The use of a UTC timestamp is promoted on the grounds that a "local" time alternative may have a relationship to UTC that is "dependent on the unknown or unknowable actions of politicians or administrators."
However, the relationship between UTC and TAI (monotonically evenly increasing Atomic Time) is dependent on measurements collected by the International Earth Rotation Service (IERS), which result in the application of leap seconds to TAI to obtain UTC. In general, without access to an up to date table of leap seconds, it is not possible to determine the difference between two UTC times, since one or more leap seconds may lie between them. And, while I grant you they may not be politicians or administrators, the actions of the astronomers at the IERS are equally unknowable more than a few weeks in advance. I would argue that UTC, fixated as it is on the bobbles of a spinning ball of rock, is yet another display format, and that timestamps should be a form of Atomic Time. At the very least, it should be recognized that UTC is as unpredictable in its own way as Daylight Savings Time. cheers, Don Craig Omneon Video Networks
