29 research outputs found
Formal verification of a theory of packages
Over the years, open source distributions have become increasingly largeand complex—as an example, the latest Debian distribution contains almost 30 000packages.Consequently, the tools that deal with these distribution have also become more andmore complex. Furthermore, to deal with increasing distribution sizes optimisationhas become more important as well.To make sure that correctness is not sacrificed for complexity and optimisation, it isimportant to verify the underlying assumptions formally.In this paper, we present an example of such a verification: a formalisation in Coqof a theory of packages and their interdependencies
Managing software uninstall with negative trust
A problematic aspect of software management systems in view of integrity preservation is the handling, approval, tracking and eventual execution of change requests. In the context of the relation between clients and repositories, trust can help identifying all packages required by the intended installation. Negative trust, in turn, can be used to approach the complementary problem induced by removing packages. In this paper we offer a logic for negative trust which allows to identify admissible and no-longer admissible software packages in the current installation profile in view of uninstall processes. We provide a simple working example and the system is formally verified using the Coq theorem prover
Frontiera reale e frontiera metaforica nelle opere degli emigrati italiani in Svizzera
Nelle oltre 250 opere letterarie scritte da emigrati italiani in Svizzera è quasi sempre presente il concetto di frontiera. Ma con il passare del tempo e a seconda dei generi, la frontiera, da discrimine fra un prima e un dopo, da luogo di un trauma spesso rimosso, si trasforma in metafora di un percorso di formazione compiuto ora atraverso il dolore e la malattia, ora attraverso la spiritualità e la solidarietà .The frontier concept is omnipresent in over 250 literary works by Italian émigrés in Switzerland. But with the passage of time and the deline of the genre to a position of secondary importance, the frontier, from a form of discriminating between before and after, of displacing trauma, has been transformed into a metaphor of distance, of preparation either through pain and disease, or through spirituality and solidarity
Minimizing transitive trust threats in software management systems
We consider security threats in software installation processes, posed by transitively trusted dependencies between packages from distinct repositories. To analyse them, we present SecureNDC, a Coq implemented calculus using an explicit trust function to bridge repository access and software package installation rights. Thereby, we resolve a version of the minimum install problem under trust conditions on repositorie
Strong Dependencies between Software Components
Component-based systems often describe context requirements in terms of
explicit inter-component dependencies. Studying large instances of such
systems?such as free and open source software (FOSS) distributions?in terms of
declared dependencies between packages is appealing. It is however also
misleading when the language to express dependencies is as expressive as
boolean formulae, which is often the case. In such settings, a more appropriate
notion of component dependency exists: strong dependency. This paper introduces
such notion as a first step towards modeling semantic, rather then syntactic,
inter-component relationships. Furthermore, a notion of component sensitivity
is derived from strong dependencies, with ap- plications to quality assurance
and to the evaluation of upgrade risks. An empirical study of strong
dependencies and sensitivity is presented, in the context of one of the
largest, freely available, component-based system
Comparison of PBO solvers in a dependency solving domain
Linux package managers have to deal with dependencies and conflicts of
packages required to be installed by the user. As an NP-complete problem, this
is a hard task to solve. In this context, several approaches have been pursued.
Apt-pbo is a package manager based on the apt project that encodes the
dependency solving problem as a pseudo-Boolean optimization (PBO) problem. This
paper compares different PBO solvers and their effectiveness on solving the
dependency solving problem.Comment: In Proceedings LoCoCo 2010, arXiv:1007.083
MIRTO: an open-source robotic platform for education
This paper introduces the MIddlesex RoboTic platfOrm (MIRTO), an open-source platform that has been used for teaching First Year Computer Science students since the academic year 2013/2014, with the aim of providing a physical manifestation of Software Engineering concepts that are often delivered using only abstract or synthetic case studies. In this paper we provide a detailed description of the platform, whose hardware specifications and software libraries are all released open source; we describe a number of teaching usages of the platform, report students’ projects, and evaluate some of its aspects in terms of effectiveness, usability, and maintenance