Jonathan Hill has posted the video of his recent presentation at the Atlanta PHP User Group, "Multi-tasking in PHP".
When it comes to multi-tasking and interacting with the operating system, PHP is no lightweight. In this December 6, 2012 presentation Jonathon Hill (@compwright) explores PHP's little-known POSIX, Process Control, and Semaphore extensions and shows you how to introduce a parallel dimension to your applications.
His presentation covers the use of multi-tasking to accomplish some common tasks in PHP (like batch processing or creating daemons). He talks about multi-processing vs multi-threading, forking, race conditions and semaphores.
You can watch the video of the presentation over on Vimeo and check out the software and links to other resources mentioned in the talk in this link bundle.