If the pvmd breaks, you may need to start it under a debugger. The master pvmd can be started by hand under a debugger, and the PVM console started on another terminal. To start a slave pvmd under a debugger, use the manual startup (so=ms) host file option so the master pvmd will allow you to start the slave by hand. Or, use the dx= host file option to execute a script similar to lib/debugger, and run the pvmd in a debugger in an xterm window.