The HP Integrity NonStop NS1000 is a clustered system that ships only in high availability and software fault-tolerant configurations. This system, along with the other NonStop servers from HP, is the evolution of Tandem Computers that began in 1975. By migrating the NonStop operating system to industry standard processors, the features and functions have been carried over to a new generation of Intel Itanium-based processors. Revenue from the NonStop servers declined slightly (about 2% in 2006 according to the HP Annual Report 2006) due in part to the migration to a new hardware platform.

While not designed for every enterprise environment, the NS1000 offers a proven system for mission-critical requirements without having to create the system from scratch as is required with other clustering systems. No additional software, management tools, or hardware is required for the NS1000 to provide a fault-tolerant server.