Abstract

Modern software systems are built by composing components drawn from large repositories, whose size and complexity is increasing at a very fast pace. A fundamental challenge for the maintainability and the scalability of such software systems is the ability to quickly identify the components that can or cannot be installed together: this is the co-installability problem, which is related to boolean satisfiability and is known to be algorithmically hard. This joint work with Jerome Vouillon presents a novel approach to the problem, based on semantic preserving graph-theoretic transformations, that allows to extract from a concrete component repository a much smaller one with a simpler structure, but equivalent co-installability properties. This smaller repository can be displayed in a way that provides a concise view of the co-installability issues in the original repository, or used as a basis for studying various problems related to co-installability, and in particular the evolution of co-installability during repository evolution. This approach has been extensively tested on GNU /Linux distributions, but can be applied to a large class of component based systems.

And then reserve for an informal discussion the work that has been organised around the MISC solver competition for improving the quality of package installers like apt-get for Debian (and that can be quite relevant for Opam :-))

Bio: Roberto Di Cosmo (http://www.dicosmo.org) holds a PhD in Computer Science and is currently Computer Science professor at University Paris Diderot, after teaching for almost a decade at Ecole Normale Supérieure in Paris, and spending a few years at INRIA .

His long term research interest in theoretical computing range from functional programming, parallel and distributed programming, the semantics of programming languages, type systems, rewriting and linear logic. More recently, he focused on new scientific problems posed by the general adoption of Free Software, with a particular focus on static analysis of large software collections, that were at the core of the Mancoosi european project (www.mancoosi.org).

Following the evolution of our society under the impact of IT with great interest, he is a long term Free Software advocate, contributing to its adoption since 1998 with books, seminars, articles and software. After creating the Free Software thematic group of Systematic in October 2007, he is currently director of IRILL (www.irill.org), a research structure dedicated to Free and Open Source Software quality.