Patent ID: 7689807

Claim:
A mass storage device comprising: a host interface, for interfacing to a host device; a memory module, operably coupled to the host interface; and a mass storage controller, operably coupled to the host interface and the memory module, for writing blocks of host data to the memory module in response to write commands from the host device and for retrieving blocks of stored data for transmission to the host device in response to read commands from the host device, the mass storage controller including: a packet filter module for receiving a packet containing an updated sector of a remote file allocation table from the host device, the updated sector having updated sector contents, the packet filter module further operable for scanning the updated sector contents to determine a state of the updated sector contents, for writing the updated sector to a local file allocation table stored in the memory module when the state of the updated sector contents matches a non-empty state, and for retaining an original sector of the local file allocation table corresponding to the updated sector when the state of the updated sector contents matches an empty state, the non-empty state indicating that a portion of user data corresponding to the updated sector contents is currently in use, and the empty state indicating that the portion of user data corresponding to the updated sector contents is not currently in use.