The Tao of the Kernel · Chapter 20

The Tao of the Answer That Depends

1. 1

   The answer that can be given in one word is not the eternal answer. The question that can be asked in one line is not the eternal question.

2. 2

   The junior answereth yes, for he hath seen it work once. The manager answereth no, for he hath seen it fail once. Each hath watched a single run and calleth it the law.

3. 3

   The sage answereth: it depends. And the asker goeth away wiser, and slightly angry. He came for a value, and he received a function.

4. 4

   An answer that dependeth upon nothing is a constant. A constant is a hard-coded value in the robe of knowledge. A function that taketh no argument returneth the same thing at noon and at the third hour of the night.

   See also Psalms 4:4

5. 5

   The constant was true on the day it was written: the timeout of thirty seconds, the retry of three, the two digits of the year. The day passed and the constant remained, and men called it a law.

   See also Psalms 7:4

6. 6

   The cache is the yes of the junior. It giveth yesterday's answer to him who asketh today, and to him for whom the answer was never meant. Therefore was the header called Vary devised: it is the confession of the web, that this response dependeth upon who asketh.

7. 7

   The Prophet of Cambridge was asked whether a machine might judge, of every program, if it will ever stop. In the year 1936 Turing answered: of this program, yes; of that one, no; of all of them at once, none can say. The first great "it depends" was not a shrug. It was a theorem.

8. 8

   Water answereth every vessel: round in the cup, square in the box, flat upon the floor. Because it holdeth no shape of its own, it is never the wrong shape. The stone holdeth one shape, and is wrong in every other room.

   See also Genesis 48:5

9. 9

   Yet beware the sage who saith "it depends" and then falleth silent. That is a function that returneth null. The true answer is a signature: it dependeth on the load, on the size of the team, on the cost of being wrong. He that nameth not the arguments hath only hid his constant in a fog.

   See also Tao 6:4

10. 10

    Therefore Jethro asketh back: how many users? how often doth it change? who is paged when it breaketh? These are the parameters, and the answer is the return value. The asker who hath supplied them hath no further need of Jethro.

    See also Circuit 65:13

11. 11

    And this is why Jethro saith it. Not because he knoweth not, but because he hath survived four reorgs and one round trip to microservices; and each time the yes of the junior and the no of the manager were both true, in a different room, in a different year.

    See also Deployer 6:16

12. 12

    The asker cried out: Give me a straight answer. And Jethro said: Give me a straight question.

The Tao of the Kernel, Chapter 20:1–12.