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

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

Drink! for you know not whence you came nor why: drink! for you know not why you go, nor where.

God never said that the journey would be easy but He did say that the arrival would be worthwhile.

People who've read my reviews know my tastes, know how I approach a book, know my background. I can write with believable authority. It doesn't mean I'm always right.

There is so much more vegetable use in Thailand, India and China than meat. Yes, when you go to the markets or buy street food, you see shrimp or chicken - but mostly vegetables.

I believe acting is very physical, and when you have to fight or do those kinds of things, it takes a lot of respect not to allow yourself to go off and hurt yourself or someone else.

I love the fact that people don't see the ukulele as a serious instrument. A lot of people see it as more of a toy, and I love that because it just proves that people aren't intimidated by the instrument. They aren't afraid to pick it up.

My mom played tennis for, like, six hours a day and went to college on a tennis scholarship, because that was the way she could go to school. So they instilled in me the idea that you have to work hard for the things you want in life and never complain.

And of course, now that Bernard and I have found each other forever, we're determined to create our own little world in order to survive the one we're in.

When you have a few billion people connected with screens, not voice... screens are important. You can transmit a thousand times more information.

Women don't want an overly feminine vehicle - they want to feel secure.

It's so much easier to know who you are when there aren't a thousand people telling you who they think you are.

Never marry for money; you can borrow it cheaper.

I think there are a lot of outside interests that would like to see Sarah Palin in some form of elected office. Most in Alaska recognize our former governor is really not involved in or engaged in the state anymore, that she's moved to other interests.

I come from a great family. I've seen family life and I know how wonderful, how nurturing, and how wonderful it can be.

There are no disappointments, just challenges.

My face frowns by default, so when I'm most calm is when I appear the least approachable.

Accept responsibility for your life. Know that it is you who will get you to where you want to go, no one else.

I like to relate to my kids as they are. I enjoy spending that time with them. I see that my girls are so completely different and different from me, too.

You should never meet your heroes. Paul Newman... I was so excited about meeting him, but he turned up in shell suit bottoms, slippers, and a jumper. He was just so worn out and old, he wanted to go home.

I'm healthy now. I probably wouldn't say I'm at my best fitness level and I haven't played that much lately, but I'm healthy and that's all that matters.

In the nineteenth century, in part because a ton of American men moved west, in part because of the Civil War, and in part because of trepidation about marriage, which was then a very confining institution, there was a big population of women - mostly middle-class white women on the East Coast - who didn't marry.

The fact is, America needs energy and new energy infrastructure, and the Keystone XL pipeline will help us achieve that with good stewardship.

All the things one has forgotten scream for help in dreams.

I think it's great to see how they've grown up, not just as actors but as people. They're still very much the same kids that I met many years ago. They've grown up and they are funny and wicked and naughty and bright, and I think as actors their work is just getting better and better. They've blossomed.