PTAB

IPR2023-01373

BMW of North America, LLC v. Foras Technologies Ltd.

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1. Case Identification

2. Patent Overview

  • Title: System and Method for Detecting and Recovering from Loss of Lockstep in Processors
  • Brief Description: The ’958 patent discloses a system with a pair of lockstep processors (master and slave) that uses firmware to detect a "loss of lockstep" (LOL). The firmware determines if the detected LOL is recoverable and, if so, cooperates with the operating system, potentially using Advanced Configuration and Power Interface (ACPI) methods, to recover lockstep and reintroduce the processors to the system.

3. Grounds for Unpatentability

Ground 1: Obviousness over Bigbee and Nguyen - Claims 1-8 and 13-22 are obvious over Bigbee in view of Nguyen.

  • Prior Art Relied Upon: Bigbee (Application # 2003/0126498) and Nguyen (Application # 2004/0123201).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Bigbee discloses a data processing system with all the core components of the challenged claims, including a pair of processors operating in lockstep (termed functional redundancy check or "FRC mode"), firmware, and an ACPI-compatible operating system. Bigbee’s firmware detects a loss of lockstep (e.g., an FRC mismatch error or an error within a single processor core) and initiates a recovery routine. However, Petitioner argued Bigbee fails to teach the specific step of determining if the detected loss of lockstep is recoverable. Petitioner contended that Nguyen supplies this missing element. Nguyen discloses a high-reliability processor system that explicitly distinguishes between recoverable errors (e.g., a soft error detected before a mismatch) and non-recoverable errors (e.g., a mismatch detected before the underlying soft error is identified). Nguyen’s system then applies different handling procedures based on this determination, either initiating a recovery routine or resetting the system. Petitioner argued that implementing Nguyen’s logic for determining recoverability within Bigbee’s firmware framework would render the challenged claims obvious.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine the teachings of Bigbee and Nguyen to improve system reliability and availability. Petitioner argued it was well-known that different types of errors require different responses; attempting to recover from a non-recoverable error risks data corruption, while unnecessarily resetting the system for a recoverable error reduces system availability. A POSITA reviewing Bigbee’s system would recognize the lack of differentiated error handling as a deficiency and would look to solutions like Nguyen, which explicitly addresses how to determine recoverability to create a more robust and efficient fault-tolerant system.
    • Expectation of Success: Petitioner argued a POSITA would have a reasonable expectation of success in combining the references. Implementing logical steps in firmware was a common and well-understood practice. Bigbee’s system is based on industry standards like ACPI and includes firmware abstraction layers (e.g., PAL, SAL), which would make it straightforward for a POSITA using ordinary programming skill to integrate Nguyen’s logic for determining recoverability into Bigbee's existing firmware structure.

4. Key Claim Construction Positions

  • "Detection of Loss of Lockstep" and "Detecting Loss of Lockstep": Petitioner argued these terms should be construed to include not only the detection of an actual mismatch between processor outputs but also the detection of an error within an individual processor that is a "precursor to lockstep mismatch." This construction is allegedly supported by the specification and dependent claims and is critical because the prior art, including Bigbee, explicitly teaches detecting such precursor errors as a form of loss of lockstep detection.
  • "Lockstep Is Recoverable" and "Loss of Lockstep Is Recoverable": Petitioner proposed these terms be construed to mean "lockstep is recoverable from the detected loss of lockstep." This construction links the determination of recoverability to the specific type of error that was detected, which aligns with the teachings of Nguyen and is central to the obviousness argument that different detected errors warrant different recovery responses.

5. Arguments Regarding Discretionary Denial

  • Discretionary Denial under §314(a) (Fintiv): Petitioner argued that discretionary denial under Fintiv would be inappropriate. At the time of filing, the real parties-in-interest had not been served in parallel district court litigation, no pre-trial conference had occurred, and no trial date had been set. Therefore, Petitioner contended that the factors weigh against denial and in favor of institution.
  • Discretionary Denial under §325(d): Petitioner asserted that denial under §325(d) would be improper because the petition presents new prior art and arguments not considered during prosecution. Specifically, Nguyen was never before the examiner. Petitioner argued that even though Bigbee was cited in an Information Disclosure Statement (IDS), it was never substantively applied in a rejection. The combination of Bigbee and Nguyen is argued to render obvious the very subject matter the examiner found allowable—"determining if a lockstep mismatch has occurred" in the context of recoverability. Furthermore, Petitioner argued this ground is not cumulative of a recently filed ex parte reexamination by a third party, as that proceeding does not rely on the critical teachings of Nguyen.

6. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-8 and 13-22 of the ’958 patent as unpatentable under 35 U.S.C. §103.