On Oct 28, 2015, at 5:23 PM, Lester Caine <lester@lsces.co.uk> wrote:
On 29/10/15 00:12, Guy Harris wrote:
The major problem all the time is identifying just what rules were applied when processing historic data, which may actually only be a current meeting diary. If by "historic data" you mean "pre-1970 data", I'm not sure why that would be needed for a current meeting diary, and it's not the major problem *all* the time, it's a problem for people using the tzdb to try to convert between UTC ("proleptic UTC"?) and local time for times prior to the Epoch, which might be a significant subset of the users of the tzdb, but it's still a (proper) subset of those users.
See my other post ... If a user only has a post-1970 TZ set of data but then looks at some historic material they see the wrong times and possibly dates. Agreed it would not affect many people, but with the growing interest in family history it's a growing area of interest.
If a user has a *full* TZ set of data and then looks at some historic material they may see the wrong times and possibly dates, if the pre-1970 information is wrong. :-)