Re: [LEAPSECS] What problems do leap seconds *really* create?

From: William Thompson <thompson_at_orpheus.nascom.nasa.gov>
Date: Thu, 30 Jan 2003 10:47:45 -0500

Ken Pizzini wrote:
>
> On Wed, Jan 29, 2003 at 07:04:23PM +0000, Markus Kuhn wrote:
> > Who really needs to maintain a full list of leap seconds and for what
> > application exactly?
>
> If a file storage system stores timestamps as "SI seconds since
> some epoch", and a legal question arises about whether a given
> document was stored on that system before or after midnight on
> some given date, the logic which converts the timestamp to a
> UTC date will need to know how many leap seconds to adjust for,
> which in the general case means that the logic converting these
> file-timestamps into UTC will need a full list of leap seconds.

In fact, that is exactly what we do in the software used to command the CDS
instrument aboard the SOHO spacecraft. The user always works in UTC time, but
the times are stored internally as double precision floating point values
representing the number of TAI seconds since 1-Jan-1958. The same procedure is
used in the catalog of observations taken.

William Thompson
Received on Thu Jan 30 2003 - 07:47:53 PST