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

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

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

A friend in power is a friend lost.

I want to be able to raise my kid. I was totally being a martyr about it at first, thinking I could totally do it on my own, which I did for a while. I've hired a babysitter before, but as for a full-time caregiver... for a control freak like me, it ain't gonna happen!

Sweet is the memory of past troubles.

Chymia, or Alchemy and Spagyrism, is the art of resolving compound bodies into their principles and of combining these again.

True wealth is not of the pocket, but of the heart and of the mind.

Lots of kids, including my son, have trouble making the leap from reading words or a few sentences in picture books to chapter books. Chapters are often long... 10 pages can seem like a lifetime to a young reader. Then reading becomes laborious and serious. That's why some of the chapters in my books are very short.

At the end of the day, the goals are simple: safety and security.

The common question that gets asked in business is, why? That's a good question, but an equally valid question is, why not?

Well goodness knows, goodness knows what historians will write.

I think films have to reach people and really grab them. That's what I hope to do when I make a film - to get under your skin and really make you think about something, and have a transporting time that takes you somewhere.

Girls that I use to try to talk to, now they want to talk to me.

It's harder to take politics seriously, to understand the issues, than it is to drown it all in a sea of scorn. And while the world cries out for greater analysis and insight, we are distracted by bread and circuses, aka the 'Great British Bake-Off' and 'Tumble.' We should rediscover our tradition of satire. Of speaking truth unto power.

Women initiate most domestic violence.

At Ford Motor Company, we believe the arts speak a common language that weaves a common thread among all people.

I hope I am a psychotherapist's dream. I've spent enough hours in therapy.

I take my Bible with me, sometimes two of them, when I travel.

Morality is not only taught; it is caught.

The 'M*A*S*H' cast loves each other with unconditional love; our domestic animals love us with unconditional love.

You may be the only person left who believes in you but its enough. It takes just one star to pierce a universe of darkness. Never give up.

There's a lot of pressure being an actor and taking on challenges that people don't expect of you.

In music, you can use metaphors with ease - if a person doesn't understand the parable, they can still enjoy the melody of the music. If, however, a person reads a book and misses the meaning of its metaphors, this will be extremely disheartening for both the reader as well as the author.

I tend not to know what the plot is or the story is or even the theme. Those things come later, for me.

I developed that for a long time. I also developed 'Sugar Sweet Science' at New Line and that didn't happen. That was a boxing movie. And between all that there were a couple of other things.

The way that people show me love on Twitter? I don't know man. It's amazing.