Consider the following multi-threaded code segment (in a mix of C and pseudocode), invoked by two processes P1 and P2, and each of the processes spawns two threads T1 and T2:

int x = 0; // global

Lock L1; // global

main() {

create a thread to execute foo(); // Thread T1

create a thread to execute foo(); // Thread T2

wait for the two threads to finish execution;

print (x);}

foo() {

int y = 0;

Acquire L1;

x = x + 1;

y = y + 1;

Release L1;

print (y); }

Which of the following statement(s) is/are correct ?

Consider a three-level page table to translate a 39-bit virtual address to a physical address as shown below.

The page size is 4 KB (1 KB = 2¹⁰ bytes) and page table entry size at every level is 8 bytes. A process P is currently using 2 GB (1 GB = 2³⁰ bytes) virtual memory which is mapped to 2 GB of physical memory. The minimum amount of memory required for the page table of P across all levels is _______ KB.

Consider the following ANSI C function:

int SomeFunction (int x, int y)

{

if ( (x == 1) I I (y == 1)) return 1;

if (x == y) return x;

if (x > y) return SomeFunction(x - y, y);

if (y > x) return SomeFunction(x, y - x);

}

The value returned by SomeFunction(15, 255) is _______.