Re: Alternatives
I would say:
* make it like daylight changes only on Sat/Sun night (no less often than once a year, no more often than twice a year), e.g mid June and mid Dec
* also standardize very specific time window and slew procedure (say, one hour 00:00UTC - 01:00UTC) to be applied by all NTP servers and by all machines maintaining their own time
* anyone who really cares about precise time will apply TAI anyway
* from standarized slew procedure, accurate relation between TAI and UTC can be derived at any point during slew window (as well as after and before)
Weak point of my proposal that conversion between TAI and UTC will be more complex than it is now (due to slew), but it standarizes current practice and by virtue of this standarization it makes time between different sources comparable again. If exercised often enough, the kinks will be ironed out eventually.
Biting the hand that feeds IT
