[Coco] NitrOS-9/OS-9 feature suggestion

[William Astle]

Doing timezones correctly is *hard*. Not only do you have changing 
offsets from UTC, but you have all the random rules for handling DST or 
not depending on the location. And the best part is that the specific 
handling of time zones also depends on the specific time being handled 
since the definitions change over time.

There is a crazy amount of data related to timezones that is kept by 
Linux and other systems. Linux has no idea where it is located. The time 
zone is set by simply selecting a time zone which selects a specific 
data file to be used for identifying all the rules for figuring out the 
local time.

On 2015-08-09 09:35, John Guin wrote:
> I fought with time zones while I was on the Exchange and Outlook teams with Microsoft for more than 10 years.
>
> The last I saw, there were somewhere around 157 time zones that Exchange/OL supported.  They constantly change (Venezuela was a great example - they decided mid week to change their time zone during the next weekend) and North Korea just announced they were changing their time zone this week.  I doubt OS-9 is used much in either country, though.  It still leads to an interesting political/legal view on which time zones you want to support.
>
> Katmandu also has a 15 minute offset.
>
> Sounds like a fun, challenging project that would make the implementor(s) think about the world more than the code/feature being implemented.
>
> If you want a different perspective, read the last chapters of this book:  http://www.amazon.com/Dreaming-Code-Programmers-Transcendent-Software/dp/1400082471/ref=sr_1_1?ie=UTF8&qid=1439134365&sr=8-1&keywords=dreaming+in+code  Essentially, time zones are what killed that project.
>
> Good feature request!
>
> -----Original Message-----
> From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of George Ramsower
> Sent: Saturday, August 8, 2015 11:45 PM
> To: coco at maltedmedia.com
> Subject: Re: [Coco] NitrOS-9/OS-9 feature suggestion
>
> On 8/9/2015 12:33 AM, K. Pruitt wrote:
>> So New Zealand is +12:45 minutes off of GMT.
>>
>> Couldn't be off on the hour, or even the half hour. Had to be off on
>> the three quarters of the hour mark.
>>
>> Way to make things difficult, New Zealand.
>>
>> How does Linux store basic time zone info and also does Linux now
>> store location info (lat and long coordinates)?
>>
>>
>> ----- Original Message ----- From: "K. Pruitt"
>> Sent: Saturday, August 08, 2015 9:43 PM
>> Subject: [Coco] NitrOS-9/OS-9 feature suggestion
>>
>>
>>> I think a flag somewhere in the system would be useful to indicate
>>> the CoCo's time-zone.
>>>
>>> This could be very useful for a lot of time-based utilities.
>>>
>>> Perhaps the offset from GMT along with the status of DST stored in a
>>> file in the SYS directory?
>>>
>>> It would have to be a standard to be truly useful.
>>>
>>>
>>>
>>
>>
>    I was looking into this very subject a few days ago. There are several locations of odd time zones.
>    Do a Google for "world time zones" and you will find many with odd time offsets.
>
> George R.
>
>
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