BT tested this when it was back in beta status.
Basically, HPSPO is a kind of halfway between no protection, and the old full-on storage protection.
You split up your storage pools so that no pool has both user and system storage. User storage is then put into a different
MVS storage key, so that if a user program tries to overwrite system-owned storage it will fail. HPSPO won't stop
a task overwriting another task's storage.
As far as performance goes, the overhead of having HPSPO on is negligible.
I
Iain Robertson British Telecom
Tel : 020 8456 7108
iain.dk.robertson@bt.com
pp2.11, Watford TE, Exchange Road, Watford, WD18 0GB