SMCI_PORTS

   On systems running OpenVMS Galaxy software, the Shared Memory
   Cluster Interconnect (SMCI) system parameter SMCI_PORTS controls
   initial loading of SYS$PBDRIVER. This parameter is a bit mask;
   bits 0 through 25 each represent a controller letter. If bit 0
   is set, which is the default setting, PBAx is loaded (where x
   represents the Galaxy Partition ID). If bit 1 is set, PBBx is
   loaded, and so on up to bit 25, which causes PBZx to be loaded.
   For OpenVMS Alpha Version 7.2 and later, VSI recommends leaving
   this parameter at the default value of 1.

   Loading additional ports allows multiple paths between Galaxy
   instances. In the initial release of the Galaxy software, having
   multiple communications channels is not an advantage because
   SYS$PBDRIVER does not support fast path. A future release
   of OpenVMS will provide Fast Path support for SYS$PBDRIVER,
   when multiple CPUs improve throughput by providing multiple
   communications channels between instances.