PAR Technologies V5 manual To share a common address space within a node

Serial Task	A single process running on one of the compute nodes within the cluster.
	This process does not communicate with other processes using MPI.
	ParaStation knows about this process and where it is started from.
	A serial task may use multiple threads to execute, but all this threads have
	to share a common address space within a node.

ParaStation5 Administrator's Guide 93