windows系统权限 ring0
用户 ring3
个人揣测，大侠们斧正。

先谢谢狐狸了，但是还是不太明白啊

期待高人解答。

给你找了点小资料。复制过来，你看看。
①内核模式     
  当CPU运行于内核模式时，一切程序都可运行。任务可以执行特权级指令，对任何I/O设备有全部的访问权，还能够访问任何虚地址和控制虚拟内存硬件。这种模式对应80x86的ring0层，操作系统的核心部分，包括设备驱动程序都运行在该模式。     
  ②用户模式     
  这个模式中，硬件防止特权指令的执行，并对内存和I/O空间的访问操作进行检查。这就允许WindowsNT4.0限制任务对各种I/O操作的访问，并捕捉违反系统完整性的任何行为。在用户模式中，运行的代码如果不通过操作系统中的某种门机制，就不能进入内核模式。在80x86处理器上，这个模式对应于ring3层，操作系统的用户接口部分以及所有的用户应用程序都运行在该级别。

请看微软出的视频，里面有对这些基本概念的详细介绍：

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//深入研究Windows内部原理系列之二：Windows体系结构-从操作系统的角度
0caK9s2c8@1M7q4)9K6b7g2)9J5c8W2)9J5c8X3c8G2N6$3&6D9L8$3q4V1i4K6u0W2L8h3W2U0M7X3!0K6L8$3k6@1i4K6u0W2j5$3!0E0i4K6u0r3k6r3!0%4L8X3I4G2j5h3c8Q4x3V1j5@1i4K6u0r3x3q4)9J5c8U0c8Q4x3V1j5@1x3o6c8X3z5o6R3$3y4#2)9J5k6o6l9^5y4e0u0Q4x3X3b7@1j5U0c8U0i4K6u0V1z5e0S2U0x3q4)9J5k6o6q4W2x3h3p5H3j5e0j5#2k6e0N6T1y4#2)9J5c8X3#2K6k6Y4b7H3x3e0t1&6x3o6N6$3P5s2m8E0i4K6u0W2P5X3W2H3
//深入研究Windows内部原理系列之三：Windows体系结构-从应用程序的角度
2d6K9s2c8@1M7q4)9K6b7g2)9J5c8W2)9J5c8X3c8G2N6$3&6D9L8$3q4V1i4K6u0W2L8h3W2U0M7X3!0K6L8$3k6@1i4K6u0W2j5$3!0E0i4K6u0r3k6r3!0%4L8X3I4G2j5h3c8Q4x3V1j5@1i4K6u0r3x3q4)9J5c8U0c8Q4x3V1j5@1x3o6c8X3z5o6R3$3y4#2)9J5k6o6l9^5y4e0u0Q4x3X3b7@1j5U0c8U0i4K6u0V1z5e0S2U0x3q4)9J5k6o6q4W2x3h3p5H3j5e0j5#2k6e0N6T1y4#2)9J5c8X3#2K6k6Y4b7H3x3e0x3H3x3o6N6$3P5s2m8E0i4K6u0W2P5X3W2H3
//深入研究Windows内部原理系列之四：Windows操作系统中的重要基本概念

