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 and method for managing errors in a pair of lockstep processors. The system uses firmware to detect a loss of lockstep (LOL), determine if the LOL is recoverable, and then coordinate with an operating system (using ACPI methods) to attempt recovery or crash 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 fault-tolerant data processing system with all the core components of the challenged claims, including lockstep processor pairs (termed functional redundancy check or FRC mode), firmware, and an operating system that uses firmware to recover from a loss of lockstep. However, Petitioner argued Bigbee fails to explicitly teach the step of "determining if the lockstep is recoverable." Petitioner contended that Nguyen remedies this deficiency by disclosing a high-reliability processor system that explicitly determines whether a detected error (e.g., a soft error vs. a mismatch error) is recoverable and then selects a corresponding handling mechanism—either a recovery routine or a system reset. The combination of Bigbee's system architecture with Nguyen's error recoverability determination logic allegedly renders the claimed invention obvious.
    • Motivation to Combine: A POSITA would combine Bigbee and Nguyen to improve system reliability and availability. The prior art recognized that handling recoverable and non-recoverable errors differently was critical; 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 would have recognized the gap in Bigbee's disclosure and would have looked to solutions like Nguyen to implement a determination step, thereby creating a more robust and efficient fault-tolerant system.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success in combining the references. Implementing logical steps for error handling in firmware was a common and well-understood practice. Bigbee’s system, being ACPI-compliant, provided a standardized framework (including ACPI BIOS, PAL, and SAL layers) that a POSITA could have readily programmed using ordinary skill to incorporate Nguyen's logic for determining error recoverability. The implementation would have been a predictable application of known techniques.

4. Key Claim Construction Positions

  • "Detection of Loss of Lockstep" / "Detecting Loss of Lockstep": Petitioner argued these terms should be construed to include not only an actual "lockstep mismatch error" but also the detection of an error that is a "precursor to lockstep mismatch" (e.g., corrupt data in one processor that has not yet caused a divergent output). This broader construction, supported by the specification and dependent claims, allows prior art that detects precursor errors to satisfy this limitation.
  • "Lockstep Is Recoverable" / "Loss of Lockstep Is Recoverable": Petitioner asserted these terms should be construed to mean "lockstep is recoverable from the detected loss of lockstep." This construction links the recoverability determination directly to the specific error that was detected, which is central to mapping Nguyen's teachings onto the claims.

5. Arguments Regarding Discretionary Denial

  • §314(a) (Fintiv): Petitioner argued against discretionary denial under Fintiv, stating that the parallel district court litigation is in its earliest stages. Key factors supporting institution included that the real parties-in-interest had not yet been served in that litigation, no pre-trial conference had occurred, and no trial date had been set.
  • §325(d): Petitioner contended that denial would be inappropriate because the petition presents new prior art and arguments not previously considered by the USPTO. Specifically, the combination of Bigbee in view of Nguyen was never before the examiner. Although Bigbee was cited in an IDS during prosecution, it was never substantively discussed or used in a rejection. Nguyen, which provides the critical missing element of determining recoverability, was never presented to the examiner at all. Petitioner also noted that a pending ex parte reexamination filed by a third party is not cumulative because it does not rely on the 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.