Which of the following instructions should be allowed only in kernel mode? (a) Disable all interrupts. (b) Read the time-of-day clock. (c) Set the time-of-day clock. (d) Change the memory map.

A, B and D

Explanation:

The kernel is the central core of the computer's operating system, that has total control of all the activities of the computer. The kernel is a very small program in memory and runs first during the boot of the system. It is the interactive link between the hardware and operating system and other system softwares.

The uses a command line to receive and execute command for various system configurations like storage and memory mapping, enable and disable interrupts, set timers or allocate time slice to run programs etc.