F3 can be used as passive middleware
operations are always triggered by an application
stack of time series in => stack out
alternatively F3 is used as server process
waits for new data to arrive
triggers into action according to the time pattern
"Feature Processor"
from 1.1.2008 until 1.1.2009 on Mon: every 30 minutes on Sun: hourly
amazingly APIs are rather similar (hopefully)