Virtual Labs

Physical Clocks and Clock Synchronization

What is the primary purpose of a physical clock in a computer?

a: To keep track of the date Explanation

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b: To measure the passage of time Explanation

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c: To synchronize with other computers Explanation

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d: To generate random numbers Explanation

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What is clock skew?

a: The time it takes for a clock to start Explanation

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b: The difference in time between two clocks Explanation

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c: The speed at which a clock runs Explanation

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d: The time it takes to synchronize a clock Explanation

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Why is clock synchronization important in distributed systems?

a: To ensure all computers have the same hardware Explanation

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b: To coordinate actions between processes Explanation

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c: To reduce network latency Explanation

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d: To improve the performance of individual computers Explanation

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In Cristian's algorithm, how does the client estimate the one-way network delay?

a: It asks the server for the delay Explanation

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b: It assumes the delay is zero Explanation

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c: It measures the round-trip time and divides by two Explanation

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d: It uses a constant value for the delay Explanation

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What is a potential problem with Cristian's algorithm if the network delay is highly variable?

a: The client's clock will run faster Explanation

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b: The client's clock will run slower Explanation

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c: The synchronization will be inaccurate Explanation

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d: The server will crash Explanation

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What is the role of a time server in clock synchronization?

a: To provide a reference time Explanation

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b: To slow down the clocks of clients Explanation

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c: To speed up the clocks of clients Explanation

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d: To stop the clocks of clients Explanation

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How does NTP improve upon Cristian's algorithm?

a: It uses a single time server Explanation

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b: It ignores network delay Explanation

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c: It uses a hierarchical system of time servers and statistical filtering Explanation

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d: It only works on local networks Explanation

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What is a stratum 1 NTP server?

a: A server that is not synchronized Explanation

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b: A server that is synchronized with a client Explanation

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c: A server that is synchronized with an atomic clock or GPS Explanation

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d: A server that is synchronized with another stratum 1 server Explanation

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If a client's clock is ahead of the server's clock, what should the client do after receiving the server's time?

a: Set its clock forward Explanation

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b: Set its clock backward Explanation

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c: Do nothing Explanation

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d: Ask the server to change its clock Explanation

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