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. 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. The most well-known consequence of bugs of this type is the Y2K problem, but many other milestone dates or times exist that have caused or will cause problems depending on various programming deficiencies.
These are most commonly manifestations of arithmetic overflow, but can also be the result of other issues. In computer science, time formatting and storage bugs are a class of software bugs that cause errors in time and date calculation or display.
0 kommentar(er)
