Linuxtrent: Lo sapevate che linux non sta' su piu' di 497 giorni?
- From: Diaolin (Natali Giuliano) <diaolin@xxxxxxxxxxx>
- To: linuxtrent <linuxtrent@xxxxxxxxxxxxxxxxx>
- Date: Sun, 27 May 2001 18:06:51 +0200
Non e' vero pero'........
c'e' un problemuccio banale banale sul calcolo dei secondi difatti dopo 497
giorni 2 ore 27 minuti e 53 secondi l'orologio di uptime che si basa su
include/linux/kernel.h: long uptime; /* Seconds since boot */
..................
leggetevelo e' un bell'articoletto .....
Diaolin
___________________________________________________________
Hello,
The Linux's uptime is not as good as I expected. My expectations were high
because of all the claims that can be read on the net. But my experience is
that within 498 days the uptime showed returns to zero. Let's have a look at
what I noticed in the daily reports I receive from some systems. One day I
read in such a report :
Fri May 18 18:34:14 CEST 2001
6:34pm up 496 days, 20:45, 0 users, load average: 0.29, 0.06, 0.02
The next day I saw :
Sat May 19 18:34:20 CEST 2001
6:34pm up 18:17, 0 users, load average: 0.28, 0.06, 0.02
I looked at the log files but could not find recent boot messages. My fear
was a hacked box, another kernel for loadable modules installed and an edited
logfile. No reason for this fear as there were not any indications that the
box was hacked but one never knows. Now I did some computations and found
that after about 42.949.680 seconds the uptime returned to zero. To be sure I
checked in /var/log and found :
-rw-r--r-- 1 root root 2545 Jan 7 2000 boot.msg
Reasonable date compared to my computation. Another idea was to look at :
/include/linux/kernel.h: long uptime; /* Seconds since boot */
And that proves that my fear was wrong, this counter is incremented every
0.01 second. The maximum value is 4,294,967,296 which translates to
42,949,673 seconds. To which my original calculated value compares well.
My conclusion : the uptime returns to zero after 497 days, 2 hours, 27
minutes and 53 seconds. And Free Software really helps to find out why
somethings happens. Just as I have explained this week in my lecture at the
Linux 2001 congress.
Disclaimer : this is related to the Linux 2.2.x kernel. However, in the Linux
2.4.x kernel the uptime field is also a long integer so I don't expect other
effects.
Have fun,
Fred
--
Tutti hanno diritto di manifestare liberamente il proprio pensiero
anche se alle volte sarebbe meglio evitare figuracce.....
Diaolin Constitution (art 1)
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