It is generally improper to impose requirements on claim terms that are foreign to what the specification describes as the invention’s relevant advance over the prior art. Here, for example, it was found to be improper to require the claimed “virtual” files to be limited to files stored physically elsewhere when the described advance over the prior art was merely the organizational structure that an interface device conveys to a host computer, not where data physically resides. “[A] construction that is unmoored from, rather than aligned with what is described as the invention’s advance [is improper].” This would be a good case to consult and cite in response to a claim interpretation that relies on purely ancillary characteristics of a claim term that are not relevant to the heart of the invention.
Background / Facts: The patents being asserted here are directed to an interface device for transferring data between an input/output data device (e.g., a digital camera) and a host computer. The claims recite configuring the interface device to use native drivers already present on the host computer, such that the host computer sees “virtual files” and a “virtual file system” that it is already familiar with. The district court construed the “virtual files” of the “virtual file system” to be limited to files “not physically stored on the interface device,” whose content is data “originating from the data transmit/receive device.”
Issue(s): Whether the “virtual files” can contain data already existing physically on the claimed interface device prior to being requested by the host computer.
Holding(s): Yes. “[W]hat the patent describes as the advance over prior art is the use of a host-native driver for obtaining access to data even when the data is not actually on a device of the type for which that driver was designed—in the featured example, not actually on a hard drive. Nothing in the written description suggests that this depends on what non-host physical memory units hold the data as long as the interface device mimics the data-organizational tools expected by the host-native driver, such as directory structures for a hard-disk drive, to enable the host to gain access to it. To impose the district court’s requirement tied to physical location is to introduce a meaning of ‘virtual’ that is foreign to what is described as the invention’s advance. An interface device file is ‘virtual’ in the only way relevant to the invention when it organizes data in a manner that allows the host to use its native driver to gain access to the data even if the data is not actually on a device for which the native driver was designed—regardless of where else that data may be.”