At 05:47 PM 11/8/95 -0800, Raph Levien wrote:
So let me rephrase the question: what's the minimum number of entropy bits that can be used and still give you that warm and fuzzy feeling that you don't have to worry about the possibility that the message might be corrupted?
I guess that if comet hits the earth and exterminates the human race you would not be unduly worried by a corrupted message, so let us make the odds equal to human civilization being destroyed on the same day. We get roughly one massive extinction every hundred million years, or so and a smaller blast that would demolish our technology every ten million years or So the probability of an error was equal to the human race and most major species being destroyed the same day, you would not be unduly worried. Probability of human civilization and all large animals being wiped out by comet impact tonight is 2.7E-11, so thirty five bits should be sufficient. But, if you want to feel really comfortable, make it forty bits. The probability of hitting a forty bit combination by chance is equal to the probability that all large animals on earth will be wiped out by comet impact in the next three quarters of an hour. But you might have a million lines, and send a million messages, each of a million lines. So let us make the probability that one of those fails equal to the chance that all large animals on earth get wiped out in the next half hour. Well in that case make it eighty bits. --------------------------------------------------------------------- | We have the right to defend ourselves | http://www.jim.com/jamesd/ and our property, because of the kind | of animals that we are. True law | James A. Donald derives from this right, not from the | arbitrary power of the state. | jamesd@echeque.com