BCS1333 OS: Exercise Chapter 4 (Threads)

[aktiviti untuk 17 mac. sila jawap soalan 1 hingga 4)
The process model introduced in Chapter 3 assumed that a process was an
executing program with a single thread of control. Many modern operating
systems now provide features for a process to contain multiple threads of
control.

1. What is threads?
2. What is multi threading?
3. Explain four benefits of multi threading.
4. Briefly describe (or sketch)  Multi Threading Model available (many-to-one,one-two-one and many-to-many)

5. Provide one programming examples in which multi threading does not
provide better performance than a single-threaded solution
Answer:  Any kind of sequential program is not a good candidate
to be threaded. An example of this is a program that calculates an individual
tax return.

6. Consider a multiprocessor system and a multi threaded program written
using the many-to-many threading model. Let the number of user-level
threads in the program be more than the number of processors in the
system.Discuss the performance implications of the following scenarios.
a. The number of kernel threads allocated to the program is less than
the number of processors.
b. The number of kernel threads allocated to the program is equal
to the number of processors.
c. The number of kernel threads allocated to the program is greater
than the number of processors but less than the number of user level
threads.