Steve O'Hara-Smith wrote: > On Mon, 25 Jun 2007 11:17:27 GMT > Roedy Green <[EMAIL PROTECTED]> wrote: > >> On Sun, 24 Jun 2007 18:14:08 -0700, [EMAIL PROTECTED] (Robert Maas, >> see http://tinyurl.com/uh3t) wrote, quoted or indirectly quoted >> someone who said : >> >>> - Stick to astronomical time, which is absolutely consistent but >>> which drifts from legal time? >> depends what you are measuring. IF you are doing astronomy, your >> advice would apply. If you are doing payrolls, you want effectively to >> pretend the leap seconds never happened, just as Java does. > > Which leaves you about 30 seconds out by now - smelly. > Easy solution: always read Zulu time directly from a recognized real-time clock and store the result in a database as a ccyymmddhhmmssfff ASCII string where fff is milliseconds). By "recognized real-time clock) that I mean an atomic clock and distribution network such as GPS or (in the UK or Germany) an MSF low frequency radio broadcast. NTP using tier-1 sources may do the job too. The clock interface may need to be JINI because most suitable receivers have serial interfaces.
This is certainly accurate for financial transactions: the UK CHAPS inter-bank network has a Rugby MSF receiver in each bank's gateway computer and uses that for all timestamps. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | -- http://mail.python.org/mailman/listinfo/python-list
