Operating Syste...

The main function of the dispatcher (the portion of the process scheduler) is:

Consider the following set of processes {A, B, C, D}, with the arrival time and the CPU burst time given in milliseconds.

What is the average waiting time in millisecond for these processes with the shortest job first algorithm? 

Suppose there is a paging system with a translation lookaside buffer. Assuming that the entire page table and all the pages are in the physical memory, what is the effective memory access time in ms if it takes 5 msec to search the TLB and 70 msec to access physical memory? The TLB hit ratio is 0.8.

Consider a computer system having R resources of the same type and these resources are shared by 6 processes that have maximum demands of 7, 5, 3, 8, 4, 6 respectively. Then for what minimum values of R, the system will not be in deadlock?

Which of the following is TRUE about user-level threads and kernel-level threads?

S₁: Typically if a user-level thread is performing blocking system call then the entire process will be blocked

S₂: Kernel level threads are designed as dependent threads

Consider a hypothetical system with byte-addressable memory, 64-bit logical addresses, 8 Megabyte page size and page table entries of 16 bytes each. What is the size of the page table in the system in terabytes?

Suppose that jobs arrive according to the following schedule :                                                 

Now give the sequence of the processes as they gets share of CPU if the scheduler used is Shortest Remaining Time First.

The process executes the code where x is an integer and x is initialized to 10

while(--x){

fork();

if(x == 2)

break;

}

A system has 12 identical resources and Y processes competing for them. Each process can request at most 3 resources. Which one of the following values of Y could lead to a deadlock?

At time 0, an OS with round-robin scheduling (time quantum = 5 units) has 5 processes P_1, P₂, P₃, P₄, P₅ with burst times 15, 10, 20, 5, 15 respectively. What is the average turn-around time?

Which of the following is/are not true about the deadlock scheme?

I.  In deadlock avoidance, number the resource uniquely and never requests a lower-numbered resource

II. In deadlock avoidance, the request for the resources is always granted if the resulting state is safe.

III. In deadlock prevention, never request a resource after releasing any resource.

Consider a counting semaphore S. The operation P(S) performs the operation S = S – 1 and operation V(S) performs the operation V = V + 1. During program execution, 13P and 5V operation is performed in the some order. Find the number of processes in a blocked state with initial counting semaphore value 1.

A computer uses 48 bits Virtual Address Space, 256 GB of physical memory with page size of 4 KB. The page table size is 4 bytes and if each entry fits in a single page the number of levels of paging required is _____.

Consider two processes P1 and P2 executing their respective codes initial values of global variables P1_inside and P2_inside are “false”.

Consider the below statements:

1. Mutual exclusion is satisfied
2. Mutual Exclusion is not satisfied
3. It is possible for deadlock

Which of the above are true?

Which of the following is true for the above-given resource allocation table?

Consider a file system that uses inodes to represent files. Disk blocks are 12 KB in size, and a pointer to a disk block requires 8 bytes. This file system has 10 direct disk blocks, as well as single and double indirect disk blocks. What is the maximum size in GB (up to two decimals) of a file that can be stored in this file system?

Consider a n-way set associative cache memory with 8 sets and 16 cache blocks (0-15) and a main memory with 512 blocks (0 - 511). What memory blocks will be present in the cache after the sequence 17, 4, 13, 105, 28, 29, 200, 408, 127, 205, 411, 251 if LRU is used as a cache replacement block?

Three CPU-bound tasks, with execution times of 15, 12 and 5 time units respectively arrive at times 0, t and 8, respectively. If the operating system implements a shortest remaining time first scheduling algorithm, what should be the value of t to have 4 context switches?