Wednesday, April 12, 2023

Sequoia v. Dell: mixed decision

The outcome:

Sequoia Technology, LLC appeals from a stipulated judgment of noninfringement and invalidity of U.S. Patent No. 6,718,436 following an adverse claim construction ruling from the United States District Court for the District of Delaware. For the reasons below, we disagree with the district court’s claim construction for “computer-readable recording medium,” and thus we reverse the district court’s ineligibility determination under 35 U.S.C. § 101. In addition, we agree with the district court’s claim construction for “disk partition” and “logical volume,” and thus we affirm the district court’s noninfringement determination.

Factual details

The technology at issue is digital storage. The ’436 patent explains that servers with important data can use “Redundant Array of Independent Disks” (RAID) to store the same data on multiple hard disks. See ’436 patent col. 1 ll. 26–32. The specification further notes how a virtual disk drive—also known as a logical volume—can encompass multiple physical disk drives. Id. at col. 1 ll. 24–28. A logical volume manager can implement the RAID technique with software to construct a logical volume. Id. The specification teaches that these advances were known, but “conventional logical volume managers ha[d] problems in that metadata is too large to manage in huge storage


In its preliminary response to Red Hat’s IPR petition, ETRI distinguished two prior art references, Bridge and Williams, by highlighting that instead of disk partitions, “extents in Bridge or physical partitions in Williams, both subsets of disk drives[,] . . . are gathered to form a logical volume.” J.A. 1027 (quoting D.I. 178, Ex. K, at 2); see J.A. 936 (similarly explaining that “the extents of Bridge or the physical partitions of Williams,” not disk partitions, are gathered to form the logical volume). Separately, ETRI stated that “[w]hile the logical volume [in the ’436 patent] is formed from extents, extents are added or removed from the logical volume at the level of the disk partitions.” J.A. 921 (emphasis added). These statements are consistent with the understanding that a logical volume in the present invention is only constructed at the level of disk partitions, not sub-portions of disk partitions. Sequoia disagrees. It argues that the distinction ETRI drew between the prior art and the claimed invention was that Bridges and Williams lack any disk partitions (a necessary component of the claim). Appellant’s Br. 38–40. We disagree. ETRI’s statements during prosecution distinguish the prior art based on what element is removed or added to form the logical volume—either disk partitions or subparts of disk partitions. Sequoia argues that ETRI’s second statement above is consistent with “permit[ting] extents to be individually allocated (or not) to the logical volume.” Id. at 38. But ETRI’s reference to removing or adding extents “at the level of the disk partitions” is clear. See J.A. 921. It does not reasonably support a construction that would allow extents—which are sub-portions of disk partitions—to build logical volumes. Finally, Sequoia argues that another limitation in claim 1, directed to an “extent allocation table for indicating whether each extent in the disk is used or not used,” supports its construction of disk partition and logical volume. Appellant’s Br. 27–29. According to Sequoia, “used or not used” in the extent allocation table means used or not used for constructing the logical volume. Accordingly, if Sequoia is correct, then extents—not partitions—are the minimum unit forming the logical volume, and the district court’s construction of “disk partition” and “logical volume” are incorrect. Red Hat, on the other hand, contends that “used or not used” means used or not used for storage. As such, under Red Hat’s construction, this claim language does not undermine the district court’s construction of “disk partition” and “logical volume.” The claim language read in isolation does not clearly support either parties’ construction. Rather, the plain language of the claim limitation “used or not used” begs the question—used for what? Here, in light of the intrinsic evidence that logical volumes are constructed from entire disk partitions, the extent allocation table must point to whether extents are used or not used for storage.


This suggests that “used” does not mean used in the logical volume; rather, it means used for storage. Were it otherwise, the extent allocation table in the preferred embodiment would be superfluous.6 While not dispositive, we find it unlikely that an inventor would define an invention such that an element of a preferred embodiment is superfluous. Cf. Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1583 (Fed. Cir. 1996) (explaining that interpreting a claim such that a preferred embodiment is excluded is “rarely, if ever, correct” because it is unlikely an inventor would define the invention in such a way).


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