Where did you see random PIDs ? I think all (most?) Linux distros use sequental.
in reply to Re^4: forkManager PID 1 less than top
in thread forkManager PID 1 less than top
Process IDs are usually allocated on a sequential basis
I am running Ubuntu with 3.8 kernal, PIDs are sequental.
Also, I think there can be problems with some software, when recently-used PID re-used too fast.