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LAFS Tesla Coils & Corpses, 2014-08-01 ====================================== in attendance: Zooko (scribe), Taylor, Nathan, Brian Example of servers with disjoint sets. If the reader uses union on read, then each server (or coalition thereof) gets to choose whether their uniquely-held elements will be included or excluded from the reader's view. This bothers Zooko. Because "editorial" or "filtering and selection" power is close to *write* power in Zooko's mind. (ref. The Library of Babel, Daniel Dennett's version) Taylor suggested "biggest set" instead of union, unanimity, majority, etc. Zooko likes the idea!! Brian suggested that good adders who like to limit the freedom of the servers could be expected to download the previous set or remember the previous set in their local state. Brian suggested that the servers could enforce upon the adders that they don't send add commands without a proof of knowledge of the current version. But we decided against that because the "lob an element into the set, even though I don't know anything about the set" is a valid use case. (Example: a write-intensive workload like secure distributed logging, where the performance and availability consequences of requiring read-before-every-write would be intolerable.) The protocol for uploading has to require adders to provide the transitive closure of elephants in case the server doesn't already have them. Should that be an interactive protocol or…? We talked about Two-Phase-Commit. It can eliminate (assuming correct implementation) a single server entering a broken state due to a partially-applied update. It can *reduce*, but not eliminate version skew between servers, where some of the servers have (atomically) updated to the new version and others have (atomically) rolled-back to the current version. We talked about building distributed ledgers on top of add-only sets. Nathan is keen on this idea of using add-only sets as a primitive building-block for Bitcoin-like distributed ledger systems. Then we started talking about our plans for a cryptocurrency startup… -- Regards, Zooko Wilcox-O'Hearn Founder, CEO, and Customer Support Rep https://LeastAuthority.com Freedom matters. _______________________________________________ tahoe-dev mailing list tahoe-dev@tahoe-lafs.org https://tahoe-lafs.org/cgi-bin/mailman/listinfo/tahoe-dev
