PTAB

IPR2016-01779

SpringPath Inc v. SiMPLiVity Corp

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Computer File System Data Structures
  • Brief Description: The ’799 patent describes a stacked computer file system architecture. It comprises a "namespace file system" layered on top of an underlying "object store," where data objects are named and accessed using content-derived cryptographic hashes, referred to as "fingerprints."

3. Grounds for Unpatentability

Ground I: Anticipation by Li - Claims 1-2, 7-9, 11-12, 17-20, 27, and 33-35 are anticipated by Li under 35 U.S.C. §102.

  • Prior Art Relied Upon: Li et al., "Secure Untrusted Data Repository (SUNDR)," published in 2004.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Li discloses every limitation of the challenged claims. Li’s SUNDR is a content-addressable network file system with a layered architecture identical to that claimed in the ’799 patent. Specifically, Li's client-side software, which manages files and directories, functions as the claimed "namespace file system," while its server-side, hash-indexed "block store" is the claimed "object store." Li teaches naming all on-disk data structures using cryptographic handles (SHA-1 hashes), which are the claimed "fingerprints."
    • Petitioner further mapped Li's data structures to specific claim elements. Li’s "user i-tables," which map inode numbers to inode hashes ("i-hashes"), were identified as the claimed "inode map object." This structure enables inode numbers to remain constant while the content-derived fingerprints change, as required by the claims. Li’s "directory entries," which map file names to inode numbers, were argued to be the claimed "directory objects." Petitioner contended that both the i-tables and directory objects in Li have their own content-derived fingerprints (called "i-handles"), thus meeting the final limitations of independent claims 1 and 19. The dependent claims were argued to add only well-known features also disclosed in Li, such as a root object (the "i-handle"), tree structures for file objects (inodes containing hashes of data blocks), and variable-sized objects.

Ground II: Obviousness over Li in view of Sandberg - Claim 10 is obvious over Li in view of Sandberg under 35 U.S.C. §103.

  • Prior Art Relied Upon: Li (as in Ground I) and Sandberg et al., "Design and implementation of the Sun network filesystem," published in 1985.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that claim 10 adds the limitation that the namespace file system is a layer between a "virtual file system layer" (VFS) and a "block storage abstraction layer." While Li discloses the base system, Sandberg explicitly teaches a VFS interface for the Sun Network File System (NFS) that separates generic filesystem operations from specific implementations. Sandberg’s NFS is provided as a layer between the VFS and the block storage layer.
    • Motivation to Combine: A POSITA would combine Li with Sandberg to gain the known benefits of a VFS, such as operating system independence and transparent access to remote files. Li itself acknowledges its SUNDR system is similar to other network file systems like NFS. Given that both references describe layered network file systems solving the same problem, adding Sandberg's VFS layer to Li's architecture was presented as a simple, predictable design choice to improve interoperability.
    • Expectation of Success: A POSITA would have had a high expectation of success, as combining layered software components was a routine skill.

Ground III: Obviousness over Li - Claim 13 is obvious over Li under 35 U.S.C. §103.

  • Prior Art Relied Upon: Li (as in Ground I) and the Portable Operating System Interface (POSIX®) standard.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that claim 13, which requires the file system to be "POSIX standard compliant," is rendered obvious by Li. Li discloses that for its experiments, the system components communicated over "Unix-domain sockets."
    • Obviousness Rationale: Petitioner asserted that support for Unix-domain sockets is a mandatory component of the POSIX standard. Therefore, a POSITA would have understood that a system built using such standard components, like SUNDR, would be POSIX compliant or would have been motivated to ensure its compliance for standard interoperability. This modification would have been a trivial implementation detail for a POSITA in the field.

4. Key Claim Construction Positions

  • "fingerprint": Petitioner proposed this term be construed as "hash value of an object's content." This construction was argued to be consistent with the specification and necessary to map the claims onto Li's disclosure of using cryptographic handles and SHA-1 hashes to identify and access data blocks.
  • "namespace file system": Petitioner proposed this term be construed as "a file system that accesses data and metadata as objects that are referred to by name." This construction was used to identify the client-side software in Li, which manages file and directory structures by name, as the corresponding claimed element, distinct from the underlying content-addressed object store.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1–2, 7–13, 17–20, 27, and 33-35 of the ’799 patent as unpatentable.