11. Shared Memory Cluster Interconnect (SMCI) The Shared Memory Cluster Interconnect (SMCI) is an SCS port for communications between Galaxy instances. When an OpenVMS instance is booted as both a Galaxy and as an OpenVMS Cluster, the Shared Memory Cluster Interconnect driver will be loaded. This SCS port driver will communi- cate to other cluster instances in the same Galaxy through shared memory. This capability provides one of the ma- jor performance benefits of the OpenVMS Galaxy Software Architecture. The ability to communicate to another clus- tered instance through shared memory provides dramatic performance benefits over traditional cluster interconnects.