Twin Peaks Software v. IBM Corporation
690 F. App'x 656
| Fed. Cir. | 2017Background
- Twin Peaks owns U.S. Patent No. 7,418,439, directed to a "mirror file system" (MFS) that links and mirrors two file systems via a virtual file system mounted at a single root directory.
- Twin Peaks sued IBM for patent infringement based on IBM products using Panache/Active File Management; the district court construed disputed claim terms and found claims 1 and 4 indefinite under 35 U.S.C. § 112 ¶ 6 (means-plus-function).
- Claim 1 contains a "means for mounting" limitation; claim 4 contains a "mechanism for managing" limitation; both were treated as means-plus-function terms requiring corresponding structure in the specification.
- The district court held the specification failed to disclose adequate corresponding structure: the MFS mount protocol passages describe outcomes (what the mount achieves) but not the algorithm/structure for mounting; the specification discloses code for only one operation (mfs_open) but not the set of operations encompassed by the managing function.
- Twin Peaks argued the spec discloses sufficient structure (data structures like mfs_vfs and mnode and a two-step algorithm for each limitation) and that a person skilled in the art could implement missing details; the court rejected that reliance on general skill to fill disclosure gaps.
- The Federal Circuit affirmed, holding both means-plus-function limitations indefinite because the specification does not clearly link corresponding structure to the claimed functions.
Issues
| Issue | Plaintiff's Argument (Twin Peaks) | Defendant's Argument (IBM) | Held |
|---|---|---|---|
| Whether the "means for mounting" (claim 1) supplies corresponding structure under § 112 ¶ 6 | Spec discloses mfsvfs and describes "setting up" mfsvfs and "inheriting" contents — a two-step algorithm; some structure suffices and skilled artisans can implement missing details | Spec only states the result of MFS mounting and does not disclose an algorithm or structure; patentee cannot rely on ordinary skill to supply structure | Indefinite — no corresponding structure disclosed; affirmed |
| Whether the "mechanism for managing" (claim 4) supplies corresponding structure under § 112 ¶ 6 | Spec shows mnode interception and provides mfs_open code; other operations "follow same procedure" so full managing mechanism is disclosed or can be derived by skilled artisans | Only mfs_open is disclosed; full set of operations in the managing function not disclosed; expert code attempts show gaps; reliance on skill is insufficient | Indefinite — corresponding structure for full managing function not disclosed; affirmed |
| Standard of review for indefiniteness and subsidiary fact findings | N/A — Twin Peaks invoked de novo review for indefiniteness and disputed factual claims about skilled artisan knowledge | District court applied § 112 ¶ 6 analysis; factual findings based on extrinsic evidence reviewed for clear error | Court applied de novo review to indefiniteness; factual findings reviewed for clear error; affirmed district court conclusions |
Key Cases Cited
- Biomedino, LLC v. Waters Techs. Corp., 490 F.3d 946 (Fed. Cir. 2007) (absence of corresponding structure in specification renders means-plus-function claim indefinite)
- Atmel Corp. v. Information Storage Devices, Inc., 198 F.3d 1374 (Fed. Cir. 1999) (some structure in the specification can satisfy § 112 ¶ 6, but it must correspond to the claimed means)
- Cardiac Pacemakers, Inc. v. St. Jude Medical, Inc., 296 F.3d 1106 (Fed. Cir. 2002) (corresponding structure need not include every enabling detail; enablement is separate inquiry)
- Robert Bosch, LLC v. Snap-On Inc., 769 F.3d 1094 (Fed. Cir. 2014) (court must identify structure in the specification corresponding to asserted functions for means-plus-function claim construction)
- Teva Pharmaceuticals USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831 (U.S. 2015) (review standards: subsidiary factual findings based on extrinsic evidence are reviewed for clear error)