Editing 376: Bug
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==Explanation== | ==Explanation== | ||
β | In computer systems, time is measured starting from some arbitrarily chosen point. That particular time is known as the "{{w|Unix time|epoch}}" for that system. The {{w|UNIX}} operating system internally uses an epoch of January 1, 1970, and measures the time as a number of seconds from then. Since this was intended only for things internal to the OS (File last modified times and the like), using 1-Jan-1970 was safe | + | In computer systems, time is measured starting from some arbitrarily chosen point. That particular time is known as the "{{w|Unix time|epoch}}" for that system. The {{w|UNIX}} operating system internally uses an epoch of January 1, 1970, and measures the time as a number of seconds from then. Since this was intended only for things internal to the OS (File last modified times and the like), using 1-Jan-1970 was safe as no UNIX systems existed before that date. |
However, since UNIX included a number of system functions to manipulate these dates, some developers mistook them for a general purpose date object, and misused them in applications requiring dates before the epoch, by using negative values. Such usage would inevitably fail; for example, since the value isn't specified to be signed or unsigned, the date might be considered to be far in the future, instead of in the past. | However, since UNIX included a number of system functions to manipulate these dates, some developers mistook them for a general purpose date object, and misused them in applications requiring dates before the epoch, by using negative values. Such usage would inevitably fail; for example, since the value isn't specified to be signed or unsigned, the date might be considered to be far in the future, instead of in the past. |