Windows Server 2019 and Windows 10 become the first OS with leap seconds’ support

Windows Server 2019 and Windows 10 will become the first ever operating systems to be extending support for leap seconds, Microsoft today revealed. The next Windows update which is scheduled for fall came after international governmental regulations from US and EU (FINRA, ESMA/MiFDII) demand higher accuracy in time as strict as 100 microseconds.

The leap second concept was widely known for several years, however until yet Microsoft did not intend to work on it. Now, owing to the international regulations, the company had no choice but to focus on this issue.

According to Microsoft’s Networking Blog by Dan Cuomo, “…we first brought 1 ms (millisecond) time accuracy to Windows Server 2016 meeting some of the regulatory requirements – This is supported in-market today.  However, our work was not done, and so Windows Server 2019 makes improvements to comply with these regulations and allow Windows to be the preferred choice for workloads with time dependencies.”

Although, leap second support does not mean much for the users, it still remains a big deal for the software giant. A leap-second refers to the occasional one-second adjustment to UTC. This adjustment is important because as the earth’s rotation is slowed down, UTC diverges from the astronomical time. Once it gets diverged, leap second insertion allows for keeping UTC in-sync with the mean solar time. The leap second typically occurs once every eighteen months. Now, Microsoft has decided to improve this inherent accuracy in their platforms.

Before this update, Windows clock did not count leap seconds and used to jump directly from 16:59:59 to 17:00:00. After this recent update, the clock will go from 16:59:59 to 16:59:60 and then 17:00:00. The following GIF shows how the Microsoft clock will now add a leap second.

Microsoft Tech Blog

The extra second concept will be a part of Precision Time Control as well which is one of the several other improvements and updates included in Windows Server 2019. The rest of the details can be viewed on Microsoft’s tech blog.

Maira Ahmed

Maira is a system analyst for the last 10 years. She likes to explore, experience and understand new technologies shaping the future. She was a key member of the MUM "Mera Urdu Messenger"s (R&D) team, the first ever Urdu messenger released by CRI in the 90s.