jm + dates   7

RFC 3339: Date and Time on the Internet: Timestamps
the RFC take on ISO-8601. I need to update my mental bookmarks to start referring to this instead
iso8601  dates  times  datetimes  rfc  standards 
july 2015 by jm
Falsehoods programmers believe about time
I have repeatedly been confounded to discover just how many mistakes in both test and application code stem from misunderstandings or misconceptions about time. By this I mean both the interesting way in which computers handle time, and the fundamental gotchas inherent in how we humans have constructed our calendar — daylight savings being just the tip of the iceberg.

In fact I have seen so many of these misconceptions crop up in other people’s (and my own) programs that I thought it would be worthwhile to collect a list of the more common problems here.

See also the follow-up:

(via Marc)
via:marcomorain  time  dates  timezones  coding  gotchas  calendar  bugs 
october 2014 by jm
'better dates and times for Python', to fix the absurd proliferation of slightly-incompatible Python date/time types and APIs. unfortunately, applies....
python  libraries  time  dates  timestamps  timezones  apis  proliferation  iso-8601 
may 2014 by jm
Daylight saving time linked to heart attacks, study finds
Switching over to daylight saving time, and losing one hour of sleep, raised the risk of having a heart attack the following Monday by 25 per cent, compared to other Mondays during the year, according to a new US study released today. [...] The study found that heart attack risk fell 21 per cent later in the year, on the Tuesday after the clock was returned to standard time, and people got an extra hour’s sleep.

One clear answer: we need 25-hour days.

More details: --
Researchers used Michigan's BMC2 database, which collects data from all non-federal hospitals across the state, to identify admissions for heart attacks requiring percutaneous coronary intervention from Jan. 1, 2010 through Sept. 15, 2013. A total of 42,060 hospital admissions occurring over 1,354 days were included in the analysis. Total daily admissions were adjusted for seasonal and weekday variation, as the rate of heart attacks peaks in the winter and is lowest in the summer and is also greater on Mondays and lower over the weekend. The hospitals included in this study admit an average of 32 patients having a heart attack on any given Monday. But on the Monday immediately after springing ahead there were on average an additional eight heart attacks. There was no difference in the total weekly number of percutaneous coronary interventions performed for either the fall or spring time changes compared to the weeks before and after the time change.
daylight  dst  daylight-savings  time  dates  calendar  science  health  heart-attacks  michigan  hospitals  statistics 
march 2014 by jm
Microsoft's Azure Feb 29th, 2012 outage postmortem
'The leap day bug is that the GA calculated the valid-to date by simply taking the current date and adding one to its year. That meant that any GA that tried to create a transfer certificate on leap day set a valid-to date of February 29, 2013, an invalid date that caused the certificate creation to fail.' This caused cascading failures throughout the fleet. Ouch -- should have been spotted during code review
azure  dev  dates  leap-years  via:fanf  microsoft  outages  post-mortem  analysis  failure 
march 2012 by jm
Web service - current time zone for a city? - Stack Overflow
'a web service of some sort (or any other way) to pull a current time zone settings for a (US) city. For the parts of the country that don't follow the Daylight Saving Time and basically jump timezones when everyone else is switching summer/winter time... I don't fancy creating own database of the places that don't follow DST. Is there a way to pull this data on demand?' seems the closest thing
dst  daylight-savings  local  timezones  iso8601  dates  times  web-services  http  from delicious
october 2010 by jm

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