Computer Time

So how does you computer know what time it is? Cory Doctorow at Boing Boing points out the tz database.

At a recent meeting of the CalConnect calendaring consortium I was astounded to learn that there is no official body that tracks timezone data around the world. The best information is in the tz database which is maintained, as I understand it, on a completely voluntary basis by Arthur David Olson, a systems administrator at NIH, for whom this is not even his regular day job. This database is apparently the basis used by almost all operating systems and software around the world to keep track of timezone information. And there are some wacky things to keep track of - for instance, Myanmar is +6.5 hours from UTC, and Nepal is +5:45 hours!

The GNU C Library used in GNU/Linux, FreeBSD, NetBSD, OpenBSD, Cygwin, DJGPP, HP-UX, IRIX, Mac OS X, OpenVMS, Solaris, Tru64, and UnixWare all use the tz database.

Windows has it own time service.