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Latency

  • The time it takes an operation to complete in a system

Examples of Orders of Magnitudes

  • Reading 1 MB from computer memory
    • 250 $\mu$s (0.25 ms)
  • Reading 1 MB from SSD
    • 1000 $\mu$s (1 ms)
  • Transferring 1 MB over the network
    • 10,000 $\mu$s (10 ms)
  • Reading 1 MB from HDD
    • 20,000 $\mu$s (20 ms)
  • Inter-continental round trip
    • 150,000 $\mu$s (150 ms)

Computer Science System Design