el are designed to work with IVOA data discovery 
protocols (e.g. TAP, SIA, and SSA) that are applicable to observational data and to 
support providing support for IVOA data models (e.g. ObsCore) with minimal extra effort.</p>

<h2>Data Access</h2>

<p>Data access is supported by the Artifact class and, for more specialised cases, the 
Part and Chunk classes. Artifacts are stored data objects (usually files). The structure of
an artifact is described by it part(s) and the data content of the a part is desc