What is the purpose of the mode bit provided by CPU hardware?
Correct answer B. It indicates whether the CPU is executing in kernel mode or user mode
Explanation
Dual-mode operation uses a hardware mode bit to tell whether the current instruction runs on behalf of the operating system (kernel mode) or a user program (user mode). Privileged instructions are allowed only in kernel mode, which protects the OS from faulty or malicious programs. The sign flag records negative results, and the dirty bit belongs to page-table entries, not the mode bit.
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