Dear all: I try to pass the content of file,1G, to kernel driver for operation and then return the result back to application. My questions are: 1. The only way I can use is copy_from_user? If so, does it have the size limitation? 2. I don't want my application pending on the I/O and is there any smart way to let the application know when driver finishes its job? appreciate your help, vichy -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