PR/SM
In mainframe computing PR/SM ( Processor Resource/System Manager ) is a type-1 Hypervisor ( a virtual machine monitor ) that allows multiple logical partitions to share physical resources such as CPUs , I/O channels and LAN interfaces; when sharing channels , the LPARs can share I/O devices such as direct access storage devices ( DASD ) . 
<triplet> PR/SM <subj> Hypervisor <obj> instance of