最后说一句，微软的这套视频讲得非常好，建议看一下   ，加深对windows原理的理解
下载地址：
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//深入研究Windows内部原理系列之一：Windows的昨天、今天和明天
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//深入研究Windows内部原理系列之二：Windows体系结构-从操作系统的角度
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//深入研究Windows内部原理系列之三：Windows体系结构-从应用程序的角度
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//深入研究Windows内部原理系列之四：Windows操作系统中的重要基本概念
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//深入研究Windows内部原理系列之五：Windows Sysinternals工具集介绍
ee9K9s2c8@1M7q4)9K6b7g2)9J5c8W2)9J5c8X3c8G2N6$3&6D9L8$3q4V1i4K6u0W2L8h3W2U0M7X3!0K6L8$3k6@1i4K6u0W2j5$3!0E0i4K6u0r3k6r3!0%4L8X3I4G2j5h3c8Q4x3V1j5@1i4K6u0r3x3q4)9J5c8U0c8Q4x3V1j5@1x3o6c8X3z5o6R3$3y4#2)9J5k6o6l9^5y4e0u0Q4x3X3b7@1j5U0c8U0i4K6u0V1z5e0S2U0x3q4)9J5k6o6q4W2x3h3p5H3j5e0j5#2k6e0N6T1y4#2)9J5c8X3#2K6k6Y4b7H3x3U0l9I4x3o6N6$3P5s2m8E0i4K6u0W2P5X3W2H3
//深入研究Windows内部原理系列之六：Vista新特性底层揭秘
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//深入研究Windows内部原理系列之七：开机引导过程
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//深入研究Windows内部原理系列之八：内存管理揭秘
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//深入研究Windows内部原理系列之九：Windows的安全机制和实现
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//深入研究Windows内部原理系列之十：驱动和硬件的管理
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//深入研究Windows内部原理系列之十一：存储和文件系统
79eK9s2c8@1M7q4)9K6b7g2)9J5c8W2)9J5c8X3c8G2N6$3&6D9L8$3q4V1i4K6u0W2L8h3W2U0M7X3!0K6L8$3k6@1i4K6u0W2j5$3!0E0i4K6u0r3k6r3!0%4L8X3I4G2j5h3c8Q4x3V1k6V1i4K6u0r3x3g2)9J5c8X3k6Q4x3V1k6V1x3h3j5K6j5e0j5@1j5#2)9J5k6r3f1I4x3o6y4Q4x3X3b7@1z5o6f1%4i4K6u0V1j5X3j5I4z5g2)9J5k6o6t1#2x3K6b7K6k6o6V1K6y4X3k6X3k6W2)9J5c8X3#2K6k6Y4b7H3x3U0l9&6x3o6N6$3P5s2m8E0i4K6u0W2P5X3W2H3
//深入研究Windows内部原理系列之十二：网络协议的构成和实现
073K9s2c8@1M7q4)9K6b7g2)9J5c8W2)9J5c8X3c8G2N6$3&6D9L8$3q4V1i4K6u0W2L8h3W2U0M7X3!0K6L8$3k6@1i4K6u0W2j5$3!0E0i4K6u0r3k6r3!0%4L8X3I4G2j5h3c8Q4x3V1k6U0i4K6u0r3y4g2)9J5c8U0S2Q4x3V1k6U0y4e0R3K6x3$3p5#2x3W2)9J5k6o6b7K6y4e0m8Q4x3X3b7@1x3e0W2U0i4K6u0V1j5e0t1&6x3q4)9J5k6r3t1^5k6U0t1^5j5X3j5$3k6o6k6X3j5g2)9J5c8X3#2K6k6Y4b7H3x3U0p5J5x3o6N6$3P5s2m8E0i4K6u0W2P5X3W2H3
//深入研究Windows内部原理系列之十三：如何诊断和调试蓝屏错误
650K9s2c8@1M7q4)9K6b7g2)9J5c8W2)9J5c8X3c8G2N6$3&6D9L8$3q4V1i4K6u0W2L8h3W2U0M7X3!0K6L8$3k6@1i4K6u0W2j5$3!0E0i4K6u0r3k6r3!0%4L8X3I4G2j5h3c8Q4x3V1k6W2i4K6u0r3k6W2)9J5c8X3u0Q4x3V1k6W2k6X3t1%4y4U0f1$3y4W2)9J5k6o6c8S2j5e0u0Q4x3X3b7@1y4$3u0X3i4K6u0V1j5e0t1#2y4W2)9J5k6o6t1@1j5U0V1^5x3r3k6S2j5K6p5$3k6q4)9J5c8X3#2K6k6Y4b7H3x3K6l9&6x3o6N6$3P5s2m8E0i4K6u0W2P5X3W2H3
深入研究Windows内部原理系列之十四：用户模式的程序排错(上)
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//深入研究Windows内部原理系列之十五：用户模式的程序排错(下)
b8aK9s2c8@1M7q4)9K6b7g2)9J5c8W2)9J5c8X3c8G2N6$3&6D9L8$3q4V1i4K6u0W2L8h3W2U0M7X3!0K6L8$3k6@1i4K6u0W2j5$3!0E0i4K6u0r3k6r3!0%4L8X3I4G2j5h3c8Q4x3V1j5@1i4K6u0r3k6W2)9J5c8X3u0Q4x3V1j5@1k6X3t1^5z5h3q4S2y4q4)9J5k6o6y4U0x3h3u0Q4x3X3b7@1x3o6l9#2i4K6u0V1z5r3k6W2y4W2)9J5k6r3t1$3y4h3y4X3x3r3g2W2y4U0x3&6y4W2)9J5c8X3#2K6k6Y4b7H3x3K6p5#2x3o6N6$3P5s2m8E0i4K6u0W2P5X3W2H3
//深入研究Windows内部原理系列之十六：使您成为Windows专家的一些学习习惯

好东西，赞一个

Windows是运行在保护模式下的
把内存资源和cpu资源分等级的
系统程序运行在0级，拥有最大的权限，可以直接利用硬件资源，用户权限的程序是运行在3级的
3级的程序是不能访问0、1、2级的资源的，这些资源对3级是透明的，3级只能通过0、1、2级程序的提供的接口，才能访问更底层的资源
总之，用户权限是没有系统权限大的（至少从资源访问上来说是这样的）

若是安全方面
系统权限和管理员权限差不多，不过还是有差别的