Operating Syste...

The process executes the code where i is an integer:

for(i = 0; i <=15; i++)

{

if(i == 5)

continue;

fork();

if(i == 10)

break;

}

Consider a system has hit ratio as h%. Average access time to service a page fault is s milliseconds and average effective memory access time is e in milliseconds. What is the memory access time in microseconds (m is considered with service time)?

Which of the following statements are true?

(a) External Fragmentation exists when there is enough total memory space to satisfy a

request but the available space is contiguous.

(b) Memory Fragmentation can be internal as well as external.

Which of the following statement is not true about round – robin scheduling?

Which of the following statement is correct about cascading termination of a child process?

Given the Burst Time (BT) of 4 processes P1, P2, P3, and P4 as BT(t1, t2, t3, t4) – (4, 8, 6, 7), smoothening factor(α) – 0.5, and T1 = 10, what will be the burst time of process P5 for shortest Job first scheduling, using the technique of exponential averaging?

The probability that a process spends its time in performing I/O operations is 50%. In a multi programmed operating system environment, if there are 4 processes in memory at once, then the probability that all processes are waiting for I/O and the system utilization are respectively

Mutual exclusion problem occurs

Consider a system having 20 resources of same type. These resources are shared by 4 process which have peak demands of 4, 5, x, y respectively. What is the maximum value of x + y to ensure that there will be no deadlock in the system?

Consider the following scenario: A, B, C, D are processes and X, Y are resources used by the processes.

If Resources available: [X: 40 Y: 40] then what will be a safe sequence so that the processes complete execution without deadlock?

Consider a shared variable with initial value 10, this shared variable is used by four concurrent processes A, B, C and D. Process A reads the shared variable and decrements it by two and process B reads the shared variable and increment it by three before writing it to the memory. Process C reads the shared variable and decrement it by three while process D reads the shared variable and increment it by two before writing it to the memory. All the process before reading the value performs the wait operation on a counting semaphore variable S and after writing it to the memory, a signal operation is performed before the processes get terminated. Find the minimum possible value of the shared variable in the memory if S is 2?

Consider six memory partitions of size 250KB, 470KB, 600 KB, 500 KB, 300KB, and 410 KB where KB refers to kilobyte. These partitions need to be allotted to four processes of sizes 350 KB, 200 KB , 468 KB and 480 KB in that order. Which partitions are not allotted to any process when we use best fit and worst fit algorithm?

A demand - paging uses a TLB (Translation Look - aside Buffer) and single level page table stored in main memory. The memory access time is 5 μs and the page fault service time is 25 ms. If 70% of access is in TLB with no page fault and of the remaining, 20% is not present in main memory. The effective memory access time in ms is _________. (Write answer up to two decimal places)

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

A system uses FIFO policy for page replacement. It has 4 page frames with no pages loaded to begin with. The system first accesses 50 distinct pages in some order and then accesses the same 50 pages in reverse order. How many page faults will occur?

Consider the three processes P1, P2 and P3 shown below with their arrival time and burst time.

Which of the following statement is correct for this process table.

NOTE:

Time Quantum 2 units for Round robin

Consider a Unix node which maintains 16 direct blocks pointer, 2 single indirect, 4 double indirect and 8 triple indirect block pointers. Disk block size if 8 KB and disk address is 32 bits. The maximum possible size of file is ____ TB (up to 1 decimal places).

The address sequence generated by tracing a particular program executing in a pure demand paging system with 100 records per page, with 1 free main memory frame is recorded as follows. What is the number of Page Faults?

A system has n resources R₀,...., R ₁₂, and k processes P₀,...P_k-1.The implementation of the resource request logic of each process P_i is as follows:

if (i%2 == 0)

{

if (i < n) request R_i

if (i+2 < n) request R_i+2

}

else

{

if(i < n) request R_{n - i}

if (i+2 < n) request R_n-i-2

}

Maximum number of the process so deadlock is possible ______

In a certain computer, the virtual addresses are 32 bits long and the physical addresses are 48 bits long. The memory is word addressable. The page size is 16 kB and the word size is 2 bytes. The Translation Look-aside Buffer (TLB) in the address translation path has 64 valid entries. Hit ratio of TLB is 100% then maximum number of distinct virtual addresses that can be translated is _____ K.