Bayley, Alistair Alistair_Bayley at ldn.invesco.com
Wed Jan 26 08:40:06 EST 2005

> From: Simon Marlow [mailto:simonmar at microsoft.com] 
> I like the idea of having a single notion of absolute time, which is
> independent of TAI or UTC time.  You can do arithmetic on 
> absolute time
> (add/subtract absolute units of time, find absolute time differences),
> and convert to/from TAI and UTC.

This is something I don't see any motivation for, from a user's point of
view. AFAICT, there _is_ no notion of absolute time, just time w.r.t. a
given calendar (if you view TAI and UTC as calendars). The representation of
time as "units since epoch" is "just an implementation detail" :-)

Seriously, though, what use is being able to find the difference between two
times like this? If I want the difference between two times, I want to
specify in what units the difference should be e.g. millisecs, seconds,
days, years, etc. The difference between times tA and tB might be 86400
seconds, but they might still be on the same day e.g. leap seconds, so if I
ask for (diffDays tA tB) I might get zero, one, or two, depending on the


Confidentiality Note: The information contained in this   message, and any
attachments, may contain confidential   and/or privileged material. It is
intended solely for the   person(s) or entity to which it is addressed. Any
review,   retransmission, dissemination, or taking of any action in
reliance upon this information by persons or entities other   than the
intended recipient(s) is prohibited. If you received  this in error, please
contact the sender and delete the   material from any computer.

More information about the Libraries mailing list