Leap Second support in computers

Author

Hack, Michel ; Meng, Xiaoqiao ; Froehlich, Steve ; Zhang, Li

Author_Institution

IBM Thomas J. Watson Res. Center, Yorktown Heights, NY, USA

fYear

2010

fDate

Sept. 27 2010-Oct. 1 2010

Firstpage

91

Lastpage

96

Abstract

The seconds-in-epoch method of representing current time in computers presents problems when required to (a) represent UTC, (b) be monotonic and (c) have sub-second accuracy, as these are contradictory requirements in the presence of Leap Seconds. We analyze various proposed solutions to this conundrum, for both operating systems and NTP. (What good is microsecond-level clock synchronization if the clock can be off by a full second?) We then propose a general solution: TAI-based system time, with conversion to UTC by comparing to a TAI-based threshold and then subtracting the appropriate Leap Second Offset.

Keywords

clocks; computers; measurement standards; synchronisation; NTP; TAI-based system time; UTC; computers; leap second offset; leap second support; microsecond-level clock synchronization; operating systems; seconds-in-epoch method; Clocks; Computers; Linux; NIST; Operating systems; Servers; Synchronization; Leap Second; NTP; TAI; UTC; gettimeofday;

fLanguage

English

Publisher

ieee

Conference_Titel

Precision Clock Synchronization for Measurement Control and Communication (ISPCS), 2010 International IEEE Symposium on

Conference_Location

Portsmouth, NH

Print_ISBN

978-1-4244-5978-0

Type

conf

DOI

10.1109/ISPCS.2010.5609776

Filename

5609776