[ntp:questions] Re: Y2038 bug strikes early

David L. Mills mills at udel.edu
Tue Aug 1 19:40:23 UTC 2006


Marc,

Unix doesn't have to have a 2038 rollover problem, just as NTP doesn't 
have a 2036 rollover problem. Evidence to this assertion has been 
reported in recent messages to this list and the hackers at ntp.org support 
group. It's all in the carefully designed 64-bit twos complement 
calculations that determine the relative date and time, as long as the 
clock is set first within 68 years of the actual calendar date. See 
http://www.eecis.udel.edu/~mills/y2k.html.

Dave

Marc Brett wrote:
> From the latest RISKS Digest:
> 
> 
> Date: Thu, 29 Jun 2006 13:38:25 -0700
> From: Conrad Heiney <conrad at fringehead.org>
> Subject: Y2038 bug strikes early
> 
> Starting on May 12, 2006, many installations of the AOLServer web server
> failed. Not all versions or all configurations failed, but the ones that did
> became unusable. On start, the server would eat virtual memory and then
> terminate with a memory allocation error. Discussion on the mailing list
> revealed the starting date of the problem, indicating that some part of the
> software had a clock issue. On careful inspection it was discovered that
> database threads were a common factor. It was then noted by a perceptive
> person that the servers all failed on or before exactly one billion seconds
> before the end of the Unix epoch in 2038. Many installations had very long
> database timeouts, which caused the software to look ahead and see the End
> of Time. Adjusting the timeouts stopped the crashes.
> 
> The risk of the known clock bug striking 32 years early indicates there may
> be other "pre-problems" lurking in software that will show up long before
> the date we have comfortably set as the deadline.
> 
> The thread discussing the problem and its resolution is here: 
> http://www.mail-archive.com/aolserver@listserv.aol.com/msg09812.html




More information about the questions mailing list