Simon Willison’s Weblog

3 items tagged “crdt”


Notes on Apple’s Notes app keeps its data in a SQLite database at ~/Library/Group\ Containers/—but it’s pretty difficult to extract data from. It turns out the note text is stored as a gzipped protocol buffers object in the ZICNOTEDATA.ZDATA column. Steve Dunham did the hard work of figuring out how it all works—the complexity stems from Apple’s use of CRDT’s to support seamless multiple edits from different devices. # 9th December 2021, 10:39 pm


I was wrong. CRDTs are the future (via) Joseph Gentle has been working on collaborative editors since being a developer on Google Wave back in 2010, later building ShareJS. He’s used Operational Transforms throughout, due to their performance and memory benefits over CRDTs (Conflict-free replicated data types)—but the latest work in that space from Martin Kleppmann and other researchers has seen him finally switch allegiance to these newer algorithms. As a long-time fan of collaborative editing (ever since the Hydra/SubEthaEdit days) I thoroughly enjoyed this as an update on how things have evolved over the past decade. # 28th September 2020, 9:03 pm


The Xi Text Engine CRDT (via) Xi is “a modern editor with a backend written in Rust”—an open-source text editor project from Google built on some very interesting computer science (Conflict-free Replicated Data Types). It’s a native editor with server-backed synchronization as a first-class concept. # 13th October 2017, 10:32 pm