Mangosoft, Inc. v. Oracle Corp.

Mangosoft, Inc. and Mangosoft Corporation (collectively, Mangosoft) (plaintiff) owned a US patent directed to computer networks. The patent disclosed virtual-memory systems shared by computers on a network. Mangosoft’s system leveraged the storage capacity of individual client computers by allowing each computer in the network to contribute portions of its local persistent (hard disk) memory to the virtual memory, thus providing a decentralized data-storage system. Mangosoft sued Oracle Corp. (defendant) for patent infringement in the United States District Court for the District of New Hampshire. Claim 1 of Mangosoft’s patent, one of the claims that Mangosoft asserted against Oracle, recited that “a local persistent memory device” was coupled to each computer. In the claim-construction phase of the case, Mangosoft contended that the term “local” meant that the memory device could “be contributed to the shared addressable memory space by a particular mode.” Oracle, on the other hand, advocated for a narrower interpretation, citing the following definition of “local device” from McGraw-Hill Dictionary of Scientific and Technical Terms: “[p]eripheral equipment that is linked directly to a computer or other supporting equipment without an intervening communications channel.” Although the district court did not cite that dictionary, it sided with Oracle overall, finding that Mangosoft’s proposed definition would render the term “local” superfluous. The court construed “local” as “a computer device (e.g., a hard drive) that is directly attached to a single computer’s processor by, for example, the computer’s bus.” Based on that claim construction, the district court entered a judgment of noninfringement. Mangosoft appealed, faulting the “directly attached” portion of the district court’s interpretation of “local,” contending that the district court, though not expressly citing the McGraw-Hill technical dictionary definition, placed undue reliance upon that definition in reaching its interpretation of “local.”