Abstract: Address information that is desired to be monitored of a data storage memory is stored in a data memory address buffer 110, and while a program is being executed the stored address information and address information transferred to a bus are compared. If there is coincidence between the stored address information and the address information transferred to the bus, data that has been transferred to the bus (data that has been read or written based on coincident address information) can be reliably output to the outside. As a result, it is possible to reliably carry out defect analysis for a data storage memory while a program is being executed.

Abstract: A valve assembly is provided which is particularly suitable for operation and maintenance under extreme environments. It includes a valve body, a ball valve member rotatably mounted within the valve body, a bonnet removably secured to the valve body, and seat retaining asemblies removably secured to the bonnet. Upon removal of the bonnet, the valve member and all internals are also removed as a unit so that they may be serviced at a convenient location. The seat retaining assemblies may include inclined surfaces which seat against oppositely inclined surfaces defined within the valve body. An alignment plate is secured to the seat retaining assemblies to insure proper sealing.