Webopedia on Google+Webopedia on TwitterWebopedia on FacebookTech Bytes Blog
Main » TERM » L »

leap second

A leap second refers to the periodical addition of one second to the Coordinated Universal Time (UTC) in order to keep clocks throughout the world synchronized with the Earth's ever-slowing rotation.

By adding a leap second when the UTC drifts 0.9 seconds from the Universal Time (UT1), or Astronomical Time, clocks that are synched with UTC effectively stop for one second to allow "the Earth the opportunity to catch up with atomic time," according to timeanddate.com.

Leap seconds are announced and coordinated by the International Earth Rotation and Reference System Service (IERS) in Paris, France. Twenty-six leap seconds have been recorded, with the first taking place in 1972.

The most recent leap second took place on Saturday, December 31st, 2016, at 6:59:60pm, and the next is expected to occur sometime in 2018.

Why Leap Seconds Can Be Problematic for IT

Leap seconds can be problematic for IT systems and software code, particularly applications and services that require time synchronization with other systems in order to run smoothly.

Systems with code that hasn't accounted for leap seconds can appear to be sending information from the future when attempting to sync with applications that have adjusted for the leap second. This can result in errors with tracking and reporting events, keeping replications up to date and in sync, determining the order of data operations, and more.

Google's Leap Smear Available to Account for 2016 Leap Second

Google relies on a technique known as "smeared time," or a leap smear, to avoid potential critical issues associated with leap seconds. For the 2016 Leap Second, Google announced it would let anyone use its NTP (Network Time Protocol) servers to help avoid issues.

Google's NTP servers run clocks 0.0014 percent slower for 10 hours before the leap second and then do the same for 10 hours afterward to account for a leap second without disrupting applications and systems that depend on time synchronization.

Google's NTP servers are freely available through the Google Public NTP service. By configuring network settings to utilize time.google.com as their NTP server, enterprises can ensure their systems and apps will be able to handle leap seconds. Google offers detailed instructions for utilizing leap smears for synchronizing systems.







TECH RESOURCES FROM OUR PARTNERS
LATEST ARTICLES
SEO Dictionary

From keyword analysis to backlinks and Google search engine algorithm updates, our search engine optimization glossary lists 85 SEO terms you need... Read More »

Slideshow: History of Microsoft Operating Systems

Microsoft Windows is a family of operating systems for personal computers. In this article we look at the history of Microsoft operating... Read More »

Slideshow: Interesting Facts About Google Search

From Goats to Penguins, a server outage and trillions of searches, our slideshow presents interesting facts about Google and the Google.com... Read More »

STUDY GUIDES
Java Basics, Part 1

Java is a high-level programming language. This guide describes the basics of Java, providing an overview of syntax, variables, data types and... Read More »

Java Basics, Part 2

This second Study Guide describes the basics of Java, providing an overview of operators, modifiers and control Structures. Read More »

The 7 Layers of the OSI Model

The Open System Interconnection (OSI) model defines a networking framework to implement protocols in seven layers. Use this handy guide to compare... Read More »

?>