2.2 The Galaxy Software Architecture on OpenVMS Compaq's first implementation of the APMP model of com- puting is the Galaxy Software Architecture on OpenVMS, which uses APMP to execute multiple instances of OpenVMS in a single computer. Software logically partitions CPUs, memory, and I/O ports by assigning them to individual instances of the OpenVMS operating system. This partitioning, which a system man- ager directs, is a software function; no hardware boundaries are required. Each individual instance has the resources it needs to execute independently. An OpenVMS Galaxy envi- ronment is adaptive in that resources such as CPUs can be dynamically reassigned to different instances of OpenVMS.