05317752 is referenced by 210 patents and cites 32 patents.

A fault-tolerant computer system employs a power supply system including a battery backup so that upon AC power failure the system can execute an orderly shutdown, saving state to disk. A restart procedure restores the state existing at the time of power failure if the AC power has been restored by the time the shutdown is completed. This powerfail/autorestart procedure may be implemented in a fault-tolerant multiprocessor configuration having multiple identical CPUs executing the same instruction stream, with multiple, identical memory modules in the address space of the CPUs storing duplicates of the same data. The system detects faults in the CPUs and memory modules, and places a faulty unit offline while continuing to operate using the good units. The multiple CPUs are loosely synchronized, as by detecting events such as memory references and stalling any CPU ahead of others until all execute the function simultaneously; interrupts can be synchronized by ensuring that all CPUs implement the interrupt at the same point in their instruction stream. Memory references via the separate CPU-to-memory busses are voted at the three separate ports of each of the memory modules. I/O functions are implemented using two identical I/O busses, each of which is separately coupled to only one of the memory modules. A number of I/O processors are coupled to both I/O busses. I/O devices are accessed through a pair of identical (redundant) I/O processors, but only one is designated to actively control a given device; in case of failure of one I/O processor, however, an I/O device can be accessed by the other one without system shutdown.

Title
Fault-tolerant computer system with auto-restart after power-fall
Application Number
455127
Publication Number
5317752
Application Date
November 16, 1992
Publication Date
May 31, 1994
Inventor
Nikhil A Mehta
Austin
TX, US
Peter C Norwood
Austin
TX, US
Dave Aldridge
Lago Vista
TX, US
Phil Webster
Austin
TX, US
Douglas E Jewett
Austin
TX, US
Agent
Graham & James
Assignee
Tandem Computers Incorporated
CA, US
IPC
G06F 11/00
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