Differences between version 16 and predecessor to the previous major change of TimeNotes.
Other diffs: Previous Revision, Previous Author, or view the Annotated Edit History
| Newer page: | version 16 | Last edited on Tuesday, March 21, 2006 6:58:43 pm | by LawrenceDoliveiro | Revert |
| Older page: | version 15 | Last edited on Wednesday, October 12, 2005 12:26:25 am | by AristotlePagaltzis | Revert |
@@ -6,9 +6,15 @@
</pre>
The SuperUser can use tzselect(8) to change these settings. ''Make sure'' it is set correctly! If you have it set to [UTC] your system time will not reflect your localtime. ntpdate(1) will set the system clock correctly, but the hardware clock will get confused. You can compare these by looking at the output of date(1) and hwclock(8).
-On [Debian] systems __/etc/default/rcS__ contains a __UTC__ variable that decides whether or not the hardware clock is set to [UTC]. Having it
that way and setting
__UTC=yes
__ is A Good Idea. The best reason
you might want
to use localtime for
your hardware clock is if you dual boot
with another OperatingSystem that fiddles with your hardware clock for daylight savings
.
+On [Debian] systems __/etc/default/rcS__ contains a __UTC__ variable that decides whether or not the hardware clock is set to [UTC].
+
+On [SUSE] systems, __/etc/sysconfig/clock__ defines a __HWCLOCK__ variable
that specifies the command-line option hwclock(8) for selecting the clock offset: "-u" for UTC, or "--localtime" for local time.
+
+On [RedHat] systems, __/etc/sysconfig/clock__ defines the __UTC__ variable as either
__UTC=true
__ if the hardware clock is in UTC, or __UTC=false__ if it is in local time.
+
+Having the hardware clock set to UTC
is A Good Idea, because it avoids the need to adjust the clock forward or backward an hour when daylight saving goes on or off
. There is no standard, ''reliable'' way of recognizing whether the hardware clock has been set for daylight saving or not; hence it is possible, particularly if your machine boots more than one OperatingSystem and you switch between them at the wrong time, for the adjustment to be done twice, or not at all. However,
you might be forced
to have
your hardware clock set to local time in order to maintain compatibility
with another OperatingSystem that fiddles with your hardware clock for daylight saving
.
See [UTC] and [NTP] for more.
The internal representation of [UTC] time that all Unix systems use is often know as the Unix timestamp. This value is defined as the number of seconds since 00:00.00 01-01-1970. This value is always stored in [UTC] and when displayed is adjusted via your time zone to display your local time.
