Operating System Questions and Answers – Deadlock Avoidance

This set of Operating System Multiple Choice Questions & Answers (MCQs) focuses on “Deadlock Avoidance”.

1. Each request requires that the system consider the _____________ to decide whether the current request can be satisfied or must wait to avoid a future possible deadlock.
a) resources currently available
b) processes that have previously been in the system
c) resources currently allocated to each process
d) future requests and releases of each process
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2. Given a priori information about the ________ number of resources of each type that maybe requested for each process, it is possible to construct an algorithm that ensures that the system will never enter a deadlock state.
a) minimum
b) average
c) maximum
d) approximate
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3. A deadlock avoidance algorithm dynamically examines the __________ to ensure that a circular wait condition can never exist.
a) resource allocation state
b) system storage state
c) operating system
d) resources
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4. A state is safe, if ____________
a) the system does not crash due to deadlock occurrence
b) the system can allocate resources to each process in some order and still avoid a deadlock
c) the state keeps the system protected and safe
d) all of the mentioned
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5. A system is in a safe state only if there exists a ____________
a) safe allocation
b) safe resource
c) safe sequence
d) all of the mentioned
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6. All unsafe states are ____________
a) deadlocks
b) not deadlocks
c) fatal
d) none of the mentioned
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7. A system has 12 magnetic tape drives and 3 processes : P0, P1, and P2. Process P0 requires 10 tape drives, P1 requires 4 and P2 requires 9 tape drives.

Process    
P0            
P1                             
P2                             
 
Maximum needs (process-wise: P0 through P2 top to bottom)    
10             
4   
9
 
Currently allocated (process-wise)
5
2
2

Which of the following sequence is a safe sequence?
a) P0, P1, P2
b) P1, P2, P0
c) P2, P0, P1
d) P1, P0, P2
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8. If no cycle exists in the resource allocation graph ____________
a) then the system will not be in a safe state
b) then the system will be in a safe state
c) all of the mentioned
d) none of the mentioned
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9. The resource allocation graph is not applicable to a resource allocation system ____________
a) with multiple instances of each resource type
b) with a single instance of each resource type
c) single & multiple instances of each resource type
d) none of the mentioned
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10. The Banker’s algorithm is _____________ than the resource allocation graph algorithm.
a) less efficient
b) more efficient
c) equal
d) none of the mentioned
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11. The data structures available in the Banker’s algorithm are ____________
a) Available
b) Need
c) Allocation
d) All of the mentioned
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12. The content of the matrix Need is ____________
a) Allocation – Available
b) Max – Available
c) Max – Allocation
d) Allocation – Max
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13. A system with 5 processes P0 through P4 and three resource types A, B, C have A with 10 instances, B with 5 instances, and C with 7 instances. At time t0, the following snapshot has been taken:

Process
P0               
P1               
P2           
P3           
P4       
 
Allocation (process-wise : P0 through P4 top TO bottom) 
A   B   C
0   1   0
2   0   0
3   0   2
2   1   1
0   0   2
 
MAX (process-wise: P0 through P4 top TO bottom)
A   B   C
7   5   3
3   2   2
9   0   2
2   2   2
4   3   3
 
Available
A   B   C
3   3   2

The sequence <P1, P3, P4, P2, P0> leads the system to ____________
a) an unsafe state
b) a safe state
c) a protected state
d) a deadlock
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Sanfoundry Global Education & Learning Series – Operating System.