Three architectural strata
Objects, identity, messages, protocols, reflection, capabilities, persistence, distribution, authority, and change—the conditions for belonging to the System-128 world.
Execution, scheduling, naming, discovery, storage, workspaces, networking, devices, graphics, input, security, versioning, and realization.
Reusable models and collaborations for software development, technical writing, publishing, graphic design, video, and future activities.
Organizing rules
Models own meaning; tools provide views and operations over models.
Roles are compositions of reusable protocol families, not sealed applications.
Every major subsystem presents a published object protocol; implementations may vary and evolve independently.
Classes remain valuable implementation units, but they no longer carry the entire architectural meaning. A class should contain only behavior belonging to its declared responsibilities; unrelated work is delegated to collaborators. This produces smaller classes and a larger, more intelligible population of focused objects.