as requested and identifies the 3 main points from the document in concise sentences: understanding process management, understanding semaphores, and inter process communication.

1. Understand Process Management
• Understand Semaphores
• Inter Process Communication
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CPP TUTORIALS
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3. Recap
In last class, you have learnt :
• Multilevel Queue Scheduling
• Types of Queues
• Multilevel Feed Back Queue Scheduling
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4. Objectives
On completion of this class, you would be able to
know
• Understand Semaphores
• Inter Process Communication
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5. Semaphores
• Semaphore is basically a synchronizing tool
• Used as a solution to critical section problems
What is critical section?
– To control access to shared resources, we declare a
section of code to be critical
– We regulate access to that section
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6. Semaphores
Example :
• System consisting of n threads {TO, T1…Tn-1}
• Each thread has a segment of code, called “critical section”
• Where the thread may be changing common variables,
updating a table & so on
• Important feature of a system is that, when one thread is
executing in its critical section, no other thread is allowed
to execute in its critical section 6

7. Semaphores
•Semaphore is used to identify whether the operation is to
be executed or the CPU has to wait
• Semaphore is an integer, it is accessed through two
operations ie. wait and signal
• Wait is used to test for operation
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• Signal is used to increment the integer

8. Interprocess Communication
• Inter process communication provides a mechanism
•to allow processes to communicate and to synchronize
their actions
•without sharing the same address space
• IPC is provided by message passing systems
• If a Process want to communicate they must send
message and receive messages from each other via a
communication link existing between them
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9. Interprocess Communication

10. Interprocess Communication
• This link can be implemented in many ways
– Direct or Indirect communication
– Symmetric or Asymmetric communication
– Automatic or Explicit buffering
– Send a copy directly or Send by reference
– Fixed sized or Variable sized messages
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11. Summary
In this class, you have learnt :
---- Critical Section problem
---- Semaphores
---- Inter Process Communication
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12. Frequently Asked Questions
1. What is a Semaphores?
2. Explain Critical Section problem
3. Explain Inter Process Communication
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13. QUIZ
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14. 1. Semaphore is basically a ---------- tool
a) Critical section
b) A synchronous
c) Synchronizing
d) None
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15. 2. --------- is used to identify whether the operation is
to be executed or the CPU has to wait
a) Critical – Section
b) Semaphore
c) Both
d) None
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16. 3. ---------is provided by message passing systems
a) Critical section
b) Semaphore
c) IPC
d) None
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17. 4. Semaphore is an integer it is accessed through ----
a) IPC
b) Critical section
c) Wait & signal
d) None
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18. Other subject materials
• Web designing
• Micro processors
• C++ tutorials
• java
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