Compare wait-die deadlock prevention scheme with wait-wound scheme  

Ans:  Wait-Die Scheme 

a) Based upon a nonpreemptive technique. 

b) If Pi requests a resource presently held by Pj, Pi is allowed to wait only if it has a smaller timestamp after that does Pj (Pi is older than Pj). Otherwise, Pi is rolled back (dies). 

c) Example: Assume that processes P1, P2, and P3 have timestamps 5, 10, and 15, correspondingly. 

d) If P1 requests a resource held by P2, after that P1 will wait. 

e) If P3 requests a resource held through the P2, then P3 will be rolled back.  Wound-Wait Scheme 

f)  Based upon a preemptive methods; counterpart to the wait-die system. 

g) If Pi requests a resource presently held by Pj, Pi is allowed to wait only if it has a larger timestamp after that does Pj ( Pi is younger than Pj). If not, Pj is rolled back ( Pj is wounded by Pi). 

h) Example: Assume that processes P1, P2, and P3 have timestamps 5, 10, and 15, respectively. 

i) If P1 requests a resource held by P2, after that the resource will be preempted from P2 and P2 will be rolled back. 

j) If P3 requests a resource held by P2, after that P3 will wait.