Year 2040[edit]
Early Apple Macintosh computers store time in their real-time clocks (RTCs) and HFS filesystems as an unsigned 32-bit number of seconds since 00:00:00 on 1 January 1904. After 06:28:15 on 6 February 2040 (i.e. 232-1 seconds from the epoch), this will wrap around to 1904: [33] further to this, HFS+, the default format for all of Apple's recent Macintosh computers, is also affected. The replacement Apple File System resolves this issue.
ProDOS for the Apple II computers only supports two-digit year numbers. To avoid Y2K issues, Apple issued a technical note stating that the year number was to represent 1940-2039.[34] Software for the platform may incorrectly display dates beginning in 2040, though a third-party effort is underway to update ProDOS and application software to support years up to 4095.[35]
Year 2028[edit]
During the late 1970s, on Data General Nova and Eclipse systems, the World Computer Corporation (doing credit union applications) created a date format with a 16-bit date field for 128 years (7 bits - note 1900+128=2028), 12 months (4 bits) and 31 days (5 bits).
This allowed dates to be directly comparable using unsigned functions. No known instances of this format are in use today.
Classic Mac OS[edit]
The control panel in Classic Mac OS versions 6, 7, and 8 only allows the date to be set as high as 31 December 2019, although the system is able to continue to advance time beyond that date.[24][25]
9/9/99[edit]
In many programs or data sets, "9/9/99" was used as a rogue value to indicate either an unresolved date or as a terminator to indicate no further data was in the set. This raised issues upon the arrival of the actual date this represents, 9 September 1999.[5]
Two-digit year representations[edit]
Follow-on problems caused by certain temporary fixes to the Y2K problem will crop up at various points in the 21st century. Some programs were made Y2K-compliant by continuing to use two digit years, but picking an arbitrary year prior to which those years are interpreted as 20xx, and after which are interpreted as 19xx.[7]
For example, a program may have been changed so that it treats two-digit year values 00–68 as referring to 2000 through 2068, and values 69–99 as referring to 1969 through 1999.[8] Such a program will not be able to correctly deal with years beyond 2068.
For applications required to calculate the birth year (or another past year), such an algorithm has long been used to overcome the Year 1900 problem, but it has failed to recognise people over 100 years old.
Year 2011[edit]
Taiwan officially uses the Minguo calendar, which considers the Gregorian year 1912 to be its year 1. Thus, the Gregorian year 2011 is the ROC year 100, its first 3-digit year.[15]
Year 2036[edit]
The Network Time Protocol has an overflow issue related to the Year 2038 problem, which manifests itself at 06:28:16 UTC on 7 February 2036, rather than 2038. The 64-bit timestamps used by NTP consist of a 32-bit part for seconds and a 32-bit part for fractional second, giving NTP a time scale that rolls over every 232 seconds (136 years) and a theoretical resolution of 2−32 second (233 picoseconds). NTP uses an epoch of 1 January 1900. The first rollover occurs in 2036, prior to the UNIX year 2038 problem.[31][32]
Year 10,000[edit]
The year 10,000 will be the first Gregorian year with five digits. Although many people at first consider this year to be so far distant that a problem of this type will never actually occur, certain classes of calculations in disciplines such as astronomy and physics already need to work with years of this magnitude and greater. These applications also have to deal with the Year zero problem. All future years that are powers of 10 have the potential for similar problems.
"RFC 2550 - Y10K and Beyond"[49] discusses solutions for dealing with this problem.
https://en.wikipedia.org/wiki/Time_formatting_and_storage_bugs#Year_10,000
https://en.wikipedia.org/w/index.php?title=Year_10,000_problem&redirect=no
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