[讨论]怎么给我改的日志？？

[core]

（FC4系统 ）本人习惯用root用户和dwei用户，可是看看11日，
没有开机的日志，叫人齐刷刷的给抹了啊，
到底怎么给改的？？？
盼高手给解释下啊！！
dwei tty4 Sun Nov 11 14:35 - 14:35 (00:00)
dwei pts/2 :0.0 Sat Nov 10 16:38 - down (01:04)
dwei pts/1 :0.0 Sat Nov 10 15:50 - down (01:52)
dwei pts/1 :0.0 Sat Nov 10 15:48 - 15:50 (00:01)
dwei :0 Sat Nov 10 15:48 - down (01:54)
root pts/3 Sat Nov 10 13:25 - 14:18 (00:53)
root pts/2 Sat Nov 10 13:25 - 15:48 (02:23)
root pts/1 Sat Nov 10 13:24 - 15:48 (02:23)
root :0 Sat Nov 10 13:24 - 15:48 (02:23)
reboot system boot 2.6.17-1.2142_FC Sat Nov 10 13:24 (04:18)
root pts/4 Fri Nov 9 10:45 - 10:53 (00:07)
root pts/3 Fri Nov 9 09:20 - 11:25 (02:05)
root pts/2 Fri Nov 9 09:20 - down (07:56)
root pts/1 Fri Nov 9 09:19 - down (07:56)
root :0 Fri Nov 9 09:19 - down (07:56)