Many thanks for all the contributions to my original question. Where there is a will...there is a way!
In summary, from reading all posts, I think the best solutions for the two scenarios presented are: SENSOR APPLICATIONS: Sensors need to timestamp packets themselves e.g. a cellphone-based system can sync to NTP. So this should not be in Google's problem domain INVOICE APPLICATIONS: Use a single synchronisation object to increment numbers and adjust timestamps "artificially" to keep them in sequence. But as one wag once said...that's all very well in practice, but will it work in theory? I'm new to GAE, I wouldn't mind seeing some sample code for this solution :-) Any takers? On Jan 13, 9:24 am, "David Symonds" <dsymo...@gmail.com> wrote: > On Tue, Jan 13, 2009 at 7:25 AM, Cesium <cesiumpic...@gmail.com> wrote: > > >> What algorithm are you trying to implement that requires synchronized > >> clocks? To my knowledge it's a pretty well-known best-practice to > >> never rely on clocks being the same across a distributed system. Some > >> algorithms can take advantage of closely correlated clocks, but I > >> believe they never need anything better than the guarantees of NTP > >> (http://en.wikipedia.org/wiki/Network_Time_Protocol), which is > >> essentially what App Engine provides. > > > My application requires a time stamp from GAE that differs from > > UTC by no more than 1s. (I'll worry about latencies.) > > Imagine for example, a global network of sensors that measure > > geophysical data. The usefulness of the data is degraded if there > > is a large uncertainty surrounding the sample epoch (timestamp). > > Why don't you get your sensors to track their own time? > > Dave. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
