At the simplest level, the experimental data is simply a collection of files (Datafiles), which are grouped in to Datasets, which are grouped in to Experiments:
(Please note that the schema is only partially shown in the diagram above)
At the top level, Tardis stores a flat list of Experiments. Each Experiment contains one or more Datasets, and each Dataset contains one or more Datafiles.
At each level, Experiment, Dataset and Datafile, user defined parameters may be added, grouped in to Parameter Sets.
Tardis doesn’t impose any interpretation on what is considered an Experiment or Dataset. Examples of how datasets may be grouped are: by sample, by instrument settings, or as a time sequence, e.g. artificially aging a material and investigating the effects.
In the last post I listed two metadata hierarchies: 1) The Core, Discipline and Project hierarchy from the University of Southampton, and 2) the Core, Instrument and Science hierarchy from STFC. The core metadata schema is hard-coded in Tardis. The Instrument, Science and Project schema’s can all be implemented using Parameter Sets.