Time waits for no one: 'leap seconds' may be cut

Problematic for computers, the leap second may be banished

By Joab Jackson, IDG News Service |  Networking

Sparking a fresh round of debate over an ongoing issue in time-keeping circles, the International Telecommunications Union is considering eliminating leap seconds from the time scale used by most computer systems, Coordinated Universal Time (UTC).

Since their introduction in 1971, leap seconds have proved problematic for at least a few software programs. The leap second added on to the end of 2008, for instance, caused Oracle cluster software to reboot unexpectedly in some cases.

Some computer professionals argue, however, that abolishing the leap second at this point will just cause another set of difficulties. The revision "would cause more trouble than it naively claims to circumvent," wrote programmer Rob Seaman, on the Leap Seconds mailing list.

ITU's Radiocommunication Sector (ITU-R), which oversees UTC, is seeking input through October on a potentially revised definition of UTC that does not include leap seconds, an idea that has been under consideration for the past decade. If this working group approves the recommendation, it could go before the next ITU Radiocommunications Assembly in 2012 for final approval, and be implemented by 2018.

The leap second came about as a way to reconcile the growing difference between how computers and humans keep time.

UTC is defined by an iteration of seconds, which are defined with great precision by atomic clocks. Universal Time, in contrast, measures the day by the time it takes the Earth to do one complete rotation, which can fluctuate slightly due to tidal effects. Since 1971, 24 leap seconds have been added on to UTC in order to reconcile UTC and Universal Time.

In the revised ITU plan, the divergence between UTC and UT will be allowed to grow over the next few hundred years, and could be reconciled by a single leap hour at some point.

Most computer systems use UTC, including all those that rely on the Network Time Protocol (NTP). The problem, researchers note, is that leap seconds aren't handled in any sort of standardized way.

Join us:
Facebook

Twitter

Pinterest

Tumblr

LinkedIn

Google+

Answers - Powered by ITworld

ITworld Answers helps you solve problems and share expertise. Ask a question or take a crack at answering the new questions below.

Join us:
Facebook

Twitter

Pinterest

Tumblr

LinkedIn

Google+

Ask a Question
randomness