondary storage unit, said device driver requests said network interface to transmit the read request outside of said secondary storage unit; if said data resides on said secondary storage unit, said device driver requests said connection interface to read said data; wherein, receiving a write request issued from said OS to write data, said device driver determines whether said data resides on said secondary storage unit; if said data does not reside on said secondary storage unit, said device driver requests said network interface and said connection interface to transmit the write request to said secondary storage unit so as to write said data thereinto; if said data resides on said secondary storage unit, said device driver requests said network interface to transmit said write request to said connection interface and requests said connection interface to overwrite said data on said secondary storage unit, and wherein said device driver directly operates physical devices to cache data without involving said OS.