An overview of D-I algebra

An overview is given of D-I algebra, an algebra for the specification of the safety and progress properties of delay-insensitive circuits in terms of voltage-level transitions on wires. The algebraic laws make it possible to specify circuits concisely and facilitate the verification of designs. Individual components can be composed into circuits in which signals along internal wires are hidden from the environment. A delay-insensitive approach has been successfully applied to several nontrivial designs, such as the design of a packet router and the design of a constant response-time stack, and D-I algebra has played an important role both in suggesting decompositions and in verifying them.