Over time, with every OS Version change, PHP and Apache and modules change, things also changed under the hood. That's how I noticed that when I first had written my Harvester trap to play around with PHP internal semaphore function, I had to adapt my code every time a change on the OS, PHP or apache happened.
Well, got fed up with that and decided to rewrite the function to work without the semaphore and got it running nicely.
So, dear bots, you are welcome to come back to my site, not respect the robots.txt directive and get into my trap... Happy crawling !