[net.unix] Daylight Saving Time???

avolio@grendel.UUCP (Frederick M. Avolio) (03/26/85)

> 
> Well, it seems that all 4.2BSD machines in Europe went on
> DST a week too early this year...

     One other solution --- I believe this is good for any 4.2bsd
based U*ix.  When you configure the system specify dst followed by a
number. 1 = usa, 2=australia, 3=w. europe, 4=central europe, and 5= e.
europe.
-- 
Fred Avolio      {decvax,seismo}!grendel!avolio      301/731-4100 x4227

jmrm%eng-dsl.cam@UCL-CS.ARPA (James Matheson) (03/27/85)

Leif Samuelsson writes
> Well, it seems that all 4.2BSD machines in Europe went on
> DST a week too early this year. As I see it there are three
> possible solutions:
> 
> 1) Fix and recompile ctime.c if you have sources.
> 
> 2) Remove the dst flag from the config file for a week. (Save vmunix!)
> 
> 3) Reset the date for a week. This is clearly wrong but is probably
>    the easiest way out.
> 
> Any other suggestions?

Yes, do the daylight saving time decision in a utility which calls
settimeofday() to set the timezone information appropriately. This could
be called from cron on the days when the changes occur (in England this
is the subject of annual legislation and hence not suitable to compile in);
the current value can be saved for the same utility to read and set on
reboot. The current ctime() scheme seems to make very poor use of the
flexibility provided by the timezone info in {gs}ettimeofday().

gwyn@BRL-VLD.ARPA (VLD/VMB) (03/27/85)

Another solution is to do what NBS did with WWV and change over to
using just Universal Time.

leif@erisun.UUCP (Leif Samuelsson) (03/28/85)

In article <471@grendel.UUCP> avolio@grendel.UUCP (Frederick M. Avolio) writes:
>> 
>> Well, it seems that all 4.2BSD machines in Europe went on
>> DST a week too early this year...
>
>     One other solution --- I believe this is good for any 4.2bsd
>based U*ix.  When you configure the system specify dst followed by a
>number. 1 = usa, 2=australia, 3=w. europe, 4=central europe, and 5= e.
>europe.

This isn't the problem. The code is *wrong* for group 3 and 4 of
the above. If we hadn't specified a "4" for our machine, we would
have had to wait another *month* for DST to happen. (It's this
sunday, folks!)

It's hard work to correct the code in ctime.c for a system
administrator, even with the sources, because it does not reside in
the kernel. It is linked in with every routine that deals with
time, like "date".

I think a solution would be to handle the timezone and dst
business with the "date" command and have the algorithms in the
kernel instead. That way you could specify the timezone and dst
in your /etc/rc like this:

	date -tMET -d4


Leif Samuelsson

Ericsson Information Systems AB			..mcvax!enea!erix!erisun!leif
Advanced Workstations Division
S-172 93  SUNDBYBERG				59 19 N / 17 57 E
SWEDEN

leif@erisun.UUCP (Leif Samuelsson) (03/31/85)

Well, it seems that all 4.2BSD machines in Europe went on
DST a week too early this year. As I see it there are three
possible solutions:

1) Fix and recompile ctime.c if you have sources.

2) Remove the dst flag from the config file for a week. (Save vmunix!)

3) Reset the date for a week. This is clearly wrong but is probably
   the easiest way out.

Any other suggestions?

----
Leif Samuelsson

Ericsson Information Systems AB			..mcvax!enea!erix!erisun!leif
Advanced Workstations Division
S-172 93  SUNDBYBERG				59 19 N / 17 57 E
SWEDEN