Hi monks, I've been trying to understand the program in the above post, but there is a part that I just cannot understand. I can see that the program works, I just don't know how. I cannot figure out how it knows when the queue is running a job, or queueing a job. I thought I would need to put some 'if statements' in there somewhere, otherwise how does it know, without conditionals. Please excuse my ignorance, i'm new to programming and perl and trying to understand, how this works. Could somebody try and explain to me how the hashes are being built with the correct information because to me, it looks like the times are not being compared so how does it know. Thanks.