Unique name for each child process in parallel R

I would like to find a unique name for each child process when running
computations with the parallel package in R. My goal is to do a 'poor
mans' parallel output where each process writes to its own file. I can
get the nodename with Sys.info()['nodename'] but I have 8 processes
for each node. I can't seem to find a way to identify each process
uniquely.

Thanks,
Cameron

P.S. Cross posted this on SO
http://stackoverflow.com/questions/25814139/unique-name-for-each-child-process-in-parallel-r