timezone setting

Smoot Carl-Mitchell smoot at tic.com
Tue Mar 24 20:48:57 UTC 2009

On Tue, 2009-03-24 at 19:51 +0000, Aart Koelewijn wrote:
> On Tue, 24 Mar 2009 15:46:37 +0000, Nik N wrote:
> >> ... Well we used to call it [Greenwich] Mean Time. So just set the time
> >> to London England about and it will be right.
> > 
> > (Well, my users might then conclude that the server is actually located
> > in Britain; this would definitely rub them the wrong way!  :)
> > 
> > As somebody else correctly noticed, if that was done, the issue of
> > "daylight saving" would again invalidate the idea of ALL geographically
> > dispersed but cooperating computers running on the same time.
> > 
> Well, afaik the Linux kernel keeps the systemtime in UTC. This is then 
> corrected by the value in /etc/timezone to the local time. I wonder, but 
> it might be that when you delete/rename /etc/timezone the only known time 
> in your computer might be utc, it will not know how to "correct" it to 
> local time.

All internal timestamps are kept in UTC.  This has been the case since
Unix was invented.  All the timezone file does is display the time in
whatever timezone you want with all the historic idiosyncracies of each
timezone accounted for.  The file /etc/localtime is what sets the local
time information. It is a copy of one of the zoneinfo files found
in /usr/share/zoneinfo.  /etc/timezone has the relative pathname of the
zoneinfo file currently in use.  If you remove /etc/localtime, the
timezone is set by default to UTC.
Smoot Carl-Mitchell
Computer Systems and
Network Consultant
smoot at tic.com
+1 480 922 7313
cell: +1 602 421 9005

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