The parallelization of those modules is described in  and is based on
fork() and Unix sockets. Except setting
PARNODES which triggers the environment variable
SMPCPUS, nothing has to be set in addition. Alternatively, the binaries can be called with
-smpcpus <N> command line option or with the keyword
$smp_cpus in the control file.
The total memory used in such parallel calculations is approximately the amount of $ricore plus the number of CPUs times $maxcor.