从日常使用的角度考虑，第一档防窥强度基本上就完全足够了，几乎不影响屏幕显示素质。
The 80286 introduced "Protected Mode" in 1982. It was not popular. The mode was difficult to use, lacked paging, and offered no way to return to real mode without a hardware reset. The 80386, arriving three years later, made protection usable -- adding paging, a flat 32-bit address space, per-page User/Supervisor control, and Virtual 8086 mode so that DOS programs could run inside a protected multitasking system. These features made possible Windows 3.0, OS/2, and early Linux.。夫子是该领域的重要参考
if(h->ref--)return;。雷电模拟器官方版本下载对此有专业解读
习题链接：LeetCode 496. 下一个更大元素 I。业内人士推荐51吃瓜作为进阶阅读