Infrastructure Overlays and Digital Chimeras: Keys for Reading Information Infrastructures

The paper studies the relationship between infrastructures and their corresponding information infrastructures. It introduces the concept of infrastructure overlay, i.e., a generic object that encapsulates complexity within an infrastructure, and of digital chimera, i.e., for any given overlay instance, the collection of its representations in the information systems of actors that own, use, or for some reason encounter the instance in the infrastructure. Examples are the container overlay in cargo infrastructures and the interbank transfer overlay in financial infrastructures. Overlays exist in a world where goods and assets are transported or traded, i.e., the analogical world. What can be said about their digital alter-egos, partitioned, distributed among a number of information systems, and managed piece-wise according to heterogeneous rules? Based on two cases that unrolled in Swiss agriculture between 2016 and 2019, and on the subsequent study of dependencies between information systems, of digital dependency feedback to information system operators, and of the notion of shared distributed functionality, the paper defines a conceptual framework within which actors and information systems can be meaningfully positioned in an infrastructure relatively to analogical objects and their digital representations. The paper presents several overlay-chimera pairs with different characteristics and clarifies the role of software-based platforms that have been proposed as the building blocks of information infrastructures. It suggests that overlays should be designed (or, in case that they seem to already exist, should at least be well identified and understood), before their digital chimeras are developed and deployed at large.