// HACKER NEWS — CYBERSECURITY
Xanadu was waiting for agents
Nelson was a pioneer in computing, and in 1965 he coined the word hypertext as part of the project that would define his career: Project Xanadu. With Xanadu, he had a specific vision of what computing could be, which he called the docuverse. He imagined a system that could keep every version of a document; hypertext links would know both their source and destination, and quotations would be kept by reference (rather than copy) so any included text maintained its identity and source. Everything, in this version of computing, would be intertwingled and xanalogical. We're talking about attribution down to the span.
To be xanalogical is to follow two rules: Never copy, always reference (also known by a Nelsonism, transclusion). Never overwrite, always version. As Nelson designed it, Xanadu would manage the system's complexity and massive bookkeeping burden itself, so users only experienced the benefits of a system that could never forget.
The vision of unlimited bookkeeping requires the reality of unlimited storage and a future-proof naming scheme, neither of which existed for the decades that Nelson worked on Xanadu. So when web technology exploded in the '90s, developers bypassed xanalogical computing in favor of ease: links are simple strings which break if their target moves. Maintenance became users' problems — instead of the system's responsibility — but it was easy for anyone to ship fast, and they did. Xanadu faded from the promise of a new era into computing's most famous vaporware.
Nelson has spent his career explaining that the web is a flattened parody of what hypertext was meant to be. He's right, but it didn't matter because people didn't actually need to be able to follow every link or compare every version. We're a restless species, and more inclined to follow the links or read the versions we see others pursuing. Flat was good enough.
What makes an agent an awkward collaborator also makes it a perfect citizen for Nelson's system. Agents can follow more layers of subtext than people can hold in their heads at once, such as the sources behind a quotation, any discussion around it, and stack traces attached to the exact code that ran. A fragment-based representation makes those references lossless, so each layer stays attached to the same span as the text changes. Agents can read these dimensions together, cite them so humans can audit their work, and patiently follow every link, every time. But those links need to actually exist somewhere in order for an agent to find them.
When I revisit Nelson's vision now, I recognize DeltaDB's design goals and the promise of Delta. After decades of squashing history to meet the limits of the human attention span, we're in a new reality that would be better served by something more... xanalogical.
A few years ago I wrote about watching Engelbart's 1968 demo and my realization that to build a collaborative editor, his team had to invent everything it would rely on: a new programming language, operating system, and displays.
Nelson had the same problem (but with way less funding than Engelbart enjoyed). He couldn't build Xanadu because most of its parts didn't exist, such as a way to name content that no authority issues, or storage cheap enough to never delete. His teams hand-built their own data structures for years, but the project died on the vine. Wired depicted Nelson's story as one of mismanagement, but I think he'd just specified Xanadu decades before its dependency tree existed.
We can build Delta today because sixty years of other people's roadmaps delivered the docuverse's missing pieces: kernel development, photo storage, serverless cold starts, collaborative cursors. I think it's fascinating that breakthroughs have ordinary day jobs, yet will enable the next era of computing.
A clock for a world with no center. Lamport timestamps, 1978. Every operation by every human and agent is named by an actor plus a Lamport timestamp, forever.