QUESTION 52 Which of the below is/are the operating-system managed threads that act on the...
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QUESTION 52
Which of the below is/are the operating-system managed threads that act on the core operating system?
I) Kernel – level threads
II) User – level threads
Show answer & explanation
Kernel-level threads are directly managed and scheduled by the operating system kernel, making them true OS-managed threads that act on the core OS. User-level threads, by contrast, are managed by user-space libraries (like pthreads) and are not directly visible to or managed by the kernel—the kernel only knows about the kernel-level thread that hosts them.
Step-by-step Derivation:
Threading models differ in management scope:
Kernel-level threads (I): Created and scheduled directly by the OS kernel. The kernel maintains thread control blocks (TCBs), performs context switching, and manages their lifecycle. These are OS-managed and directly act on the core OS.
User-level threads (II): Implemented by user-space thread libraries (e.g., pthreads, green threads). The kernel is unaware of individual user-level threads; it only sees the single kernel-level thread that multiplexes them. Scheduling is done by the user-level library, not the OS kernel.
Since the question asks which threads are "OS-managed" and "act on the core operating system," only kernel-level threads qualify. User-level threads are application-managed, not OS-managed.
Answer: C) Only (I)