IOA Code Generator (Making IOA Run) January 2, 2019 IOA Code Generator (Making IOA Run) Joshua A. Tauber PODC Rump Session July 17, 2000 Joint work with: Steve Garland, Nancy Lynch, Michael Tsai I O A

What Generate standard language (Java) translation of IOA program that will run in a physically distributed network Execution should be efficient No global synchronization

Why (Short term) Test bed for distributed algorithm design (Long term) Find practical method for generating code from specifications

How Make humans do hard thinking Model and use existing external services (e.g. network, console) Use library of hand-written data type implementations Stay in IOA until very last step Successive refinement Supports application of other tools

Node-Channel Form Env System Global Specification Node-Channel Form

Abstract Channels Abstract model for ease of programming (e.g., Reliable FIFO queue): Algorithm that implements abstract channel in terms of (model of) real channel: Auxiliary Automaton Real channel

Environment Implementation Delay Buffer Console Parser

Generated vs. External Automata Env Code to Generate Algorithm Channel

Code Generation Process Submit IOA program for node algorithm Generate parser automaton Compose algorithm, parser (computed), and auxiliary network automata (from library) Resolve nondeterminism in schedule Convert implicit ND to explicit ND Resolve explicit ND (programmer help) Emit target language code - Link to hand coded-datatype implementations

Truth in Advertising Assume network implements model Assumes data type implementations implement axiomatic definitions No current fault tolerance Still in progess Composer Code generator Proof of design correctness