Operating System unit 3

 Que:-1     What is Concurrency? Explain it with example.

 Ans:-   

•  It refers to the execution of multiple instruction sequences at the same time. 
• It occurs in an operating system when multiple process threads are executing concurrently. 
• These threads can interact with one another via shared memory or message passing. 
• Concurrency results in resource sharing, which causes issues like deadlocks and resource scarcity. 
• It aids with techniques such as process coordination, memory allocation, and execution schedule to maximize throughput.

Que:-2    Explain Message Passing with example.

Ans:-

Message Passing provides a mechanism to allow processes to communicate and to synchronize their actions without sharing the same address space.

For example − chat programs on World Wide Web.

Now let us discuss the message passing step by step.

Step 1 − Message passing provides two operations which are as follows −

• Send message

• Receive message

Messages sent by a process can be either fixed or variable size.

Step 2 − For fixed size messages the system level implementation is straight forward. It makes the task of programming more difficult.

Step 3 − The variable sized messages require a more system level implementation but the programming task becomes simpler.

Step 4 − If process P1 and P2 want to communicate they need to send a message to and receive a message from each other that means here a communication link exists between them.

Step 5 − Methods for logically implementing a link and the send() and receive() operations.

Given below is the structure of message passing technique −