This module provides a gen_server controlling a Port to "rrdtool -"

rrdtool is a very nice graphing system as well as logger for time series data.
for more info on rrdtool check out:

  http://oss.oetiker.ch/rrdtool/

for more info on this, the erlrrd module see the doc directory.

Tested most frequently with R14B, older versions of erlang may or may not work
correctly.