Scalar Logical time

What is the primary purpose of scalar logical clocks in distributed systems?

a: To synchronize physical time across all processes Explanation

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b: To order events in a distributed system without relying on physical time Explanation

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c: To measure network latency between processes Explanation

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d: To encrypt messages between processes Explanation

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What does the 'happens before' relation (→) represent in distributed systems?

a: Physical time ordering between events Explanation

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b: Causal ordering between events across processes Explanation

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c: Random ordering of events Explanation

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d: Alphabetical ordering of process names Explanation

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When a process sends a message, it

a: increments its clock before the send event and sends a message with the time before the increment Explanation

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b: increments its clock after the send event and sends a message with the time after the increment Explanation

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c: increments its clock after the send event and sends a message with the time before the increment Explanation

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d: increments its clock before the send event and sends a message with the time after the increment Explanation

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In a distributed system with three processes P1, P2, and P3, if event a occurs on P1 at logical time 5 and event b occurs on P2 at logical time 7, what can we conclude?

a: Event a definitely happened before event b Explanation

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b: Event b definitely happened before event a Explanation

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c: Events a and b are concurrent Explanation

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d: We cannot determine the relationship without knowing the message history Explanation

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Scalar logical clocks can be used to

a: Totally order events by themselves Explanation

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b: Can only establish Partial Ordering Explanation

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c: Can be used along with arbitrary tiebreaks to establish total ordering Explanation

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d: Can be used along with arbitrary tiebreaks to establish partial ordering Explanation

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What happens when a process receives a message in scalar logical clock systems?

a: It only increments its own clock by 1 Explanation

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b: It sets its clock to the message timestamp Explanation

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c: It sets its clock to max(own_clock, message_timestamp) and then increments Explanation

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d: It ignores the message timestamp Explanation

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When are two events considered concurrent in scalar logical time?

a: When they occur at the same physical time Explanation

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b: When neither event happens before the other (a ↛ b and b ↛ a) Explanation

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c: When they have the same logical timestamp Explanation

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d: When they occur on the same process Explanation

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If process P1 has clock value 10 and receives a message with timestamp 8, what will be P1's clock value after processing the receive event?

a: 8 Explanation

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b: 9 Explanation

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c: 10 Explanation

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d: 11 Explanation

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What is the clock condition that logical clocks must satisfy?

a: If a → b, then C(a) > C(b) Explanation

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b: If a → b, then C(a) = C(b) Explanation

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c: If a → b, then C(a) < C(b) Explanation

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d: If a → b, then C(a) ≥ C(b) Explanation

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What is strong consistency in logical clock systems?

a: a → b if and only if C(a) < C(b) Explanation

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b: a → b implies C(a) < C(b) only Explanation

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c: All processes have the same clock value at any given time Explanation

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d: Physical and logical time are synchronized Explanation

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How do scalar logical clocks handle the transitivity property of the happens-before relation?

a: By using vector timestamps Explanation

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b: By ensuring that if a → b and b → c, then C(a) < C(b) < C(c) Explanation

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c: By synchronizing physical clocks Explanation

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d: By using process IDs as tie-breakers Explanation

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Which limitation of scalar logical clocks is addressed by vector clocks?

a: Scalar clocks cannot handle message passing Explanation

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b: Scalar clocks cannot determine if two events are concurrent by comparing their timestamps Explanation

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c: Scalar clocks cannot maintain causality Explanation

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d: Scalar clocks cannot work in asynchronous systems Explanation

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