Driver close system call

[Wm. Tseng]

I have a question about driver close routine. Thanks in advance for any answer.

  If a process exits or terminates before it closes a driver, does kernel close
the driver for that process ? In user process, several processes can open the 
same driver. Are driver open and close routines executed as many time as process
calls it ? Does kernel control the close system call, so close is only executed
once (when last process closes it)? When system crash, does kernel close all 
the opened file and driver or just leave them open ?

					william
					williamt at babel.sandiego.ncr.com