41 research outputs found
A case study for reversible computing: Reversible debugging of concurrent programs
Reversible computing allows one to run programs not only in the usual forward direction, but also backward. A main application area for reversible computing is debugging, where one can use reversibility to go backward from a visible misbehaviour towards the bug causing it. While reversible debugging of sequential systems is well understood, reversible debugging of concurrent and distributed systems is less settled. We present here two approaches for debugging concurrent programs, one based on backtracking, which undoes actions in reverse order of execution, and one based on causal consistency, which allows one to undo any action provided that its consequences, if any, are undone beforehand. The first approach tackles an imperative language with shared memory, while the second one considers a core of the functional message-passing language Erlang. Both the approaches are based on solid formal foundations
Controlling Reversibility in Reversing Petri Nets with Application to Wireless Communications
Petri nets are a formalism for modelling and reasoning about the behaviour of
distributed systems. Recently, a reversible approach to Petri nets, Reversing
Petri Nets (RPN), has been proposed, allowing transitions to be reversed
spontaneously in or out of causal order. In this work we propose an approach
for controlling the reversal of actions of an RPN, by associating transitions
with conditions whose satisfaction/violation allows the execution of
transitions in the forward/reversed direction, respectively. We illustrate the
framework with a model of a novel, distributed algorithm for antenna selection
in distributed antenna arrays.Comment: RC 201
Reversibility in Chemical Reactions
open access bookIn this chapter we give an overview of techniques for the
modelling and reasoning about reversibility of systems, including outof-
causal-order reversibility, as it appears in chemical reactions. We consider
the autoprotolysis of water reaction, and model it with the Calculus
of Covalent Bonding, the Bonding Calculus, and Reversing Petri Nets.
This exercise demonstrates that the formalisms, developed for expressing
advanced forms of reversibility, are able to model autoprotolysis of
water very accurately. Characteristics and expressiveness of the three
formalisms are discussed and illustrated
An axiomatic approach to reversible computation
Undoing computations of a concurrent system is beneficial inmany situations, e.g., in reversible debugging of multi-threaded programsand in recovery from errors due to optimistic execution in parallel dis-crete event simulation. A number of approaches have been proposed forhow to reverse formal models of concurrent computation including pro-cess calculi such as CCS, languages like Erlang, prime eventstructuresand occurrence nets. However it has not been settled what properties areversible system should enjoy, nor how the various properties that havebeen suggested, such as the parabolic lemma and the causal-consistencyproperty, are related. We contribute to a solution to these issues by usinga generic labelled transition system equipped with a relationcapturingwhether transitions are independent to explore the implications betweenthese properties. In particular, we show how they are derivable from aset of axioms. Our intention is that when establishing properties of someformalism it will be easier to verify the axioms rather than proving prop-erties such as the parabolic lemma directly. We also introduce two newnotions related to causal consistent reversibility, namely causal safetyand causal liveness, and show that they are derivable from our axioms
Axiomatizing GSOS with termination
We discuss a combination of GSOS-type structural operational semantics with explicit termination, that we call the tagh-format (tagh being short for termination and GSOS hybrid). The tagh-format distinguishes between transition and termination rules, but allows besides active and negative premises as in GSOS, also for, what is called terminating and passive arguments. We extend the result of Aceto, Bloom and Vaandrager on the automatic generation of sound and complete axiomatizations for GSOS to the setting of tagh-transition systems. The construction of the equational theory is based upon the notion of a smooth and distinctive operation, which have been generalized from GSOS to tagh. We prove the soundness of the synthesized laws and show their completeness modulo bisimulation. The examples provided indicate a signi cant, though yet not ideal, improvement over the axiomatization techniques known so far