6- I/O subsystem is not responsible for: a) Drivers b) Device Drivers c) Memory management d) Data modification on a disk 7- A system call: a) Is executed in user mode b) Is executed in kernel mode c) Is executed in a tertiary mode d) Is executed in any mode 8- A trap is not raised when: a) A division by zero occurs b) An invalid memory access is done c) An I/O device finishes an I/O operation d) A kernel routine is invoked