cosven
commented
5 years ago 第一章：Introduction
Number System
讲解 2 进制，10 进制，16 进制相互转换
Computer Organization
Momery
- 内存基本单位是 byte
- 所有内存中的数据都是数字(numeric)
- 通过建立 character-code 将数字与字符对应，字符也用数字存储
- 最常见的 character codes 被熟知为 ASCII
- 一个新的，更完整的用来取代 ASCII 的 character code 是 Unicode
- ASCII 用一个 byte 来编码字符，Unicode 使用 two bytes
The CPU
- CPU 是用来执行指令(instructions)，这些指令叫做 machine language。机器语言指令被编码为原始数字(raw number)
- compiler 将编程语言代码转换为对应平台的机器语言。一般来说，每种类型的 CPU 都有它自己独特的机器语言
CPU 使用时钟(clock)来同步指令的执行。时钟以固定的频率跳动。
When you buy a 1.5 GHz computer, 1.5 GHz is the frequency of this clock. The clock does not keep track of minutes and seconds. It simply beats at a constant rate. The electronics of the CPU uses the beats to perform their operations correctly, like how the beats of a metronome help one play music at the correct rhythm. The number of beats (or as they are usually called cycles) an instruction requires depends on the CPU generation and model.
上面这一段很好的解释了 1.5GHz 的含义。
书籍地址：https://pdos.csail.mit.edu/6.828/2018/readings/pcasm-book.pdf
总结：http://cosven.me/blogs/84