Principle Stash

Comic

Chart on a log scale of steps from 1 to 100,000. Three curves show the chance that the whole job has zero errors when each step is 99%, 99.9% or 99.99% right. Each stays near 100% at first, then collapses, passing 37% at 100, 1,000 and 10,000 steps respectively. A note with an arrow to the red curve's 100-step point reads: Even if each step has a 1% error rate, a 100-step job finishes with no errors only 37% of the time.

The Compounding Tax

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Every one of these curves shipped a demo that worked.

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Appears in Reliable Machines From Unreliable Parts

Transcript

A chart of the chance that the whole job has zero errors against the steps in the job, on a log scale from 1 to 100k. Three curves: 99% per step, 99.9% and 99.99%. Each crosses the dashed 37% line at 100, 1,000 and 10k steps.

An arrow points at the red curve’s 100-step dot: “Even if each step has a 1% error rate, a 100-step job finishes with no errors only 37% of the time.”