is a crappy little perl script originally written to detect borked NFS mounts. It's supposed to be cronned to run every minute or so, and it sets a semaphore when it's kicked off. If another copy's launched, it detects that it's already running (by seeeing a non-zero value for the key), and starts throwing a wobbly. There's a cgi to go with it, which simply checks the results file, but you don't want that.