Asterisk service log file

Hi all
I use Asterisk 1.4
My Asterisk service hang sometime a week. Therefore I need to file the log that show how many time that Asterisk service is hang. And the method that Asterisk service is stop
For example, if I log in to Web GUI and stop Asterisk service. Where can I find the log that the Asterisk service is stopped by somebody in web Gui
In addition, where can I adjust the feature, such as disconnect feature (**) with Asterisk 1.4?
I cannot find it out
Thanks for your support … nformation