April 18, 2014

Y2K and Linux - page 2

In the Beginning...

  • January 1, 1999
  • By Lou Grinzo
The good news is that by and large, Linux and all other members of the Unix family tree are immune to the Y2K problem, since they keep track of time internally in way that's different from that described above. Instead of storing a month, a day, and a year as separate pieces of information, they simply keep a count of the seconds since January 1, 1970, and convert this to a more user-friendly format, as needed...such as when displaying the date a file was last changed. Even better is the news that the vast majority of Linux programs use this same method for representing dates, probably because it was easiest to simply follow the operating system's lead, so they'll also breeze right past 1/1/2000 with nary a hiccup.

This doesn't mean, however, that Linux doesn't have its own data issues. Because that counter Linux uses to store the number of seconds since 1/1/1970 can only hold a number so large (it's a 32-bit binary number, in fact), it will hit its upper limit and wrap around, much like the odometer on a car will go from all 9's to all 0's. This won't happen on Linux and other Unix variants until January of 2038, so we all have considerable breathing room. More important, long before 2038 we will have moved well beyond today's 32-bit systems, and Linux will very likely be changed to use a larger number to store that count of seconds. The next likely size is 64 bits, which will give us a counter so absurdly large it won't wrap around until sometime after the sun burns out.

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