How useful are collections?
Collections provide a logical grouping mechaism. Assume that you have several data objects coming out of an experiment and further assume that few of the data objects are very large containing raw data (or image) generated by the experiment and a few other data objects are small and possibly containing some meta data information about the experiment. One can logically group these data in a collection (possibly by its experiment name and timestamp) and place the collection with other ones of similar kind. Physically, the large data objects may be stored in archival storage systems or in a large-scale disk system closer to where you are planning to perform some studies on the data (ex. a disk attached to a T3E system) and the smaller data objects may be stored in a local file or database system. By logically bundling the data objects in one collection, one has a single point of access for the experimental data.
