Scaling in the structure of directory trees in a computer cluster

TL;DR

This paper investigates the topological structure of user-created directory trees in a computer cluster, revealing scale-free degree distributions and universal community size exponents, modeled by a simple growth process.

Contribution

It introduces a growth model that captures the directory tree structures with a single parameter, explaining the observed degree and community size distributions.

Findings

Directory trees exhibit broad, scale-free degree distributions.

A simple growth model accurately describes the directory structures.

Community size distributions follow a universal exponent.

Abstract

We describe the topological structure and the underlying organization principles of the directories created by users of a computer cluster when storing his/her own files. We analyze degree distributions, average distance between files, distribution of communities and allometric scaling exponents of the directory trees. We find that users create trees with a broad, scale-free degree distribution. The structure of the directories is well captured by a growth model with a single parameter. The degree distribution of the different trees has a non-universal exponent associated with different values of the parameter of the model. However, the distribution of community sizes has a universal exponent analytically obtained from our model.