-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Sat, Dec 28, 2002 at 11:36:17AM +0700, David Sudjiman wrote: > Dear All, > > I was told that if I wanna sync my local date/time I should do it with > rdate <a_time_server> and then sync it with my hwclock -w. I'd use ntpd instead, it's more accurate. I recently read somewhere that if the kernel notices its internal time being synced with an external source (via ntp, for example), it will automatically adjust the hardware clock every 11 seconds, so you don't need to use hwclock. > How can I get the list of those time server? and Search google for "public ntp servers". > What is the diff with the ntpd, is that ntpd gives the query result to > some clients issued with rdate command? This is not a well-formed English sentence, so I'm not entirely sure what you're asking. But I'll try to answer it... rdate uses the RFC 868 time protocol, rather than NTP. In order to use it, you need a host that answers these queries. It's most often used on small networks to sync the times of hosts to one host considered to have the authoritative time. It's not a very accurate protocol. NTP is a much more accurate protocol. The time protocol has mostly fallen into disuse, for that reason, except perhaps at smaller sites who don't much care how accurate their system times are. NTP allows you to sync machines to extremely accurate times, controlled by (at the top tier) atomic clocks syncronized to UTC. Generally, you would syncronize one of your machines to one or more tier 2 or (usually) tier 3 servers, and sync the rest of your machines (if you have any) to that one machine. ntpd is used to keep a system syncronized, but the package also comes with ntpdate, which works a lot like rdate -- it does a one-time sync against an ntp server. You can use redhat-config-date to set up NTP time syncronization. You should probably read the NTP documentation, located in /usr/share/doc/ntp-4.1.1a, in order to make sure you have it set up correctly, and that you're being a good Netizen (i.e. nice to the public time servers, which can get quite busy). Also, in order to use most of the public servers, the site admins often expect you to send them e-mail notifying them that you are using one of their servers (usually you don't need permission in advance -- they just want to know who's using their servers). Contact info is generally provided at the same place the public NTP servers are listed. One other note: Unless you are dual-booting some version of Windows, which is brain-damaged with respect to keeping time, you should keep your hardware clock set to UTC. If you do so, and you have your time zone set properly, Linux will automatically adjust for DST changes. If you're dual-booting M$, however, Windows expects the hardware clock to be set to local time. It updates the hardware clock when a DST change occurs. I have a system that dual-boots windows, and the way I handle this is to set my hardware clock to UTC, and to set my time zone in Windows to GMT (or UTC, which is the same thing). The time displayed in Windows is wrong (but I don't use it that much so I don't care), but at least if I send e-mail from it (which I generally don't) the time stamps will reflect the correct time (albeit the wrong timezone). - -- Derek D. Martin http://www.pizzashack.org/ GPG Key ID: 0xDFBEAD02 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.7 (GNU/Linux) iD8DBQE+Dc/KHEnASN++rQIRAgGwAKCMiR6kEnBccYWVidNfcbvSvjYUrwCgpR4q fX5Xggc5cwNVXeuysI2+tMQ= =Yv/A -----END PGP SIGNATURE----- -- Psyche-list mailing list Psyche-list@redhat.com https://listman.redhat.com/mailman/listinfo/psyche-list
