Ketil Malde writes:
Seth Kurtzberg <seth@cql.com> writes:
When you say [TAI is] "defined for all history and the future", does that mean literally what it says?
Well, as it is only a clock (counting SI seconds), it is unambigously defined. It is not a calendar, so you need a separate calendar to name days and years for you, and to perform the mapping between TAI's seconds and calendar entities.
As I understand it, TAI and UTC can both be described in terms of a clock counting SI seconds. The difference is that a TAI day is always 86400 seconds long, whereas a UTC day can be 86399 - 86401 seconds, depending on which second it is. Using TAI, we can always convert a date and clock time to a count of seconds and vice-versa without any additional information. To do the same with UTC, we need a table of leap-seconds. -- David Menendez <zednenem@psualum.com> <http://www.eyrie.org/~zednenem/>