分层架构可以让我们更容易做横向扩展。如果系统没有分层，当流量增加时我们需要针对整体系统来做扩展。但是，如果我们按照上面提到的三层架构将系统分层后，那么我们就可以针对具体的问题来做细致的扩展

缓存技术蕴含的是空间换时间的思想；压缩体现的是时间换空间的思想；分布式思想也最初体现在 CPU 的设计和实现上

普通磁盘的寻道时间是 10ms 左右，而相比于磁盘寻道花费的时间，CPU 执行指令和内存寻址的时间都在是 ns（纳秒）级别，从千兆网卡上读取数据的时间是在μs（微秒）级别

某些层次负责的是对下层不同实现的抽象，从而对上层屏蔽实现细节。比方说 VFS 对上层（系统调用层）来说提供了统一的调用接口，同时对下层中不同的文件系统规约了实现模型，当新增一种文件系统实现的时候，只需要按照这种模型来设计，就可以无缝插入到 Linux 文件系统中

分层架构需要考虑的另一个因素，是层次之间一定是相邻层互相依赖，数据的流转也只能在相邻的两层之间流转

Happens-Before 并不是说前面一个操作发生在后续操作的前面，它真正要表达的是：前面一个操作的结果对后续操作是可见的

导致可见性的原因是缓存，导致有序性的原因是编译优化，那解决可见性、有序性最直接的办法就是禁用缓存和编译优化

Java 内存模型在 1.5 版本对 volatile 语义进行了增强。怎么增强的呢？答案是一项 Happens-Before 规则

Java 内存模型规范了 JVM 如何提供按需禁用缓存和编译优化的方法

final 修饰变量时，初衷是告诉编译器：这个变量生而不变，可以可劲儿优化

“同一时刻只有一个线程执行”这个条件非常重要，我们称之为互斥。如果我们能够保证对共享变量的修改是互斥的，那么，无论是单核 CPU 还是多核 CPU，就都能保证原子性了。

一个或者多个操作在 CPU 执行的过程中不被中断的特性，称为“原子性”

使用 watch 选项允许我们执行异步操作 (访问一个 API)，限制我们执行该操作的频率，并在我们得到最终结果前，设置中间状态。这些都是计算属性无法做到的

如果 <navigation-link> 没有包含一个 <slot> 元素，则该组件起始标签和结束标签之间的任何内容都会被抛弃。

计算属性是基于它们的响应式依赖进行缓存的。只在相关响应式依赖发生改变时它们才会重新求值。这就意味着只要 message 还没有发生改变，多次访问 reversedMessage 计算属性会立即返回之前的计算结果，而不必再次执行函数

组件是可复用的 Vue 实例，所以它们与 new Vue 接收相同的选项，例如 data、computed、watch、methods 以及生命周期钩子等。仅有的例外是像 el 这样根实例特有的选项

My general attitude to life is to enjoy every minute of every day. I never do anything with a feeling of, 'Oh God, I've got to do this today.'

The two things that got everyone's attention about the 'House of Cards' deal was the two-season commitment and David Fincher. After David Fincher directs a series for Netflix, no one else can say, 'Well, I'm not going to direct a series for the Internet.'

I'm still learning a lot as a songwriter. I try to write down and make a note of ideas that I cross paths with on a day-to-day basis, whether it be a conversation or something I hear on the radio, seeing a movie, or just thoughts in my head as I'm walking down the street.

I grew up with an extremely funny dad, and my mom is super funny.

I started to learn Greek when I was in high school, the last year of high school, by accident, because my teacher knew Greek and she offered to teach me on the lunch hour, so we did it in an informal way, and then I did it at university, and that was the main thing of my life.

I sat next to Carl Bernstein throughout Watergate, and Woodward would come over, and they would argue everything out, so I was really tuned into what happened.

Usually, one's cooking is better than one thinks it is.

Winning HOYS set me up for the future and prepared me for riding in front of lots of people, but the real highlight was the London 2012 Olympics. Being able to go out in front of thousands of people, on your home ground, representing your country and winning gold medals is something I'll never be able to beat.

When I was thirteen I only wanted to be a drummer.

I worked with people like Edward Snowden. Well, not people who took stuff home.

I feel most comfortable keeping versatile when it comes to music genres.

The hardest thing to explain is the glaringly evident which everybody had decided not to see.

Everybody in Spain is sick of me. But in America, there's curiosity about the new kid on the block who doesn't speak English very well. The attention makes me feel vulnerable, which is something I hadn't felt in a while. But I like it.

Awareness is not an idea about awareness, as it is not thought at all. Awareness allows you to feel life as it's happening, as it is in perception that consciousness and all spiritual qualities are manifest.

Asking me to choose between a traditional book and a Kindle is like asking me which of my dogs I love most.

I'm really getting into acting and TV. 'Sports Illustrated' is a big, iconic brand I'd like to work for, too. But TV and acting is really funny and a bit more exciting than shooting all the time.

Our greatest happiness does not depend on the condition of life in which chance has placed us, but is always the result of a good conscience, good health, occupation, and freedom in all just pursuits.

Natural grass is a wonderful thing for little bugs and sinkerball pitchers

Most important, don't do anything you don't want.

World peace is not something that can be realized simply by politicians signing treaties, or by business leaders creating economic cooperation. True and lasting peace will be realized only by forging bonds of trust between people at the deepest level, in the depths of their very lives.

The point of the spiritual revolution is not to become a good Buddhist but to become a wise and compassionate human being to awaken from our life of complacency and ignorance and to be a buddha.

My father was a prosperous hatter-farmer - making hats for the local markets during the winter months, tilling his little ten-acre farm during the summer time.

I remember back when I was a kid there was a comic strip called Plastic Man. His body was elastic and he could make his extremities as long as he wanted. As a youngster I didn't fully appreciate. But I'm now thinking Plastic Man was probably pretty popular with the ladies.

Legislation won't necessarily start a riot. But the right song can make someone pick up a chair.