[tz] Beginner's help request

Daniel Ford dfnojunk at gmail.com
Wed Nov 1 01:47:58 UTC 2017


Thanks for your comments, which come as a bit of a shock to me!

Given that the TZdb is possibly the only *source* data on time zones/DST that is updated periodically (most other 'sources' are *derived from* the TZdb), I would have expected that lots of people would wish to access it when they have a need for current DST information (such as all those derivative websites).

"The intent is that you download the information once, and then resend it to your users."  But this contradicts the statement in README that says: "It is updated periodically to reflect changes made by political bodies to time zone boundaries, UTC offsets, and daylight-saving rules."  That infers that users (including all those derivative websites) must *periodically* access the TZdb data to ensure the rules they use are current!  Especially since, as David Patte pointed out, some jurisdictions change their rules multiple times in a year, with little notice!

"...since you can massage the data before sending it to your users."  I am not set up to send anything, other than posting a piece of hardware (my clock) to a purchaser.  After that, it's up to the clock to keep itself updated on TZ/DST rules for its destination locale, using its wi-fi access to a suitable information source (as well as regularly checking UTC time from an NTP server, of course).  It was my intention that the clock would access the TZdb about once per week to check the latest rules.

And all the clocks (assuming I sell more than a few!) will access at different times.  The intention is to program the clock to check the TZdb every, say, 169 hours since boot-up (the extra hour ensures it doesn't happen at the same time every week, as further 'randomisation').

Another reason I wouldn't want to set up a website to serve these clocks is that this is just a hobby project (though I hope to sell a few clocks via eBay), and any website I set up would only last as long as I do.  While I don't expect to die in the next few years (I'm only 73!), it could happen, and where would that leave those clock owners?

More about this in my response to Zefram...


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