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

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

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

Leadership is a privilege to better the lives of others. It is not an opportunity to satisfy personal greed.

There is a time for departure even when theres no certain place to go.

I want to see somebody go to jail over the financial crisis and not just black, brown and poor whites over humbles and minor drug beefs.

Promising too much can be as cruel as caring too little.

The poetical language of an age should be the current language heightened.

The entire political system is contrary to everything a feminine heart stands for. It lacks inclusion. It lacks tenderness toward children. It lacks honor for relationships. It lacks reverence for the earth. It lacks love. And without those things, the feminine psyche disconnects.

I try to sort of make myself emotional in the moment when I'm writing, and that always translates better. When I'm writing, I can't do abstract.

My job is to make sure that if you're a family in Florida, your children can get a good education and you have the opportunity for a job. That's my job and that's what I think about every day.

Everybody wants you to do good things, but in a small town you pretty much graduate and get married. Mostly you marry, have children and go to their football games.

I felt New York was a big, more stylish, more metropolitan Golders Green. I was thrilled.

The brief silence that follows is as tender as a rainstorm of daisies.

I stay off the Internet.

Republicans rarely criticize Obama for lack of empathy - in part because liberals have traditionally been seen as standing up for the weak and the vulnerable. Conservatives can be just as empathetic. But they believe that, in most cases, it's not government's role to be the primary dispenser of empathy.

Before the child ever gets to school it will have received crucial, almost irrevocable sex education and this will have been taught by the parents, who are not aware of what they are doing.

My toys were those of a boy: skates, bicycles.

I was brought up largely by my grandfather because my father only returned from a prisoner-of-war camp in 1947 and worked in the nearest small town, so I hardly ever saw him.

I was very lucky because hanging out at a golf course was much better than being on the streets. Golf taught me a great deal. I grew up surrounded by people who were professionals - lawyers, doctors, engineers. Around them, I learned how to behave, speak, eat, dress. I had nothing at home. The club was my home.

I'd rather win two or three, lose one, win two or three more. I'm a great believer in things evening out. If you win a whole bunch in a row, somewhere along the line you're going to lose some too.

I'm a chef, I own restaurants, and there's a behavior in the kitchen you have to have.

Great wits are sure to madness near allied, and thin partitions do their bounds divide.

I couldn't settle in Italy - it was like living in a foreign country.

My softer side? I mean, I like to snuggle.

The decentralized nature of online conversations often makes it easier to manipulate public opinion, both domestically and globally. Regimes that once relied on centralized systems of media control can now deliver ideological messages more subtly, with the help of little-known intermediaries like anonymous commenters on websites.

My parents were horrified when I told them I wanted to be an author.