Y2K38

The Y2K38 problem, also known as the Year 2038 problem or the Millennium Bug II, is a potential issue with computer systems that could arise on January 19, 2038, at 03:14:07 UTC. This problem stems from the way many systems store dates and times.

Many older and even some current computer programs and operating systems use a 32-bit signed integer to represent the number of seconds that have elapsed since the Unix epoch, which is January 1, 1970. A 32-bit signed integer has a maximum value of 2,147,483,647.

On January 19, 2038, at 03:14:07 UTC, the number of seconds since the Unix epoch will exceed this maximum value. When this happens, the time will "roll over" to a negative number, which could cause many systems to malfunction, crash, or behave unpredictably. This is similar to the Y2K problem of 2000, which was caused by systems storing years with only two digits.

The Y2K38 problem affects systems that rely on this specific 32-bit timestamp representation. This includes older versions of Unix and Unix-like operating systems, as well as applications and embedded systems that have not been updated. Common impacts could include incorrect date calculations, scheduling failures, and data corruption.

To mitigate the Y2K38 problem, developers have been encouraged to use 64-bit integers for time representation. A 64-bit signed integer can store seconds until the year 292,277,026,596. Many modern operating systems and programming languages already support 64-bit timestamps. The transition to 64-bit systems is an ongoing process, and it is crucial for all systems relying on timekeeping to be assessed and updated before the Y2K38 deadline.