Consider the case of a home construction company with two application programs, purchasing (P1) and sales (P2), which are active at the same time. They each need to access two files, inventory (F1) and suppliers (F2), to update daily transactions. The following series of events will cause a deadlock. Fill in the missing event in the sequence.
1) Purchasing (P1) accesses the supplier file (F2).
2) Sales (P2) accesses the inventory file (F1).
3) Purchasing (P1) doesn't release the supplier file (F2) but requests the inventory file (F1), but P1 is blocked because F1 is being held by P2.
4) Meanwhile, ____
A) sales (P2) doesn't release the inventory file (F1) but requests the supplier file (F2)
B) sales (P2) does release the inventory file (F1) and then requests the supplier file (F2)
C) purchasing (P1) does release the supplier file (F2) which is then requested by sales (P2)
D) purchasing (P1) exits

Question

Quizplus · Accepted Answer

A deadlock occurs when two or more processes are blocked, waiting for each other's resources to be released. In this case, P1 is blocked because it is waiting for F1, which is being held by P2. P2 is also blocked because it is waiting for F2, which is being held by P1. Therefore, for the deadlock to occur, P2 must not release the inventory file (F1) but request the supplier file (F2) in step 4. This will cause P2 to be blocked, and both P1 and P2 will be waiting for each other's resources, resulting in a deadlock.

Consider the Case of a Home Construction Company with Two