ISRO CS 2020

Question 41

Which of the following algorithms defines time quantum ?

• shortest job scheduling algorithm
• round robin scheduling algorithm
• priority scheduling algorithm
• multilevel queue scheduling algorithm

Question 42

Dispatch latency is defined as

• the speed of dispatching a process from running to the ready state
• the time of dispatching a process from running to ready state and keeping the CPU idle
• the time to stop one process and start running another one
• none of these

Question 43

An aid to determine the deadlock occurrence is

• resource allocation graph
• starvation graph
• inversion graph
• none of the above

Question 44

Consider the following page reference string.

1 2 3 4 2 1 5 6 2 1 2 3 7 6 3 2 1 2 3 6 

What are the minimum number of frames required to get a single page fault for the above sequence assuming LRU replacement strategy ?

• 7
• 4
• 6
• 5

Question 45

Three CPU-bound tasks, with execution times of 15, 12 and 5 time units respectively arrive at times 0, t and 8, respectively. If the operating system implements a shortest remaining time first scheduling algorithm, what should be the value of t to have 4 context switches ? Ignore the context switches at time 0 and at the end.

• 0 < t < 3
  
• t = 0
  
• t < = 3
  
• 3 < t < 8
  

Question 46

The post-order traversal of a binary tree is ACEDBHIGF. The pre-order traversal is

• ABCDEFGHI
• FBADCEGIH
• FABCDEGHI
• ABDCEFGIH
• None of these

Question 47

In linear hashing, if blocking factor bfr, loading factor i and file buckets N are known, the number of records will be

• cr = i + bfr + N
• r = i – bfr – N
• r = i – bfr – N
• r = i * bfr * N

Question 48

What is compaction refers to

• a technique for overcoming internal fragmentation
• a paging technique
• a technique for overcoming external fragmentation
• a technique for compressing the data

Question 49

The operating system and the other processes are protected from being modified by an already running process because

• they run at different time instants and not in parallel
• they are in different logical addresses
• they use a protection algorithm in the scheduler
• every address generated by the CPU is being checked against the relocation and limit parameters

Question 50

A grammar is defined as

A → BC
B → x⏐Bx
C → B⏐D
D → y⏐Ey
E → z 

The non-terminal alphabet of the grammar is

• {A, B, C, D, E}
• {B, C D, E}
• {A, B, C, D, E, x, y, z}
• {x, y, z}