What about stuff like udev? Or anything that has a kernel module and a controlling program running in userspace, eg. iscisiadm, mdadm etc? This way any given

What about stuff like udev? Or anything that has a kernel module and a controlling program running in userspace, eg. iscisiadm, mdadm etc? This way any given utility is free to implement and experiment with the communication protocol however they want. But, more generally, if we want general-purpose communication, why not press further and have relational database-like interface, with transactional semantics, triggers, fine-grained ownership?..