Scalability and Availability

The HP NonStop server platform is a scalable, shared nothing, multiple processor multiprocessing environment equipped with both hardware and software configured to provide continuously available service, that is, a computing environment where failures can be tolerated without eliminating the services provided.

The heart of the NonStop platform is the multiple processor, multiple inter- processor-bus, multiple controller and multiple disk hardware configuration. No single hardware failure should eliminate processing all paths are configured as redundant by default. Since the hardware is scalable, additional resources such as CPUs and disks can be added as necessary without requiring systems engineering to redesign the machine.

Software and Application Characteristics

The software, both operating system and application, is designed to support the fault- tolerant hardware. The operating system continually monitors the status of all components, switching control as necessary to maintain operations. There are also features designed into the software to allow programs to be written as continuously available programs, that is, a pair of processes where one process performs all the primary processing and the other serves as a "hot backup", receiving updates to all data elements whenever the primary reaches a critical point in processing. Should the primary stop,...