This version of GAMESS is constructed on top of the second version of the Distributed Data Interface (DDI). The new DDI is optimized for SMP clusters, using SystemV memory calls to implement distributed memory operations inside nodes, with network messaging between nodes. Support for processor subgroups is also included in DDI version two. The installation procedure for GAMESS now has a new, separate step for the compilation of DDI. Some systems may require reconfiguration to permit large SystemV memory allocations.