A statement during prosecution disclaiming a set of features in concert does not establish disclaimer of any one of those features in isolation. Here, for example, the patentee’s statement during prosecution that the claimed invention does not require a central controller to (1) receive requests from clients and (2) issue requests to data storage units was found to be insufficient to disclaim the use of a central controller to (1) receive requests from clients altogether. It may therefore be helpful to temper potentially disclaiming statements with additional features of the prior art not in contention.
Background / Facts: The patents being asserted here are directed to data storage systems that allow users to store and retrieve large files such as movies. The claims recite a “distributed data storage system” in which data is stored in segments across “a plurality of independent storage units.” During prosecution, the patentee stated that in the claimed invention, in contrast to the prior art, “[c]lients do not issue requests to a central controller that in turn identifies storage units that store the data and issues requests to storage units.”
Issue(s): Whether the patentee’s statements during prosecution disclaimed a system in which the central controller tells the client which storage unit the client should deal with during read and write operations.
Holding(s): No. “What that portion says, by its terms, is that a central controller is excluded if it performs both of two functions: it ‘identifies storage units that store the data and issues requests to storage units.’ [] The language on its face does not exclude a central controller that performs only one or the other of the two stated functions—which would have been the meaning if the phrase had used ‘or’ rather than ‘and.’ In any event, it does not do so clearly, as would be required to find a disclaimer of a central controller that merely identifies the storage units.”