Should We Preserve the World's Software History, And Can We?

Cultural heritage is the legacy of physical artifacts and intangible attributes of a group or society that a re inherited from past generations, maintained in the present and bestowed for the benefit of future generations. What role does software play in it? We claim that software source code is an important product of human creativity, and embodies a growing part of our scientific, organisational and technological knowledge: it is a part of our cultural heritage, and it is our collective responsibility to ensure that it is not lost. Preserving the history of software is also a key enabler for reproducibility of research, and as a means to foster better and more secure software for society. This is the mission of Software Heritage, a non-profit organization dedicated to building the universal archive of software source code, catering to the needs of science, industry and culture, for the benefit of society as a whole. In this keynote talk we survey the principles and key technology used in the archive that contains over 12 billion unique source code files from some 180 millions projects worldwide.