The Road to an Archival Data Format—Data Structures

Abstract

The current data formatting and labeling standards for the Planetary Data System (PDS) are known as the PDS4 Standards. They supersede the PDS3 Standards, but they represent a complete redesign of the requirements and implementation, rather than even a major incremental revision, from the previous standard. At the heart of the PDS4 Standards lies a fundamental, philosophical change from the PDS3 paradigm: the PDS4 Standards clearly and specifically constrain the way that the bytes comprising observational data may be stored in their data files—that is, the data structures—to a much greater degree than the PDS3 Standards ever did, even in their most mature realization. In PDS4, the PDS has defined data structures optimized for the long-term preservation of observational data. We explore the history of the PDS and its standards through the examination of a single, simple data structure (the 2D image), to understand the evolutionary pressures on the data and on the PDS that led to the development of the archival data structure requirements for observational data at the core of the PDS4 standards.