Who invented vector clocks?
decomposition.al
Who invented vector clocks?
1–10 of 40 posts
Re: Who invented vector clocks?
#2It depends on your reference frame...
Re: Who invented vector clocks?
#3> So, the current version of the Wikipedia page on vector clocks is wrong, or at least misleading, about the origin of the idea, and it’s kind of my fault.
No. 0% fault of the author and 100% the fault of the Wikipedia editor. Generally speaking, people who are unwilling to ensure the accuracy of their work don't deserve the privilege to do that work.
Re: Who invented vector clocks?
#4> The idea of vector timestamps was developed independently by Ladin and Liskov [LL86].
A few years ago when I ended up down the rabbit hole on CRDTs and alternatives I learned of Liskov’s work on time vectors, which is still my top “things you didn’t know about Barbara Liskov” fact.
Re: Who invented vector clocks?
#5> So, the current version of the Wikipedia page on vector clocks is wrong, or at least misleading, about the origin of the idea, and it’s kind of my fault. No. 0% fault of the author and 100% the fault of the Wikipedia editor. Generally speaking, people who are unwilling to ensure the accuracy of their work don't deserve the privilege to do that work.
> Generally speaking, people who are unwilling to ensure the accuracy of their work don't deserve the privilege to do that work.
This is all volunteer labor. Anyone can be a volunteer if they'd like. Wikipedia encourages mistakes (or "boldness") and assumes that due to a network of volunteers and the density of interest, an article will eventually become better.
Programming docs in open source often have errors. Do the volunteers not deserve the "privilege" of offering their time for free?
Re: Who invented vector clocks?
#6This is a good example of how academic citation practices subtly launder out the role of compute, trial-and-error, and practitioners in favor of academia. OP concludes that if you want to cite Fidge & Mattern for credit for 'developing the theory', that's fine. But notice, that's not how it started and is an answer to a different - no one was asking, 'who finally explained why vector clocks work in a rigorous way', the very title is 'who invented vector clocks' (repeated in the first sentence, and in various forms thereafter as 'system...developed', 'introduced', 'idea...developed', etc), and she objects to WP describing her as uncovering who really 'invented' vector clocks. The actual answer to her question would seem to be Parker 1983. (And looking at the description of 'LOCUS' in https://pages.cs.wisc.edu/~remzi/Classes/739/Papers/parker83... , it sounds more like they are reverse-engineering why LOCUS works...)
Re: Who invented vector clocks?
#7It's interesting to see someone trying to decide the invention clock in the real world...
Re: Who invented vector clocks?
#8Vector clocks are pretty neat. I didn't invent them but I used a crude approximation when I was designing what was to become NIS+ at Sun Microsystems.
Given the problem that you want to accept updates to a database at multiple servers but cannot guarantee that all of those servers have the same notion of time and thus creating an accurate mutation vector that leaves the state of the database consistent, NIS+ used a tuple of (update, secondary-server-time) which the primary could query the secondary and compute a time delta (positive or negative) that would allow it to sort updates to the same database entry from multiple secondaries into a primary relative time order. It could then apply the updates and produce deltas for all secondaries which would apply any necessary changes to their database.
As a systems problem I really enjoyed the challenge.
Re: Who invented vector clocks?
#9It depends on your reference frame...
Unlikely: assuming all of the authors of the various papers were on earth at the time, the spacetime intervals separating their discoveries were almost certainly timelike, in which case there is no ambiguity in their ordering. Unless they were within a few ms of each other (in the earth's reference frame).
Re: Who invented vector clocks?
#10It depends on your reference frame...
Unlikely: assuming all of the authors of the various papers were on earth at the time, the spacetime intervals separating their discoveries were almost certainly timelike, in which case there is no ambiguity in their ordering. Unless they were within a few ms of each other (in the earth's reference frame).
But (taking the joke closer towards absurdity) when using vector timestamps independent actions by people not communicating with each other don't have a well-defined order.