In typical Xanadu fashion it was kept secret, protected by Dark Magick:
> He who transgresses against the propriety of the Information contained herein shall be Cursed! Woe unto all who reveal the Secrets contained herein for they shall be Hunted unto the Ends of the Universe. They shall be afflicted unto the Tenth Generation with Lawyers. Their Corporate Bodies shall be Broken and cast into the Pit. Their Corporate Veil shall be Pierced, and Liability shall attach to the Malefactors in personem. They shall suffer Ulcers and Migraines and Agonies Unimagined. Yea, Verily, for such shall come to pass against all who would Dare to Test the Powers of Xanadu unto their Doom.
It was believed to have been lost forever but in 2019 he found the only known remaining copy, a printout he had at home buried in old stuff, and posted it with OCR in his blog. He wrote:
> At the time, we regarded all the internal details of how Xanadu worked as deep and dark trade secrets, mostly because in that pre- open source era we were stupid about intellectual property. As a consequence of this foolish secretive stance, it was never widely circulated and subsequently disappeared into the archives, apparently lost for all time. Until today!
I took it and made a cleaned-up augmented HTML edition, with additions like Engelbart’s structural statement numbers which allow linking to individual paragraphs:
https://sentido-labs.com/en/library/201904240732/Xanadu%20Hy...
It includes a glossary of terms and detailed explanation of the content addressing “tumblers”, and is the best technical description of Xanadu that I know of.
You can link between documents, too, like the web, and all links are multi-ended, so you can see who referred to what.
All of this is kept consistent, like an SQL database with atomic transactions.
The original documents are confusing because the concepts needed to build Xanadu didn't really exist then. Nelson also introduced new terminology never used elsewhere, and mostly not implemented. Now we have consistent databases, CRDTs, links, and the Web as a model, plus lots of cheap bandwidth and storage. So we know how to talk about and build this stuff.
And a whole new era of questions. Who owns the weights when an LLM is trained on Xanadu?
You could build it, but no one would come.
There's no embedded markup. Links and formatting is off to the side in other documents, referencing locations in the original document.
You also have "transclusions," where you say "in document A position A.n, embed part of document B from position B.n to position B.p."
By using transclusions, you can make new versions of documents, without messing up the links and formatting codes even though they aren't embedded and reference by character position. Because you're not editing any original documents, anyone can effectively make changes. You can add a link to a page without even making a new version, you just put a new link in a side document.