On Feb 22, 2:23 pm, markjr...@gmail.com ("Mark J. Reed") wrote: > I submit that if the inputs and outputs of Temporal are UTC, then Perl > is using UTC, not TAI. Is it TAI internally?
Only the time scale which is approved by the ITU-R for use in radio broadcasts has any international backing. Because it is the internationally-approved and broadcast time scale there are many systems which rely on its value, and for that reason it is the only practical choice for many applications and specifications. At present that time scale is called UTC, and at present it has leap seconds. If those are not suitable for an application then there is little option but to create one's own time scale with the necessary characteristics. POSIX has created its own time scale, but confusion and problems result from calling it UTC. It is probably worth pointing out that TAI is maintained only by the BIPM, and if asked the BIPM will almost certainly respond that it is not appropriate to use TAI for any standard purposes. Past objections from various folks have included metrological jargon such as TAI is "not realized" or "not available"; that only UTC is "realized". The same folks have objected to the use of GPS time because it is a US Department of Defense time scale with no international authority behind it.