On 2013/04/17 14:10, Ian <ian-xcs...@zsd.co.za> wrote: > Maybe there is scope for an addition to the protocol. If the logging > server could trigger an event when a packet arrives from XCSoar > after a long break. It could then send an instruction to XCSoar > "data missing from <time> to <time>". XCsoar could then extract the > missing data from its log file and resend it. The logging server > would then have to insert this data into the log file at the > required location. > > All of the above could be done separately to the native logging > protocol. Perhaps using tcp, even on a different port. The > functionality could be enabled/disabled on either the logging > server, XCSoar, or both.
Not a bad idea. That would be possible, and our "flags" attribute has room left for one bit to enable this feature. That way, the decision could be completely client-side However, we don't use TCP for a good reason - TCP requires a three-way handshake, and that's often not possible with flaky networks. There's no problem with using UDP for this, as you can see in the "friends tracking" protocol extension (since XCSoar 6.5). > PS: Is there any compression of the data before it is sent? No. It's hard to imagine how 48 bytes can be compressed. However it would be possible to implement a smaller "GPS fix" datagram by omitting many of the rarely used fields (like "airspeed" or "ENL"). Maybe we could go slightly below 40 bytes, but I'm not sure if that's worth the trouble. Max ------------------------------------------------------------------------------ Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ Xcsoar-user mailing list Xcsoar-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xcsoar-user
