Identifiers for Digital Objects: the Case of Software Source Code Preservation

Authors : Roberto Di Cosmo, Morane Gruenpeter, Stefano Zacchiroli

In the very broad scope addressed by digital preservation initiatives, a special place belongs to the scientific and technical artifacts that we need to properly archive to enable scientific reproducibility.

For these artifacts we need identifiers that are not only unique and persistent, but also support integrity in an intrinsic way. They must provide strong guarantees that the object denoted by a given identifier will always be the same, without relying on third parties and external administrative processes.

In this article, we report on our quest for this identifiers for digital objects (IDOs), whose properties are different from, and complementary to, those of the various digital identifiers of objects (DIOs) that are in widespread use today.

We argue that both kinds of identifiers are needed and present the framework for intrinsic persistent identifiers that we have adopted in Software Heritage for preserving billions of software artifacts.

URL : https://hal.archives-ouvertes.fr/hal-01865790

Software Heritage: Why and How to Preserve Software Source Code

Authors : Roberto Di Cosmo, Stefano Zacchiroli

Software is now a key component present in all aspects of our society. Its preservation has attracted growing attention over the past years within the digital preservation community.

We claim that source code—the only representation of software that contains human readable knowledge—is a precious digital object that needs special handling: it must be a first class citizen in the preservation landscape and we need to take action immediately, given the increasingly more frequent incidents that result in permanent losses of source code collections. In this paper we present Software Heritage, an ambitious initiative to collect, preserve, and share the entire corpus of publicly accessible software source code.

We discuss the archival goals of the project, its use cases and role as a participant in the broader digital preservation ecosystem, and detail its key design decisions. We also report on the project road map and the current status of the Software Heritage archive that, as of early 2017, has collected more than 3 billion unique source code files and 700 million commits coming from more than 50 million software development projects.

URL : https://hal.archives-ouvertes.fr/hal-01590958