typically utilize frequent time synchronization via
upstream time servers on the web. According to this
article, "a nasty bug's been uncovered in GPSD that's
going to pop up on October 24, 2021. If left
unpatched, it's going to switch your time to some time
in March 2012, and your system will crash."
what time it is by synchronizing NTP servers with
atomic clocks. NTP is based on a hierarchy of levels,
where each level is assigned a number called the
stratum. Stratum 1 (primary) servers at the lowest
level are directly synchronized to national time
services via satellite, radio, or modem. Stratum 2
(secondary) servers are synchronized to stratum 1
servers and so on. Usually, NTP clients and servers
connect to Stratum 2 servers.
How do stratum
1 servers sync up with clocks? Many of them use GPSD.
This service daemon monitors one or more GPSes for
location, course, velocity, and for our purposes, the
most important element it tracks is time. This code,
which is a mix of a linkable C service library, a C++
wrapper class, and a Python module, has, like all
programs, its fair share of bugs. Recently it was
discovered that a bug in the time rollback (aka "GPS
Week Rollover") sanity checking code scheduled for
November 2038 will instead cause 1,024 to be
subtracted from the October 24, 2021 week number. In
other words, a lot of computers are in for a quick,
sharp visit to March 2002.
So, check your
systems now for this problem. And, if, like most of
us, you're relying on someone upstream from you for
the correct time, check with them to make sure they've
taken care of this forthcoming trouble.
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