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AP Computer Science Principles Practice Quiz: Fault Tolerance

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Test your understanding with short quizzes. This quiz has 15 questions to check your progress.

Question 1 of 15

What is the term for a system that can continue to function even when some of its components fail?

All Questions (15)

What is the term for a system that can continue to function even when some of its components fail?

A) Fault-tolerant

B) Redundant

C) Scalable

D) Abstracted

Correct Answer: A

According to the provided content, 'When a system can support failures and still continue to function, it is called fault-tolerant.'

The inclusion of extra components that can be used to mitigate the failure of a system is known as:

A) Abstraction

B) Routing

C) Scalability

D) Redundancy

Correct Answer: D

The content defines redundancy as 'the inclusion of extra components that can be used to mitigate failure of a system if other components fail.'

How does the principle of redundancy support the fault tolerance of the Internet?

A) By ensuring all data travels along a single, optimized path for maximum speed.

B) By providing multiple paths between devices so data can be rerouted if a connection fails.

C) By reducing the number of physical devices needed to build the network, lowering costs.

D) By centralizing all data traffic through one main server for easier management.

Correct Answer: B

The content states that one way to accomplish network redundancy is by having more than one path between devices. If a connection fails, data can be sent via a different route, which is how the system remains fault-tolerant.

According to the provided text, what is a primary benefit of building fault tolerance into a complex system like the Internet?

A) It guarantees that no component will ever fail.

B) It allows users to continue using the network even when parts of it fail unexpectedly.

C) It eliminates the need for additional resources when the network grows.

D) It simplifies the system by removing all extra components.

Correct Answer: B

The text states that fault tolerance is important because 'elements of complex systems fail at unexpected times... and fault tolerance allows users to continue to use the network.'

A network is designed with only one possible path connecting a user's computer to a central server. What is the primary vulnerability of this design?

A) The design is too redundant, increasing costs unnecessarily.

B) The failure of any single device or connection on that path will cut off the user's access.

C) The network will be unable to scale to support more users.

D) Data transmission speeds will be slower than on a redundant network.

Correct Answer: B

This design lacks redundancy. As identified in the content, having more than one path is a key to fault tolerance. A single path represents a vulnerability to failure, as there is no alternative route if it fails.

What is a direct consequence of a device or connection failing on the fault-tolerant Internet?

A) The entire network must be shut down for repairs.

B) All data currently being sent is permanently lost.

C) Subsequent data will be rerouted through a different path, if possible.

D) The sender is immediately blocked from sending any more data.

Correct Answer: C

The content explicitly states, 'If a particular device or connection on the Internet fails, subsequent data will be sent via a different route, if possible.'

What is the trade-off mentioned in the text for implementing redundancy within a system?

A) It decreases the overall speed of the system.

B) It makes the system less reliable.

C) It requires additional resources.

D) It limits the number of users the system can support.

Correct Answer: C

The text notes that 'Redundancy within a system often requires additional resources but can provide the benefit of fault tolerance.'

The redundancy of routing options on the Internet increases its reliability and helps it to do what?

A) Operate without abstractions.

B) Scale to more devices and people.

C) Function with fewer components.

D) Prevent all system failures from occurring.

Correct Answer: B

The content states, 'The redundancy of routing options between two points increases the reliability of the Internet and helps it scale to more devices and more people.'

Which of the following is explicitly mentioned as being engineered to be fault tolerant?

A) A single computer

B) A specific software application

C) The Internet

D) A local area network

Correct Answer: C

The text begins by stating, 'The Internet has been engineered to be fault tolerant, with abstractions for routing and transmitting data.'

Which statement best describes the relationship between fault tolerance and redundancy?

A) They are unrelated concepts in system design.

B) A system must be redundant before it can be fault-tolerant.

C) Redundancy is a method used to achieve the goal of fault tolerance.

D) Fault tolerance is a less reliable version of redundancy.

Correct Answer: C

The content explains that redundancy (having extra components or paths) is a way to build a system that is fault-tolerant (can continue to function despite failures). Therefore, redundancy is a means to achieve fault tolerance.

A city's power grid is designed so that if one power station goes offline, other stations can automatically increase their output to reroute electricity and prevent a blackout in most areas. This design choice prioritizes:

A) Minimizing resource usage.

B) Centralized control.

C) Fault tolerance.

D) Data abstraction.

Correct Answer: C

This scenario is a direct analogy to the principles described in the text. The extra capacity and ability to reroute power (redundancy) allows the grid to continue functioning despite a component failure, which is the definition of fault tolerance.

One way to accomplish network redundancy is by having:

A) A single, high-speed connection between two devices.

B) Fewer devices connected to the network.

C) More than one path between any two connected devices.

D) A system that shuts down when any component fails.

Correct Answer: C

This is stated directly in the content: 'One way to accomplish network redundancy is by having more than one path between any two connected devices.'

Why is it important for a system to be fault-tolerant?

A) Because it guarantees the fastest possible performance.

B) Because it is the cheapest way to build a system.

C) Because elements of complex systems can fail at unexpected times.

D) Because it simplifies the routing of data by using only one path.

Correct Answer: C

The content explains that fault tolerance is important 'because elements of complex systems fail at unexpected times, often in groups, and fault tolerance allows users to continue to use the network.'

A company is building a critical data server. To ensure it is fault-tolerant, which of the following strategies aligns with the principles in the text?

A) Using a single, high-quality hard drive to store all data.

B) Connecting the server to the network via a single, high-speed cable.

C) Implementing a second, backup power supply that turns on if the main one fails.

D) Writing a software program that halts the server if any error is detected.

Correct Answer: C

This is an application of the principle of redundancy. The backup power supply is an 'extra component' that can be used to 'mitigate failure' if the primary component (the main power supply) fails, thus making the system fault-tolerant.

The Internet's ability to reroute data in response to failures is made possible by abstractions for:

A) Routing and transmitting data.

B) Storing and deleting files.

C) User authentication and authorization.

D) Hardware manufacturing and design.

Correct Answer: A

The text states, 'The Internet has been engineered to be fault tolerant, with abstractions for routing and transmitting data.' This implies these abstractions are key to its fault-tolerant nature.