Maximum uptime 497 days?

[Oliver Fromme]

Rob <stopspam at users.sourceforge.net> wrote:
 > By accident I happen to come across this remarkable limit of
 > uptime registration for FreeBSD systems. After 497 days, the
 > timer jumps to zero again.
 > 
 > 497 days is less than a 1.5 years !

I'd be very embarrassed to have machines with that a high
uptime -- It means that they haven't been updated for that
a long time and are probably full of security holes.  ;-)

 > Has this been fixed in newer versions of FreeBSD (stable and/or
 > current) ? Or is there a hardware limitation (CPU?) that does
 > not allow this?

I'm pretty certain I have seen FreeBSD machines with more
that 497 days of uptime.  The boot time is stored as a
struct timeval in sysctl kern.boottime, which is enough for
several decades.

Which program did you use to display the uptime?  It's pro-
bably a bug in that program, not in freeBSD.

I guess that that program calculates the uptime with 1/100s
precision and stores it in a 32bit int.  That would explain
the 497 days limit:  2^32 / 24 / 60 / 60 / 100 == 497.1.

Best regards
   Oliver

-- 
Oliver Fromme, secnetix GmbH & Co KG, Oettingenstr. 2, 80538 München
Any opinions expressed in this message may be personal to the author
and may not necessarily reflect the opinions of secnetix in any way.

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