Can a user start multiple pvm daemons per user and machine, e.g. 4 processor machine with 2 parallel jobs of the same user.
A new feature in PVM 3.4.4 is the concept of a "Virtual Machine ID". You can now set the PVM_VMID environment variable to an arbitrary string (or use the
"id=" option in a host file, see man page for pvmd3), and this will distinguish and allow multiple virtual machines to run on the same set of hosts under
the same userid. (This feature was originally introduced by SGI in their commercial PVM product, and has now been generalized for the public PVM system.)
This feature seems to be something that people often want, and the PVM_VMID is the cleanest way to provide this functionality, rather than overloading the
SHAREDTMP compiler flag and other internals.
Setting the PVM_VMID environment variable before starting PVM will create an encapsulated virtual machine with the given VMID name. By default, all other
hosts which are added to this virtual machine will inherit the same VMID. If hosts are added to the virtual machine which are running older versions of
PVM (prior to 3.4.4), then the VMID will be ignored for those hosts, and hence these machines can only be added to one virtual machine for the given user.
The VMIDneed not be consistent on every host in a virtual machine (althoughthis is not necessarily advisable), and the VMID can be set for individual
hosts using the "id=" host file option (see man page for pvmd3).