Re: [tlug] Re: [OT] Intel core duo errata

[Darren Cook <darren@example.com>]

>> For why see: http://uptime.netcraft.com/up/accuracy.html#cycle
>> (linux is one of the OSes that never show an uptime above 497 
>> days; linux 2.6 apparently never goes above 49 days.)
> 
> Has anyone heard of ANY operating system having this issue?

My question was how on earth can someone from the outside know my
uptime???!! It's not like apache returns it as a header, and I don't
have "uptime-server" running :-).

I fuzzily understood it as follows: it is something about TCP/IP headers
using the time-since-boot as a unique id. Some OSes use the whole time,
but linux only uses the low bits of the time. So if a machine has been
up 500 days it shows (to the external world, via the TCP/IP headers) as
only having been up for 3 days. Linux 2.6 uses even fewer bits so wraps
after 49 days.

Darren