/ history

Overview: E's History

The above diagram does not show all the major influences between these systems. It only shows the influences relevant to the creation of E, or of systems derived from E.

The blue nodes & green arcs are those that have "capability nature", even though most of these systems were not capability secure, and were not conceived of by their inventors as having any relationship to capabilities or security. Nevertheless, these are the systems to study in order to gain insight into the nature of capability computation. Of the blue nodes, the ones in italics are actual capability systems. Of the green arcs, the thicker light-green ones show the most influencial paths. The thicker light-green arcs below E lead to systems that were derived from E in their original conception. The others are retrofits of E concepts into existing systems.

The loop: E and EROS have influenced each other. Both directly, and through our love child, CapIDL.

Capability-Based Computer Systems by Henry Levy is the classic old book surveying old capability systems, with an emphasis on their implementations. The whole book is now online at the above link. It provides a good historical perspective of the non-Actors, pre-KeyKOS world of capabilities. This earlier work is represented in the above diagram only by Hydra.