An archive was a collection of records, documents, or materials that were preserved for their historical, legal, or informational value.
During Hon-Tihl's first officer's mission journal, he noted, "First Officer's journal, day 22. Exploration of the fifth planet proved to be a waste of time. This world is not worthy of a Klingon colony. All we found was a collection of energy spheres which possessed some type of telepathic archive. The spheres described an ancient power struggle that destroyed a race called the Saltah'na. We will forward our results to our science divisions." (DS9: "Dramatis Personae")