Consider the following statements about user level threads and kernel ...
Kernel level threads are managed by the OS, therefore, thread operations are implemented in the kernel code. Kernel level threads can also utilize multiprocessor systems by splitting threads on different processors. If one thread blocks it does not cause the entire process to block. Kernel level threads have disadvantages as well. They are slower than user level threads due to the management overhead. Kernel level context switch involves more steps than just saving some registers. Finally, they are not portable because the implementation is operating system dependent.
Option (A): Context switch time is longer for kernel level threads than for user level threads. True, As User level threads are managed by user and Kernel level threads are managed by OS. There are many overheads involved in Kernel level thread management, which are not present in User level thread management. So context switch time is longer for kernel level threads than for user level threads.
Option (B): User level threads do not need any hardware support True, as User level threads are managed by user and implemented by Libraries, User level threads do not need any hardware support.
Option (C): Related kernel level threads can be scheduled on different processors in a multi- processor system. This is true.
Option (D): Blocking one kernel level thread blocks all related threads. false, since kernel level threads are managed by operating system, if one thread blocks, it does not cause all threads or entire process to block.
View all questions of this test
Consider the following statements about user level threads and kernel ...
Explanation:
User level threads and kernel level threads are two types of threads used in operating systems. The following statements provide some characteristics of these threads:
a) Context switch time is longer for kernel level threads than for user level threads.
- When a context switch occurs, the current state of the running process or thread is saved, and the state of the next process or thread to be executed is restored. Context switch time refers to the time it takes to perform these operations.
- For kernel level threads, the context switch involves switching between user mode and kernel mode, which requires more overhead than switching between user level threads.
- Therefore, the statement is true.
b) User level threads do not need any hardware support.
- User level threads are implemented entirely in user space, without any direct support from the operating system kernel.
- Therefore, the statement is true.
c) Related kernel level threads can be scheduled on different processors in a multi-processor system.
- In a multi-processor system, the operating system can schedule kernel level threads on different processors to take advantage of parallelism.
- Therefore, the statement is true.
d) Blocking one kernel level thread blocks all related threads.
- Kernel level threads belong to the same process and share the same address space and resources.
- If a kernel level thread is blocked, it may cause other threads in the same process to block as well, depending on how the resources are managed.
- However, blocking one kernel level thread does not necessarily block all related threads.
- Therefore, the statement is false.
Conclusion:
The false statement about user level threads and kernel level threads is that blocking one kernel level thread blocks all related threads.
To make sure you are not studying endlessly, EduRev has designed Computer Science Engineering (CSE) study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Computer Science Engineering (CSE).