Abstract: A method and system for containing a fault in a network node. A loss of all remaining communication links from a node is detected. A time duration from the loss of a first remaining communication link to the loss of a last remaining communication link is determined. It is established that the node has contained a fault when the time duration for the loss of the first remaining communication link to the loss of the last remaining communication link is not more than a predetermined amount of time.

Abstract: A method and system for containing a fault in a network node. A loss of all remaining communication links from a node is detected. A time duration from the loss of a first remaining communication link to the loss of a last remaining communication link is determined. It is established that the node has contained a fault when the time duration for the loss of the first remaining communication link to the loss of the last remaining communication link is not more than a predetermined amount of time.

Abstract: A method and apparatus for receiving status information from shared logical memory modules in a computer system including redundant memory. The status information includes whether the shared logical memory modules are in a transitional state and the number of logical memory modules in the mirror set. When shared logical memory modules are added or removed from redundant memory they go through a transitional state when the memory card may respond to a request for data held on the card, but that data may be unreliable. Checking this status information allows better error checking of data and fault detection of the shared logical memory module.

Abstract: A method and apparatus for receiving status information from shared logical memory modules in a computer system including redundant memory. The status information includes whether the shared logical memory modules are in a transitional state and the number of logical memory modules in the mirror set. When shared logical memory modules are added or removed from redundant memory they go through a transitional state when the memory card may respond to a request for data held on the card, but that data may be unreliable. Checking this status information allows better error checking of data and fault detection of the shared logical memory module.

Abstract: A method and circuit utilizing first and second tag bits for granting access to a block of memory in a multiprocessor system having a shared memory are provided. When a memory request for exclusive access to a block of memory is granted, the starting address for that block of memory is placed in a register bank, thereby opening a semaphore. The starting address of a memory block of a subsequent memory access request is compared with the starting addresses corresponding to open semaphores within the register bank and access is denied to the requested block of memory if a match is found. The starting address associated with a request which is denied access is placed in a temporary buffer and the request is later granted access after the corresponding open semaphore becomes closed. A request which is granted memory access to a memory block which results in an open semaphore, has exclusive access to that block of memory until the semaphore is closed.

Abstract: A process for the production of zirconium tetrachloride from dissociated zircon in which gaseous chlorine is passed through pellets consisting of ground dissociated zircon, carbon and a binder at a temperature in the range of from 450.degree. to 800.degree. C. The zirconium tetrachloride produced contains less than about 0.22% by weight, calculated as SiO.sub.2, of silicon tetrachloride.