The Configuration Change Notification and Logging feature is supposed to log changes to the router's configuration. While it does a great job of logging commands entered in the router configuration mode, it completely ignores configuration changes due to configuration download (for example, with configure network or copy tftp running-config command). Here is an example:

fw#configure terminal
fw(config)#archive
fw(config-archive)#log config
fw(config-archive-log-cfg)#logging enable
fw(config-archive-log-cfg)#^Z
fw#
fw#configure network
Host or network configuration file [host]?
This command has been replaced by the command:
         'copy  system:/running-config'
Address or name of remote host [10.0.0.2]?
Source filename [fw-confg]?
Configure using tftp://10.0.0.2/fw-confg? [confirm]
Loading fw-confg from 10.0.0.2 (via FastEthernet0/0): !
[OK - 858 bytes]
fw#
%SYS-5-CONFIG_I: Configured from tftp://10.0.0.2/fw-confg by console
fw#show archive log config all
 idx   sess           user@line      Logged command
    1     1        console@console    logging enable