timezone.5 (2010 09)

t
timezone(5) timezone(5)
(Tunable Kernel Parameters)
NAME
timezone, dst - difference between Universal (Greenwich mean) time and Local time
VALUES
Default
timezone =
420
dst = 1
A default value of 1, indicates that the default value for the timezone tunable (420 minutes west of
Greenwich, England ) is to be interpreted as a daylight savings time value.
Allowed values
-720 to 720.
The value for the
timezone tunable should correspond to a defined time zone, and thus should be at
least a multiple of 15 minutes. More commonly the value will be a multiple of 60 or 30 minutes,
corresponding to an hour or half-hour time zone.
The value of the
dst tunable specifies if the time is with daylight savings or not. When the value is set to
1, then the system is using daylight savings time, and if it is set to
0, the system is not.
Recommended values
Any allowed value is equally recommended. However, the chosen value should correspond to the time
zone and daylight saving scheme of the system site or to a time zone and daylight saving scheme which
has meaning for applications or users.
DESCRIPTION
The
timezone tunable is the difference between Greenwich mean time (Universal Time) and local time,
expressed as minutes west of Greenwich, England. The dst tunable indicates whether the timezone
tunable is to be interpreted as a standard or daylight savings time value.
These tunables provide a way to convert between Grenwich Mean Time (or Universal Time) and local
time. Although
timezone is a tunable, it is not used to affect the behavior of the system. Rather, it is
used to remember time zone information when the system is rebooted. This information is returned by
gettimeofday under HP-UX extensions. The timezone tunable is independent of other methods of
indicating time zones. For example, date gets or sets the time in either Universal or local time by using
the TZ environment variable. In this case the timezone tunable has no effect. In general, it is best to
refer to the manpages for specific system calls such as localtime() and tzset
() to check if there is a
dependency on the
timezone tunable.
Who Is Expected to Change This Tunable?
Anyone.
Restrictions on Changing
Changes to these tunables take effect at the next reboot.
When Should the Value of This Tunable Be Changed?
These tunables may be changed to match the system’s geographic time zone or the time zone of users.
What Other Tunable Values Should Be Changed at the Same Time?
The
timezone and dst tunables should always be set and interpreted as a pair of values.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its
meaning changed in future releases of HP-UX.
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parame-
ter values. After installation, some tunable parameters may no longer be at the default or recommended
values. For information about the effects of installation on tunable values, consult the documentation for
the kernel software being installed. For information about optional kernel software that was factory
installed on your system, see HP-UX Release Notes at http://www.hp.com/go/hpux-core-docs.
AUTHOR
timezone and dst were developed by HP.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1