摘要:
A computer system in a fault-tolerant configuration employs three identical CPUs executing the same instruction stream, with two identical, self-checking memory modules storing duplicates of the same data. Memory references by the three CPUs are made by three separate busses connected to three separate ports of each of the two memory modules. The three 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 three 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.
摘要:
A computer system in a fault-tolerant configuration employs three identical CPUs executing the same instruction stream, with two identical, self-checking memory modules storing duplicates of the same data. Memory references by the three CPUs are made by three separate busses connected to three separate ports of each of the two memory modules. The three 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 three 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.
摘要:
A computer system in a fault-tolerant configuration employees 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 faulty unit can be replaced and reintegrated into the system without shutdown. 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.
摘要:
A computer system in a fault-tolerant configuration employs 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 faulty unit can be replaced and reintegrated into the system without shutdown. 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.
摘要:
A computer system in a fault-tolerant configuration employs 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 faulty unit can be replaced and reintegrated into the system without shutdown. 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) 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.
摘要:
A computer system in a fault-tolerant configuration employs 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. Memory references. 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 by the multiple CPUs are voted by each of the memory modules. A private-write area is included in the shared memory space in the memory modules to allow functions such as software voting of state information unique to CPUs. All CPUs write state information to their private-write area, then all CPUs read all the private-write areas for functions such as detecting differences in interrupt cause or the like.
摘要:
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.
摘要:
A computer system in a fault-tolerant configuration employs 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 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. 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, i.e., by merely redesignating the addresses of the registers of the I/O device under instruction control.
摘要:
A computer system in a fault-tolerant configuration employs 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 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. 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, i.e., by merely redesignating the addresses of the registers of the I/O device under instruction control.
摘要:
A network-based storage system comprises one or more block-level storage servers that connect to, and provide disk storage for, one or more host computers. In one embodiment, the system is capable of subdividing the storage space of an array of disk drives into multiple storage partitions, and allocating the partitions to host computers on a network. A storage partition allocated to a particular host computer may appear as local disk drive storage to user-level processes running on the host computer.