Timezone variations

seismo!celerity!dreamit!jjw seismo!celerity!dreamit!jjw
Fri Feb 6 00:36:28 UTC 1987

After a long discussion of the variation in European timezones
seismo!mcvax!cwi.nl!dik (dik t. winter, cwi, amsterdam, nederland)
> So what is my conclusion?  It is nice to automatically switch to and from
> DST, however it must be easily possible to override the rules.  (In some
> countries in Europe during the period 1977-1982 it was not known until a
> few days in advance whether a switch would occur or not, and what day it
> would occur!)

The problem occurs when the rules are embedded in a library routine or a
difficult to change file.  If the DST rules for the local time zone are
kept in a file which can be easily and quickly edited then this can be done
very quickly when necessary by those who should know (people living in the
local time zone).

Rather than a file of rules I prefer a file of change dates along with
information about how much time is to be added or subtracted and the
appropriate time zone name.  The format should allow for partial hours,
negative savings ("daylight spending time"?) and double daylight time.

Arthur Olsen's timezone compiler generates a file of the proper type.
However, I am not sure it provides the necessary flexibility for quick
local changes of all types.

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