Computer-Assisted Verification of an Algorithm for Concurrent Timestamps

A formal representation and machine-checked proof are given for the Bounded Concurrent Timestamp (BCTS) algorithm of Dolev and Shavit. The proof uses invariant assertions and a forward simulation mapping to a corresponding Unbounded Concurrent Timestamp (UCTS) algorithm, following a strategy developed by Gawlick, Lynch, and Shavit. The proof was produced interactively, using the Larch Prover. Keywords Verification, validation and testing; tools and tool support; Larch; input/output automata; concurrent timestamps 1 INTRODUCTION In this paper, we describe a computer-assisted verification, using the Larch Prover (Garland and Guttag, 1991), of one of the most complicated algorithms in the distributed systems theory literature: the Bounded Concurrent Timestamp (BCTS) algorithm of Dolev and Shavit (1989). This algorithm runs in the single-writer, multi-reader, read/write shared memory model. The verified algorithm is a slight simplification, due to Gawlick, Lynch, and Shavit (1992), of t..