Given 3 concurrent processes P1, P2 and P3, we suppose that initially the shared variable x = 4. a) List all the possible values for x. b) Use one or more semaphores (use primitives signal and wait) in order to get x=13.1 c) Can we use only one semaphore to get x=11? Explain your answer. P1 P2 x=x-2; P3 ... x=x*3;

Consider a computer environment in which there are 4 magnetic drives, 2 printers, 3 scanners, and 1 optical drive. Three processes P1, P2, P3 are using these resources. At any point in time, the allocations and requests for these resources are as follows. Allocations: Magnetic drive Printer Scanner Optical drive P1 1 P2 2 1 P3 1 Requests: Magnetic drive 2 Printer Scanner Optical drive P1 1 P2 1 1 P3 2 1 Is there any way that the processes can complete without deadlock? If yes, explain how. If not, explain why not.

Write a C program that takes a list of command line arguments, each of which is the full path of a command (such as /bin/ls, /bin/ps, /bin/date, /bin/who, /bin/uname etc). Assume the number of such commands is N, your program would then create N direct child processes (ie, the parent of these child processes is the same original process), each of which executing one of the N commands. You should make sure that these N commands are executed concurrently, not sequentially one after the other. The parent process should be waiting for each child process to terminate. When a child process terminates, the parent process should print one line on the standard output stating that the relevant command has completed successfully or not successfully (such as "Command /bin/who has completed successfully", or "Command /bin/who has not completed successfully"). Once all of its child processes have terminated, the parent process should print "All done, bye-bye!" before it itself terminates. Note: do…

Code must be in C/C++ language using MPI Suppose comm_sz = 8 and the vector x = (0,1,2,...,15) has been distributed among the processes using a block distribution. Implement an allgather operation using a butterfly structured communication (see diagram below) and point-to-point communication functions

Concurrent Processes / Monitors select which is true options: a CV (condition variable) queues in a monitor store suspended processes waiting on the corresponding condition.      b The "Signal and Wait" approach (Hoare semantics) leads to more efficient implementation and reduces the number of context switches. c Two or more processes can be active in the same monitor simultaneously. d When the "Signal and Continue"-approach (Mesa semantics) is applied, the signaling process P continues executing.  e The monitor-based solution to the Dining-Philosophers problem discussed in class is restricted to 5 philosophers.