Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!usenet.killfile.org!.POSTED!not-for-mail From: c28f62@TheWorld.com (Mark Kramer) Newsgroups: comp.os.linux.misc,comp.sys.raspberry-pi Subject: Re: Keeping 'order' without RTC. Date: Tue, 12 May 2015 06:14:47 +0000 (UTC) Organization: The World : www.TheWorld.com : Since 1989 Lines: 28 Message-ID: References: NNTP-Posting-Host: shell01.theworld.com X-Trace: flea.killfile.org 1431411287 5880 192.74.137.71 (12 May 2015 06:14:47 GMT) X-Complaints-To: news@usenet.killfile.org X-Newsreader: trn 4.0-test72 (19 April 1999) Xref: csiph.com comp.os.linux.misc:14764 In article , William Unruh wrote: >Agreed. But there is still a well defined algorithm. The RTC is worse. >As far as I know, it never takes leap seconds into account. Of course it doesn't. It's a simple device. >Fortunately it is usually recalibrated on shutdown, It may be set on shutdown, or it may be set more often. There is no "calibration". >so the system, which should take >leap seconds into account ( although I am not sure Windows does) can >reinitialise the RTC. The system doesn't know leap seconds either. It counts interrupts. There are demons that run on the system that monitor external time sources, like an NTP demon would. Windows (since at least NT and XP) have NTP clients built in, so in your terminology, yes, of course "Windows" takes leap seconnds into account. It may not do that for a week, but it will eventually do it. If you are that interested in keeping up with leap seconds and are using Windows, then you will almost certainly be using a more frequent update interval for the Windows internal NTP client, or be using a third-party client.