Testbook 4 Qno 32

Question

# i got 2 and 3 is correct. pplz explain  1st ???

Comments

but given all correct

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http://stackoverflow.com/questions/1178785/relationship-between-a-kernel-and-a-user-thread I don't think so. Refer this link and search for the keyword page fault.

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All are correct. Page fault means IO and for IO, when user level thread is requester then entire process is blockd because OS is unaware of the abstraction.

Answer 1

Statement III is correct context switching of kernel level threas are higher then user level thread as user level thread are transparent and have less context compared to kerel level thread

 

Statement II. is also true here page fault is related to when a process blck that is when any of the user level thread get block complete process will get in block state as user level threads are dependent on each other but this is not true in kernel level thread, kernel level thread will still do work correctly

 

Statement I is true itself.

 

All are true

Comments

@Sandeep.

For statement 2: when single user level thread requests I/o, the entire process gets blocked because the OS doesnt know that this is indeed thread and not the process. OS thinks that this is request from process and hence, blocks the process.

Plz make it appropriate.

Your answer is correct.