From <
http://www.catb.org/~esr//jargon/html/koans.html>:
A novice was trying to fix a broken Lisp machine by turning the
power off and on.
Knight, seeing what the student was doing, spoke sternly: “You
cannot fix a machine by just power-cycling it with no
understanding of what is going wrong.”
Knight turned the machine off and on.
The machine worked.
Commentary:
Rule 1 of power-cycling hardware: watch out for residuals. It takes
time for residual charge to drain out of the circuitry when you turn
it off. If you switch it on too quickly, the circuits are liable to
get into an inconsistent state.
For simpler circuitry, count five seconds after switching off before
switching on again. More complex components might take longer.
----
One day a student came to Moon and said: “I understand how to make
a better garbage collector. We must keep a reference count of the
pointers to each cons.”
Moon patiently told the student the following story:
“One day a student came to Moon and said: ‘I understand how to
make a better garbage collector...
[Ed. note: Pure reference-count garbage collectors have problems
with circular structures that point to themselves.]
Commentary:
Pure garbage collectors will easily consume all of RAM if you let
them. Reference-counting is a well-known technique for keeping RAM
usage within reasonable bounds in many common scenarios. The best
scheme is a combination of both. Languages like Perl and Python are
exemplars of this. Maybe the Lisps could learn from them?
----
In the days when Sussman was a novice, Minsky once came to him as
he sat hacking at the PDP-6.
“What are you doing?”, asked Minsky.
“I am training a randomly wired neural net to play Tic-Tac-Toe”
Sussman replied.
“Why is the net wired randomly?”, asked Minsky.
“I do not want it to have any preconceptions of how to play”,
Sussman said.
Minsky then shut his eyes.
“Why do you close your eyes?”, Sussman asked his teacher.
“So that the room will be empty.”
At that moment, Sussman was enlightened.
Commentary:
I wonder if either of them had heard of genetic algorithms?
----
A disciple of another sect once came to Drescher as he was eating
his morning meal.
“I would like to give you this personality test”, said the
outsider, “because I want you to be happy.”
Drescher took the paper that was offered him and put it into the
toaster, saying: “I wish the toaster to be happy, too.”
Commentary:
What can I say, but be careful what you wish for?
<
https://www.youtube.com/watch?v=LRq_SAuQDec>