How much of the archive actually exists and how much is just raw data? I have a book deposited in the LoC and BL but as far as I know, the copy in the LoC is a digital copy. I think the one at the BL is real since it got the title of my chapter right (I had “Content is not Context” and half the online versions call it “Content is Context” instead), but I’m not 100% sure. All of it is raw data. Data is far more compact and usable than hardcopy. The originals and any relevant artifacts are still in the possession of their respective people.
An archivist obtains a new record (book, media file, journal entry, a new scan of something, a field report from a research team, etc) and it is then verified. Once it has been determined as true it is entered into The Locus where it is archived. The Locus is pretty much constantly updating all of the mirror sites. But it can take a while for a mirror to be updated due to the vast volumes of information involved. Things make their way into The Locus from the various offices of the archives across the Federation. The official Federation mirrors are also used to hold and buffer the new information.