Sequoia: A Fault-Tolerant Tightly Coupled Multiprocessor for Transaction Processing

  • Authors:
  • Philip A. Bernstein

  • Affiliations:
  • Digital Equipment Corp., Cambridge, MA

  • Venue:
  • Computer
  • Year:
  • 1988

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Abstract

The Sequoia computer is a tightly coupled multiprocessor that avoids most of the fault-tolerance disadvantages of tight coupling by using a fault-tolerant hardware-design approach. An overview is give of how the hardware architecture and operating system (OS) work together to provide a high degree of fault tolerance with good system performance. A description of hardware is followed by a discussion of the multiprocessor synchronization problem. Kernel support for fault recovery and the recovery process itself are examined. It is shown the kernel, through a combination of locking, shadowed memory, and controlled flushing of non-write-through cache, maintains a consistent main memory state recoverable from any single-point failure. The user shared memory is also discussed.