2.1 信息的存储通常情况下，程序将内存视为一个非常大的数组，数组的元素是由一个个的字节Byte组成，每个字节都有一个唯一的数字来表示，称为地址address，所有地址的集合称为虚拟地址空间 2.1.1 进制1个字节由8个位bit组成，用十

1.2 操作系统无论是shell程序还是hello程序，都没有直接访问键盘、显示器、磁盘等硬件设备，真正操控硬件的是操作系统，可以把操作系统看成是应用程序和硬件之间的中间层，所有应用程序对硬件的操作必须通过操作系统来完成 为了实现上述功能

1.1 hello程序1.1.1 编译系统如何工作#include <stdio.h> int main() { printf("hello,world\n"); return 0; } 编写一个

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