System.Time.Clock Design Issues

Ashley Yakeley ashley at
Tue Feb 8 02:20:44 EST 2005

In article 
 David Menendez <zednenem at> wrote:

> 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.

No. Date and clock times are usually UTC or some offset (time-zone) 
thereof. Converting to TAI requires a table of leap-seconds.

Ashley Yakeley, Seattle WA

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