On Thu, 2009-08-06 at 10:53 +0800, John Summerfield wrote: > I have regularly seen files timestamped "in the future" after > installation, and I don't do anything extraordinary. I always run my > computers' clocks on local time. > I have always assumed, "Stupid Americans, they always think the rest of > the world does things their way." Actually, running the RTC on localtime is very much a legacy Microsoft limitation / attitude. So the allegedly "stupid American way" is actually to run your RTC on localtime. Open systems have traditionally run their RTC on UTC. The idea is that you offset everything, system, application, user, etc... localtime, from UTC, which is the RTC. Here's the general rule of thumb ... - All RTCs and most "real-time" stamps should be made in UTC - Events should be made in the specific timezone they are local to Remember, timezones change, and even timezone rules (offsets) change. UTC does not. Hence why RTCs should be UTC always, and most real-time events stamped on UTC. Events, on the other hand, will always be in localtime, so they should always be stored in localtime with the reference timezone. Again, because timezones and timezone rules change, offsets should be made from that stored localtime. E.g., calendar events. It's confusing at first, until you think through the logic. Although one, very required detail to the logic is that you keep your timezone information (offset) up-to-date, so it is aware of any changes to rules. Otherwise you run into the real issue where your localtime is either incorrect (because the offset is incorrect), or people are changing the localtime to the correct (which makes the UTC incorrect, because the offset is incorrect). UTC is absolute for RTC Localtime is absolute for events (local to the timezone) -- Bryan J Smith Senior Consultant Red Hat, Inc. Professional Consulting http://www.redhat.com/consulting mailto:bjs@xxxxxxxxxx +1 (407) 489-7013 (Mobile) mailto:b.j.smith@xxxxxxxx (Blackberry / Red Hat External) --------------------------------------------------------- You already know Red Hat as the entity dedicated to 100% no-IP-strings-attached, community software development. But do you know where CIOs rate Red Hat versus other software and services firms for their own, direct needs? It's no comparison: http://www.redhat.com/promo/vendor/ _______________________________________________ Kickstart-list mailing list Kickstart-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/kickstart-list
