Question

What is the difference between User Threads and Kernel Threads? Name 2 advantages and 2 disadvantages for each threading model.

Answer 1

------difference between user thread and kernel thread------------------

1-> User thread-- These thread are supported above the kernel and are implemented by a thread library at the user level.

Kernel thread-- these are directly supported by operating system.

2-> User thread-- these are generic and can run on any os.

Kernel thread-- these are specific to the os.

3-> User thread--each process needs its own private thread table to keep track of the thread in that process.

Kernel process-- Kernel has a thread table that keep track of all the threads in the system.

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ADVANTAGE OF USER THREAD--

1- THESE ARE EASIER AND FASTER THAN KERNEL THREAD.

2- THESE CAN BE RUN ON ANY OPERATING SYSTEM.

DISADVANTAGE OF USER THREAD--

1-ENTIRE PROCESS WILL BE BLOCKED IF ONE USER LEVEL THREAD PERFORM BLOCKING OPERATION.

2-MULTI THREADED APPLICATION IN USER LEVEL THREAD CAN NOT USE MULTIPROCESSING TO THEIR ADVANTAGE.

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ADVANTAGE OF KERNEL THREAD--

1-THE KERNEL ROUTINES CAN BE MULTI THREADED.

2-OTHER THREADS WILL NOT BE AFFECTED IF ONE THREAD PERFORM BLOCKING OPERATION.

DISADVANTAGE OF KERNEL THREAD--

1-THESE ARE SLOWER TO CREATE AS WELL AS MANAGE AS COMPARE TO USER LEVEL THREADS.

2-A MODE SWITCH TO KERNEL MODE IS REQUIRED TO TRANSFORM CONTROL TO ONE THREAD TO ANOTHER IN A PROCESS.