distributed - Physical Clocks: Correctness vs. Accuracy -


in context of studying class on distributed systems stumbled upon following definitions not understand:

  • let c(t) perfect clock.
  • a clock ci(t) called correct @ time t if ci(t) = c(t).
  • a clock ci(t) called accurate @ time t if dci(t)/dt = dc(t)/dt ≡ 1.

question 1: definition of correctness means, how accuracy different it?

question 2: what's d about? not mathematical explaination appreciated.

thank in advance!

without more symbols, mathematical conceptually: accuracy means clock changing @ same rate perfect clock. correctness means clocks register same time. d derivative - can check calculus book, or wikipedia. t means time, change of imperfect/perfect clock respect time.


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