# Write your own

Still, I don’t claim to be the exclusive authority on this topic; if you don’t like what you read here, write your own.

— How To Become A Hacker

— Eric Steven Raymond

— Me@2010.11.22

“Hacker” here means a highly skilled programmer, not a computer criminal. — Me

The basic difference is this: hackers build things, crackers break them. — Eric S. Raymond

2011.05.31 Tuesday ACHK

# 運算三部曲 1.2

1. 寫公式

2. 代數字

3. 出答案

F = ma

= (5kg) (10 m/s^2)

= 50 N

— Me@2011.05.31

# Principle of Least Action, 3.1

Moreover, in the usual formulation of classical action principles, the initial and final states of the system are fixed, e.g.,

Given that the particle begins at position x1 at time t1 and ends at position x2 at time t2, the physical trajectory that connects these two endpoints is an extremum of the action integral.

In particular, the fixing of the final state appears to give the action principle a teleological character which has been controversial historically. However, this apparent teleology occurs only because of the way in which the question was asked. By specifying some but not all aspects of both the initial and final conditions (the positions but not the velocities) we are making some inferences about the initial conditions from the final conditions, and it is this “backward” inference that can be mistaken for a teleological causal influence.

— Wikipedia on Principle of least action

2011.05.30 Monday ACHK

# Yoga Sutras of Patanjali

When you are inspired by some great purpose, some extraordinary project, all your thoughts break their bonds: Your mind transcends limitations, your consciousness expands in every direction, and you find yourself in a new, great, and wonderful world. Dormant forces, faculties and talents become alive, and your discover yourself to be a greater person by far than you ever dreamed yourself to be.

– Yoga Sutras of Patanjali

2011.05.30 Monday ACHK

# 十萬七千里 1.1

（安：我同意這個講法。如果我真的要在日常生活過得快樂的話，我一定要改變工作環境，轉換上司。但是，我現在沒有可能做到這一點。那我應該怎麼辦呢？）

（安：無錯。）

— Me@2011.05.29

If you wanted to have the perfect life, the thing to do would be to go to grad school, secretly write your dissertation in the first year or two, and then just enjoy yourself for the next three years, dribbling out a chapter at a time. This prospect will make grad students’ mouths water, but I know of no one who’s had the discipline to pull it off.

— Paul Graham

2011.05.29 Sunday ACHK

# 時間觀 2

Cumulative concept of time 2

Time is a counting number, not an ordering number.

— Me@2010.11.22

Time is not only an ordering number, but also a counting number.

— Me@2011.05.29

# 運算三部曲 1.1

（CSK：會不會有時驗算的時間，還多過原本運算那一題的時間？）

（CSK：你講過，考試時驗算了題目，就可以大大減輕心理壓力。那樣，有部分題目沒有驗算的話，豈不是心理壓力會很大？）

— Me@2011.05.28

# Fermions and bosons 1.2

Here’s the link between particle interchange and rotation: Look at the twist you introduced into your strip of paper. There is another way to introduce that type of twist. Instead of rotating one end, switch the position of the ends of your strip, while keeping both ends of the strip facing up.

2011.05.27 Friday ACHK

# Make yesterday obsolete

Both Page and Brin believed that the company should run like the Internet itself: fast-moving, bottom up, going to work every day to make yesterday obsolete.

— In The Plex: How Google Thinks, Works, and Shapes Our Lives, p.158

2011.05.27 Friday ACHK

# 小學生傳奇 1.5

（安：如果依你所說，假設「人是瘋狂的怪獸」的話，我都同意，我的「疑惑不安」會小很多。但是，那仍未解決「在日常生活和工作中，應如何面對和應付那些愚昧的人」的問題。）

— Me@2011.05.26

# The next Google

— Me@2011.05.26

— inspired by Seth Godin

2011.05.26 Thursday ACHK

A time to fear 2

— Me@2011.05.25

# Research

DDJ: In the presentation before the awarding of the Japan Prize today, you were quoted on the distinction between research and development. [The former, Thompson stated, was directionless, whereas development had a specific goal in mind.] So in that context, is Go experimental?

— Interview with Ken Thompson

— By Andrew Binstock, May 18, 2011

2011.05.24 Tuesday ACHK

# Compressing data

…, he described his concept of how compressing data was equivalent in many ways to understanding it.

— In The Plex: How Google Thinks, Works, and Shapes Our Lives, p.100

2011.05.24 Tuesday ACHK

# 小學生傳奇 1.4

（安：「transcend」是什麼意思？）

「transcend」不是指「解決」問題，而是更高的一個層次。「transcend」是指，直情令到該個問題，和我沒有關係，影響不到我。

（安：如果依你所說，假設「人是瘋狂的怪獸」的話，我都同意，我的「疑惑不安」會小很多。但是，那仍未解決「在日常生活和工作中，應如何面對和應付那些愚昧的人」的問題。）

— Me@2011.05.23

Haskellers never use loops – Instead, they either use recursion to do looping, or they use functions like map that take other functions as parameters.

— Conrad Barski, M.D.

2011.05.22 Sunday ACHK

— Me@2010.01.28

.

.

（CSK：那樣很困難。）

— Me@2011.05.21