CS604 Current Final Term Fall 2013 Shared by Moon File 6

AOA 50% mcqs from past remaining sub + obj from handout:

1) write the safe sequence of

         Max usage      current usage     allocated

p1        8                     3                       4

p2        2                     1             

p3        8                     5 

2) write deadlock or not in given graph:

Here is a resource allocation graph with a deadlock. There are two cycles in this graph:
{P1 ¨ R1, R1 ¨ P2, P2 ¨ R3, R3 ¨ P3, P3 ¨ R2, R2 ¨ P1} and
{P2 ¨ R3, R3 ¨ P3, P3 ¨ R2, R2 ¨ P2}
No process will release an already acquired resource and the three processes will remain
in the deadlock state.

3) in DOS which mode is used for floppy disk?

4)Number of free frames = 64

Number of processes = 3
Process sizes: P1 = 10 pages; P2 = 40 pages; P3 = 127 pages
.. Fixed allocation
64/3 = 21 frames per process and one put in the free frames list
.. Proportional Allocation
.. si = Size of process Pi
.. S = S si
.. m = Number of free frames
.. ai = Allocation for Pi = (si / S) * m
.. a1 = (10 / 177) * 64 = 3 frames
.. a2 = (40 / 177) * 64 = 14 frames
.. a3 = (127 / 177) * 64 = 45 frames
.. Two free frames are put in the list of free frames

5)Tmem = 100 nsec

TTLB = 20 nsec
Hit ratio is 80%
Teffective = 0.8 (20 + 100) + 0.2 (20 + 2*100) nanoseconds = 140 nanoseconds
This means that with 80% chances of finding a page table entry in the TLB, the effective
access time becomes 40% worse than memory access time without paging.

6)Name any two which method are used in page table?

Pray for me :)