### Design Rules and Abstraction (from branching and real time)

#### Abstract

Three simple models of synchronous hardware are given; using linear
discrete, branching discrete and branching real time.
A simple notion of abstraction is introduced, motivated by the need to
ultimately view such models as scientific theories that make empirical
predictions. It makes the significance of design rules explicit.
Two abstractions from the branching discrete to the linear discrete
model are given. They shed some light on the roles of consistency, deadlock and
determinacy.
The stronger of the two depends on a notion of dynamic type for
processes which ensures deadlock freedom.

A reasonably strong abstraction from the branching real to the
branching discrete model is given. This depends on a finer notion of
type which is a reasonably physically plausible formalisation of the timing
properties of certain real components.

Back to my home page.