Key goals in the development of HP-UX 11i were availability and reliability. Dynamically tunable kernel parameters are just one feature that provides high availability within HP-UX 11i. This feature entails the ability to change tunable values without rebooting the system.
In addition to dynamic tunable kernel parameters, the system has built into it dynamic processor resilience (DPR) and dynamic memory resilience (DMR). HP has an implementation that uses software, not hardware, within the operating system to perform DPR and DMR. HP's implementation of these two features keeps the system up and running while deallocating the failed memory or CPU. HP-UX 11i also offers online addition and replacement of I/O and networking cards and dynamic patching.