What has throwing exceptions got to do with kernel vs user mode? Switching to kernel mode is done by a “trap” call (wich is strictly speaking an interupt that is handled by a kernel process/thread), using the terminology I was thaught in “Operating Systems” at school. A runtime exception in a highlevel language may be a trap call or an interrupt handled by some error handling code in the OS or interpreter when trying to read/write to protected memory etc. but an “exception” doesn’t need to involve kernel traps (I think)…