Fill in the missing step in the following deadlock situation. Two users from the local board of education are each running a program (P1 and P2), and both programs will eventually need two tape drives to copy files from one tape to another. Only two tape drives are available and they're allocated on an "as requested" basis. Soon the following sequence transpires: 1. P1 requests tape drive 1 and gets it.
2) ____
3) P1 requests tape drive 2 but is blocked.
4) P2 requests tape drive 1 but is blocked.
A) P1 requests tape drive 2.
B) P2 requests tape drive 2 and gets it.
C) P2 requests tape drive 1 but is blocked.
D) P1 releases tape drive 1.

Question

Quizplus · Accepted Answer

The missing step is that P2 requests tape drive 2 and gets it. This breaks the deadlock as now both P1 and P2 have one tape drive and can continue their operations. If P2 requested tape drive 1 in step 2, then the deadlock would have continued as both P1 and P2 would have been blocked waiting for the other tape drive.

Fill in the Missing Step in the Following Deadlock Situation