Incohérence entre commandes uptime et who -b

OK, je vais essayer
Merci pour ton aide dubcek

je supposerais une incohérence dans le fichier var/run/utmp , le recréer, à moins que cela se fasse automatiquement, au prochain reboot.

who -b /var/log/utmp ne me retourne rien

[root@server root]# who -b /var/run/utmp
system boot Apr 12 17:58

[root@server root]# who -b /var/log/utmp
[root@server root]#

il n'y a que who qui est incohérent, y a-t-il une différence:
who -b /var/run/utmp
who -b /var/log/wtmp

[root@server init.d]# w
14:59:44 up 31 days, 18:23, 2 users, load average: 0.06, 0.08, 0.05
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
btech pts/1 10.173.207.2 Mon 9am 2days 0.00s 0.00s -ksh
root pts/3 10.173.207.2 9:34am 0.00s 0.11s 0.01s w

[root@server init.d]# top -b|head

14:59:13 up 31 days, 18:23, 2 users, load average: 0.10, 0.09, 0.05
137 processes: 136 sleeping, 1 running, 0 zombie, 0 stopped
CPU states: cpu user nice system irq softirq iowait idle
total 1.6% 0.0% 0.0% 0.0% 0.0% 0.0% 398.0%
cpu00 0.9% 0.0% 0.0% 0.0% 0.0% 0.0% 99.0%
cpu01 0.9% 0.0% 0.0% 0.0% 0.0% 0.0% 99.0%
cpu02 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 100.0%
cpu03 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 100.0%

[root@server init.d]# last
root pts/3 10.173.207.2 Wed Sep 23 09:34 still logged in
btech pts/1 10.173.207.2 Mon Sep 21 09:15 still logged in
btech pts/3 10.173.207.2 Wed Sep 16 17:02 - 17:34 (00:32)
btech pts/1 10.173.207.2 Wed Sep 16 16:51 - 17:35 (00:43)
btech pts/1 10.173.207.2 Tue Sep 15 10:57 - 10:59 (00:01)

hello
est les commandes last, top -b|head -1 et w , quelles dates retournent-elles ?