[projektfu]

FWIW, I also don't really understand what the boxes are supposed to represent, given that the arrows represent dependencies like PID <-- process. I thought a PID was an attribute of a process?

To me, a block diagram might show [CPU Scheduler], [Virtual Device Manager], [VFS Manager], [Memory Manager], [Interrupt Handlers], etc...

Of course, my knowledge of Linux internals is limited and perhaps it has a separation of the concept of PID and process where there is a literal dependency.