Internship Subject Proposal

Distributed algorithms are known for being tedious to design and assess. Since they are based on the interaction of several independent components, they are hard to envision for the sequential human brains. Deadlocks, race conditions and resource starvation are unfortunately common problems of distributed computing. Model checking is one of the most successful techniques to assess that a distributed algorithm exhibits the expected properties. The main idea is to exhaustively build and analyse the state space of an algorithm and check that the requirements are satisfied for all possible executions. For a distributed algorithm, all possible interleavings of the different processes will be analyzed. Usually, the users of such methods are expected to express a formalization of their algorithm using a mathematical formalism such as TLA+ [1]. In order to remain usable by non-specialist and also to reduce the possibility of bug introduction during the manual translation between the mathematical formalism of TLA+ and a more programming oriented one, Lamport introduced the PlusCal [2] language. The algorithms are expressed in a natural manner and then converted automatically to TLA+ using a dedicated compiler. We recently extended PlusCal to a 2.0 version easing the expression of distributed algorithms in addition to the concurrent algorithms targeted by the original version.