pike.git / lib / modules / Calendar.pmod / tzdata / Theory

version» Context lines:

pike.git/lib/modules/Calendar.pmod/tzdata/Theory:256:    October 1, Casablanca time, and tomorrow Morocco changes its    daylight saving rules, software can mess up after the rule change    if it blithely relies on conversions made before the change.       * The pre-1970 entries in this database cover only a tiny sliver of how    clocks actually behaved; the vast majority of the necessary    information was lost or never recorded. Thousands more zones would    be needed if the tz database's scope were extended to cover even    just the known or guessed history of standard time; for example,    the current single entry for France would need to split into dozens -  of entries, perhaps hundreds. +  of entries, perhaps hundreds. And in most of the world even this +  approach would be misleading due to widespread disagreement or +  indifference about what times should be observed. In her 2015 book +  "The Global Transformation of Time, 1870-1950", Vanessa Ogle writes +  "Outside of Europe and North America there was no system of time +  zones at all, often not even a stable landscape of mean times, +  prior to the middle decades of the twentieth century". See: +  Timothy Shenk, Booked: A Global History of Time. Dissent 2015-12-17 +  https://www.dissentmagazine.org/blog/booked-a-global-history-of-time-vanessa-ogle       * Most of the pre-1970 data entries come from unreliable sources, often    astrology books that lack citations and whose compilers evidently    invented entries when the true facts were unknown, without    reporting which entries were known and which were invented.    These books often contradict each other or give implausible entries,    and on the rare occasions when they are checked they are    typically found to be incorrect.       * For the UK the tz database relies on years of first-class work done by