Method for specifying a system having a plurality of interconnected functional modules, each representing a respective abstract-state based machine, and a system so specified

A hardware digital data processing system comprising

• a) a plurality of distinct hierarchically arranged and interconnected hardware digital data processing modules each embodying a respective abstract state-based-machine, wherein
• i) each non-top first module comprises:
• A) a transformer link, connecting to a single second module at a next higher level, for enabling a relevant change-of-state of the first module,
• B) an observer link from the second module for receiving a state enquiry signal, and
• C) an event link to the second module for outputting a solicited event signal,
• D) means for retrosignalling an internal autonomous step, and
• ii) each non-bottom module is, as such second module, interconnected to one or more lower level modules, each of which then functions as such first module, and
• iii) a top module is arranged for signal interchanging with an environment,
• b) a single step scheduler for autonomously rendering each said step executable in said first module, and
• c) entering means for, under control of a preconditioning transformer signal received from said second module, entering said step into said scheduler.

At least one medium, readable by at least one data processing device, the medium embodying a plurality of interconnected functional modules organized into hierarchical levels, each module embodying a respective abstract state-based machine, the embodiment comprising the following embodied in the medium:

• a single step scheduler;
• at least one non-top level first module comprising respective link means to a single second module at a next higher level, the link means comprising
• a transformer link for enabling a change of state of the first module responsive to the second module;
• an observer link for receiving a state inquiry signal from the second module;
• an event link for outputting a solicited event signal to the second module;
• retrosignalling means for retrosignalling the internal autonomously executed step;
• at least one non-bottom module, including the second module, each non-bottom module comprising at least one interface for accommodating the link means from at least one relevant one of the at least one non-top level first module, at least one of the non-bottom modules being a top module, the top module comprising means for signal exchanging with an environment;
• wherein
• the at least one non-top first module enters each said step in the step scheduler in order to render such step autonomously executable in response to a preconditioning transformer signal received from said second module.