Operating System
Q193.
Which of the following need not necessarily be saved on a Context Switch between processes?Q195.
What is the name of the technique in which the operating system of a computer executes several programs concurrently by switching back and forth between them?Q199.
Consider a computer system with multiple shared resource types, with one instance per resource type. Each instance can be owned by only one process at a time. Owning and freeing of resources are done by holding a global lock (L). The following scheme is used to own a resource instance: function OWNRESOURCE(Resource R) Acquire lock L // a global lock if R is available then Acquire R Release lock L else if R is owned by another process P then Terminate P, after releasing all resources owned by P Acquire R Restart P Release lock L end if end if end functionWhich of the following choice(s) about the above scheme is/are correct?[MSQ]Q200.
Consider the two functions incr and decr shown below. incr(){ wait(s); X = X+1; signal(s); } decr(){ wait(s); X = X-1; signal(s); } There are 5 threads each invoking incr once, and 3 threads each invoking decr once, on the same shared variable X. The initial value of X is 10. Suppose there are two implementations of the semaphore s, as follows: I-1: s is a binary semaphore initialized to 1. I-2: s is a counting semaphore initialized to 2. Let V1, V2 be the values of X at the end of execution of all the threads with implementations I-1, I-2, respectively. Which one of the following choices corresponds to the minimum possible values of V1, V2, respectively?