> Does PPS tell us anything about the actual source of time? Not really.
> Or does that just mean "time from a serial port"? Even that is only a "probably". PPS is "pulse per second"; it does not provide time per se, but does provide a reference for where the boundaries between seconds fall, thereby allowing refinement of approximate time obtained from elsewhere. A PPS signal could come in over a parallel port, a dedicated GPIO pin, or pretty much anything else imagination can dream up. Of course, PPS-based time is only as good as the source of the PPS pulses, the hardware to accept them, and the software infrastructure to use them. I would hope that anyone running a stratum-1 server based on a PPS signal would go to some lengths to make sure the resulting time is good, but of course nothing actually *prevents* someone from setting up a PPS setup with a bad reference signal, bad hardware, and/or bad software, and advertising the resulting server as stratum 1. (If used in a sane setup, it will be tossed out by the selection algorithms once it's drifted a little, of course, but that's a separate issue.) /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML [EMAIL PROTECTED] / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B _______________________________________________ timekeepers mailing list [email protected] https://fortytwo.ch/mailman/cgi-bin/listinfo/timekeepers
