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Don’t believe everything you learn - PHPSouthCoast

Don’t believe everything you learn - PHPSouthCoast

A minute always has 60 seconds, right? Wrong! Ok, but a country always has a capital city, right? Wrong again!

Come and join us for a lighthearted talk about some of the common falsehoods that developers believe which cause issues in real, production systems. We’ll cover the classics like timezones and names, as well as some new contenders such as geography and software versions.

Michael Heap

June 09, 2017
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  1. @mheap The number of days in every month starts with

    a 3, so either 30 or 31? February has 28
  2. #phpsc17 Each month always has the same number of days

    every year though? February has 29 in leap years
  3. #phpsc17 But we can calculate leap years. They’re every four

    years (Unless it’s divisible by 100) If it divides by 100 and 400, it is a leap year
  4. #phpsc17 February is 28 or 29 days February the 30th

    doesn’t exist Unless you’re Sweden
  5. #phpsc17 February is 28 or 29 days February the 30th

    doesn’t exist Or the Soviet Union
  6. #phpsc17 The offsets between two timezones will always be the

    same 10 changes in 2016 2 changes so far in 2017
  7. @mheap Timezones are always +/- an integer number of hours

    Afghanistan, +04:30 New Zealand (Chatham Islands), +12:45
  8. @mheap If they do change, there’ll be plenty of notice

    North Korea, 2015 8 days notice of a 30 minute change
  9. @mheap There are always 24 hours in a day Daylight

    Savings Time Means 23 or 25 hours in a day
  10. @mheap A child will have the same surname as either

    their mother or father (or both)
  11. @mheap A child will have the same surname as either

    their mother or father (or both) Not in Iceland
  12. #phpsc17 People have at least 2 names Teller (of Penn

    & Teller fame) Akihito (Emperor of Japan)
  13. @mheap I can safely assume that this list of bad

    words has no names in it Ever been to Middlesex?
  14. @mheap I can safely assume that this list of bad

    words has no names in it Eaten shittake mushrooms?
  15. @mheap I can safely assume that this list of bad

    words has no names in it Been named Craig Cockburn?
  16. @mheap I can safely assume that this list of bad

    words has no names in it Linda Callahan?
  17. #phpsc17 If the addresses on the left are even, addresses

    on the right must be odd Seine-Saint-Denis, France Even numbers on both sides, no odds
  18. @mheap You can omit leading zeros 101 Alma St, Palo

    Alto Apartments 1 and 001 on different floors.
  19. #phpsc17 A street name won't include a number 8 Seven

    Gardens Burgh, Woodbridge, IP13 6SU
  20. #phpsc17 You can’t have two towns/cities with the same name

    in a country The UK has three places named Newport
  21. @mheap Those cities don’t have duplicate street names 10 High

    Street, Newport, PO30 1SS 10 High Street, Newport, NP20 1FQ 10 High Street, Newport, TF10 7AN
  22. #phpsc17 Street names will be reasonably short Aleja Alije Izetbegovića

    Prvig Predsjednika Predsjedništva Republika Bosna i Hercegovina
  23. @mheap A building has a single postcode DVLA Swansea: V5Cs

    are processed at SA99 1BA, Driving licences at SA99 1AB
  24. @mheap Concrete buildings are a fixed point in space In

    Zürich, a 6200 ton building was moved by 60 meters to make way for railway tracks
  25. #phpsc17 Do all countries have a capital city? Switzerland does

    not. The government is currently in Bern, but the city is not the capital
  26. #phpsc17 A product has one price Price with tax, price

    without tax, sale price, list price, minimum price
  27. @mheap A product has a price Products sold on auction

    sites do not have a price until it’s sold
  28. @mheap Currencies have a unicode symbol that represents them The

    Swiss franc does not Until 2010, neither did the Indian rupee
  29. The network is reliable. Latency is zero. Bandwidth is infinite.

    The network is secure. Topology doesn't change. There is one administrator. Transport cost is zero. The network is homogeneous.
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