![]() ![]() ![]() Thus a BCD 10 16 interpreted as a hexadecimal encoding erroneously represents the decimal number 16.įor example, the SMS protocol uses BCD encoding for dates, so some mobile phone software incorrectly reported dates of messages as 2016 instead of 2010. But the decimal number 10 is encoded in hexadecimal as 0A 16 and in BCD as 10 16. The numbers 0 through 9 are encoded in both hexadecimal and BCD as 00 16 through 09 16. The main source of problems was confusion between hexadecimal number encoding and BCD encodings of numbers. This was dubbed by some in the media as the "Y2K+10" or "Y2.01k" problem. Some systems had problems once the year rolled over to 2010. On, the Motorola 68000 again does not divide due to overflow protection, which the Mac SCI ignores. Programs with the MCDATE patch freeze because the Mac SCI takes the current number of seconds since the Macintosh epoch of 1 January 1904, subtracts 432,000,000 seconds from that, and then divides by 12 hours through the Motorola 68000, to then determine how long delays should last. As with the #Year 1993 program, this was due to an issue in the Mac SCI when attempting to use the date to determine how long a delay should last. Sierra Entertainment games for the Classic Mac OS that were patched with the MCDATE program or released afterwards with the patch built in would begin to freeze on. Systems that used a string of nine digits to record the time as seconds since the Unix epoch had issues reporting times beyond the one-billionth second after the epoch on 9 September 2001 at 01:46:40 (the "billenium"). Such a program will not be able to correctly deal with years beyond 2068.įor 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. įor 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. 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 20 xx, and after which are interpreted as 19 xx. In the last few months before the year 2000, two other date-related milestones occurred that received less publicity than the then-impending Y2K problem.įollow-on problems caused by certain temporary fixes to the Y2K problem will crop up at various points in the 21st century. The Domain/OS clock, which is based on the number of 4-microsecond units that has occurred since 1 January 1980, rolled past 47 bits on 2 November 1997, rendering unpatched systems unusable. Sierra released a patch called MCDATE that resolved the problem for almost 14 years. The division was processed by the Motorola 68000 and would not occur if an overflow was detected because of the division, but the Mac SCI would continue on regardless as if the division had occurred, eventually resulting in a delay of one second being treated as a delay for 18 hours and so on. Mac SCI would attempt to use the date to determine how long a delay should last by getting the current time in seconds since 1 January 1904, the Macintosh epoch, and dividing by 12 hours. An issue in the Mac version of Sierra's Creative Interpreter (Mac SCI) would cause the game to "lock-up" when attempting to handle a delay due to a problem involving an overflow. Multiple Sierra Entertainment games released for the Classic Mac OS started to freeze when running on 18 September 1993. Values on and after this day do not fit into a signed 16-bit integer, but overflow and return negative values. On 18 September 1989, these programs began to fail, the date being exactly 32,768 (2 15) days since the zero date. Some mainframe programs were written to encode dates as the number of days since a 'zero date' of 1 January 1900, storing them as signed 16-bit binary integers. This was recognized when the later COS-310 operating system was developed, and dates were recorded differently. The Digital Equipment Corporation OS/8 operating system for the PDP-8 computer used only three bits for the year, representing the years 1970 to 1977. There were numerous problems and crashes related to this bug while an alternative format was developed. On 4 January 1975, the 12-bit field that had been used for dates in the DECsystem-10 operating systems overflowed.
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