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. 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 may cause time and date calculation or display to be improperly handled. Software errors affecting times and dates
0 kommentar(er)
