Hi there 

If I were to use the cron expression '0 31 12/2 8/1 7/1 ? 2011/1' (I would like to schedule a job starting from 12:31pm 08/07/2011 which fires every 2 hours as an example), would this expression 

a) fire every 2 hours indefinitely or 
b) fire every 2 hours until the end of that day/month/year?

Any help would be greatly appreciated.