The resource manager and hoster interfaces were created in cooperation with members of the Condor project . They are used together by Condor. There was initially a single interface for both functions, but the two were logically separated because either part is generally useful.
In Condor, the scheduler is the boss of everything else. If an application attempts to reconfigure the virtual machine, PVM calls Condor through the resource manager interface to determine whether another host can be allocated, and if so, which one. The names of hosts requested refer to classes of machines, instead of specific hosts.
Pvmds and user processes can run under a borrowed login assigned to Condor, using cycles from idle workstations. If the workstation owner should return, the processes must be stopped immediately and cleared off the host in a timely manner; any temporary files must be moved as well. The hoster interface allows Condor to start slave pvmds, necessary because they are run under a Condor-owned login.