A Calculus of Consistent Component-based Software Updates

TL;DR

This paper introduces a formal calculus called updateπ, based on higher-order π calculus, to model and reason about dynamic, component-based software updates, focusing on safety, timing, and state transformation.

Contribution

It develops a language-independent formal model for dynamic software updates, addressing key aspects like granularity, timing, and recovery, with semantics that demonstrate its expressive power.

Findings

Defines a formal calculus for component updates

Models safe update processes with reduction semantics

Shows the calculus's expressive power through semantics

Abstract

It is important to enable reasoning about the meaning and possible effects of updates to ensure that the updated system operates correctly. A formal, mathematical model of dynamic update should be developed, in order to understand by both users and implementors of update technology what design choices can be considered. In this paper, we define a formal calculus $update\pi$, a variant extension of higher-order $\pi$ calculus, to model dynamic updates of component-based software, which is language and technology independent. The calculus focuses on following main concepts: proper granularity of update, timing of dynamic update, state transformation between versions, update failure check and recovery. We describe a series of rule on safe component updates to model some general processes of dynamic update and discuss its reduction semantics coincides with a labelled transition system semantics that illustrate the expressive power of these calculi.