crash recovery in log file, any idea?????

Hello,
I was looking through my log files and I saw that at some places, it says that crash recovery completed.
Can any body explain to me why crash recovery completed has been appearing in my log file?

thanks,
dorothy

because the database was not shutdown properly, therefore it caused an instance failure. An instance failure is recovered by Oracle automatically and it's written in alert file as crash recovery.

But, tell me why the instance has to crash every now and then, is there any way to see what was the problem. I do hv the same error on my log files. How do i sort that out?

well instance failure = shutdown abort and shutdown abort = power failure, machine not properly shutdown, in Win NT/2K I have faced situations that when I reboot the machine the database was always shutdown with abort option