Abstract: A fault tolerant computer system and method are disclosed. The system may include a plurality of CPU nodes, each including: a processor and a memory; at least two IO domains, wherein at least one of the IO domains is designated an active IO domain performing communication functions for the active CPU nodes; and a switching fabric connecting each CPU node to each IO domain. One CPU node is designated a standby CPU node and the remainder are designated as active CPU nodes. If a failure, a beginning of a failure, or a predicted failure occurs in an active node, the state and memory of the active CPU node are transferred to the standby CPU node which becomes the new active CPU node. If a failure occurs in an active IO domain, the communication functions performed by the failing active IO domain are transferred to the other IO domain.

Abstract: A fault tolerant computer system and method are disclosed. The system may include a plurality of CPU nodes, each including: a processor and a memory; at least two IO domains, wherein at least one of the IO domains is designated an active IO domain performing communication functions for the active CPU nodes; and a switching fabric connecting each CPU node to each IO domain. One CPU node is designated a standby CPU node and the remainder are designated as active CPU nodes. If a failure, a beginning of a failure, or a predicted failure occurs in an active node, the state and memory of the active CPU node are transferred to the standby CPU node which becomes the new active CPU node. If a failure occurs in an active IO domain, the communication functions performed by the failing active IO domain are transferred to the other IO domain.

Abstract: A fault tolerant computer system and method are disclosed. The system may include a plurality of CPU nodes, each including: a processor and a memory; at least two IO domains, wherein at least one of the IO domains is designated an active IO domain performing communication functions for the active CPU nodes; and a switching fabric connecting each CPU node to each IO domain. One CPU node is designated a standby CPU node and the remainder are designated as active CPU nodes. If a failure, a beginning of a failure, or a predicted failure occurs in an active node, the state and memory of the active CPU node are transferred to the standby CPU node which becomes the new active CPU node. If a failure occurs in an active IO domain, the communication functions performed by the failing active IO domain are transferred to the other IO domain.

Abstract: An architecture and coherency protocol for use in a large SMP computer system includes a hierarchical switch structure which allows for a number of multi-processor nodes to be coupled to the switch to operate at an optimum performance. Within each multi-processor node, a simultaneous buffering system is provided that allows all of the processors of the multi-processor node to operate at peak performance. A memory is shared among the nodes, with a portion of the memory resident at each of the multi-processor nodes. Each of the multi-processor nodes includes a number of elements for maintaining memory coherency, including a victim cache, a directory and a transaction tracking table. The victim cache allows for selective updates of victim data destined for memory stored at a remote multi-processing node, thereby improving the overall performance of memory.