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	Translation	Source string	Target string
	Linux From Scratch/chapter09_udev — Chinese (Simplified Han script)	Udev	Udev
	Linux From Scratch/chapter09_udev — Chinese (Simplified Han script)	usage	用法
	Linux From Scratch/chapter09_udev — English	The main problem with the approach adopted by <systemitem class="filesystem">devfs</systemitem> was the way it handled device detection, creation, and naming. The latter issue, that of device node naming, was perhaps the most critical. It is generally accepted that if device names are configurable, the device naming policy should be chosen by system administrators, and not imposed on them by the developer(s). The <systemitem class="filesystem">devfs</systemitem> file system also suffered from race conditions that were inherent in its design; these could not be fixed without a substantial revision of the kernel. <systemitem class="filesystem">devfs</systemitem> was marked as deprecated for a long time, and was finally removed from the kernel in June, 2006.	The main problem with the approach adopted by <systemitem class="filesystem">devfs</systemitem> was the way it handled device detection, creation, and naming. The latter issue, that of device node naming, was perhaps the most critical. It is generally accepted that if device names are configurable, the device naming policy should be chosen by system administrators, and not imposed on them by the developer(s). The <systemitem class="filesystem">devfs</systemitem> file system also suffered from race conditions that were inherent in its design; these could not be fixed without a substantial revision of the kernel. <systemitem class="filesystem">devfs</systemitem> was marked as deprecated for a long time, and was finally removed from the kernel in June, 2006.
	Linux From Scratch/chapter09_udev — Chinese (Simplified Han script)	The main problem with the approach adopted by <systemitem class="filesystem">devfs</systemitem> was the way it handled device detection, creation, and naming. The latter issue, that of device node naming, was perhaps the most critical. It is generally accepted that if device names are configurable, the device naming policy should be chosen by system administrators, and not imposed on them by the developer(s). The <systemitem class="filesystem">devfs</systemitem> file system also suffered from race conditions that were inherent in its design; these could not be fixed without a substantial revision of the kernel. <systemitem class="filesystem">devfs</systemitem> was marked as deprecated for a long time, and was finally removed from the kernel in June, 2006.	<systemitem class="filesystem">devfs</systemitem> 实现机制的主要问题是它处理设备的检测、创建和命名的方式，其中最致命的或许最后一项，即设备节点命名方式。通常认为，如果设备名称是可配置的，那么设备命名策略应该由系统管理员，而不是某个 (某些)特定开发者决定。<systemitem class="filesystem">devfs</systemitem> 还受到其设计中固有的竞争条件的严重影响，在不对内核进行大量修改的前提下无法修复这一问题。由于缺乏维护，它早已被标记为过时特性，最终在 2006 年 6 月被从内核中移除。
	Linux From Scratch/chapter09_udev — Chinese (Simplified Han script)	The <systemitem class="filesystem">sysfs</systemitem> filesystem was mentioned briefly above. One may wonder how <systemitem class="filesystem">sysfs</systemitem> knows about the devices present on a system and what device numbers should be used for them. Drivers that have been compiled into the kernel register their objects in <systemitem class="filesystem">sysfs</systemitem> (devtmpfs internally) as they are detected by the kernel. For drivers compiled as modules, registration happens when the module is loaded. Once the <systemitem class="filesystem">sysfs</systemitem> filesystem is mounted (on <filename class="directory">/sys</filename>), data which the drivers have registered with <systemitem class="filesystem">sysfs</systemitem> are available to userspace processes and to udevd for processing (including modifications to device nodes).	前面已经简要提到了 <systemitem class="filesystem">sysfs</systemitem> 文件系统。有些读者可能好奇，<systemitem class="filesystem">sysfs</systemitem> 是如何知道系统中存在哪些设备，以及应该为它们使用什么设备号的。答案是，那些编译到内核中的驱动程序在它们的对象被内核检测到时，直接将它们注册到 <systemitem class="filesystem">sysfs</systemitem> (内部的 devtmpfs)。对于那些被编译为模块的驱动程序，注册过程在模块加载时进行。只要 <systemitem class="filesystem">sysfs</systemitem> 文件系统被挂载好 (位于 /sys)，用户空间程序即可使用驱动程序注册在 <systemitem class="filesystem">sysfs</systemitem> 中的数据，Udev 就能够使用这些数据对设备进行处理 (包括修改设备节点)。
	Linux From Scratch/chapter09_udev — Chinese (Simplified Han script)	Device drivers compiled as modules may have aliases built into them. Aliases are visible in the output of the <command>modinfo</command> program and are usually related to the bus-specific identifiers of devices supported by a module. For example, the <emphasis>snd-fm801</emphasis> driver supports PCI devices with vendor ID 0x1319 and device ID 0x0801, and has an alias of <literal>pci:v00001319d00000801sv*sd*bc04sc01i*</literal>. For most devices, the bus driver exports the alias of the driver that would handle the device via <systemitem class="filesystem">sysfs</systemitem>. E.g., the <filename>/sys/bus/pci/devices/0000:00:0d.0/modalias</filename> file might contain the string <literal>pci:v00001319d00000801sv00001319sd00001319bc04sc01i00</literal>. The default rules provided with udev will cause <command>udevd</command> to call out to <command>/sbin/modprobe</command> with the contents of the <envar>MODALIAS</envar> uevent environment variable (which should be the same as the contents of the <filename>modalias</filename> file in sysfs), thus loading all modules whose aliases match this string after wildcard expansion.	编译为内核模块的设备驱动程序可能有内建的别名。别名可以通过 <command>modinfo</command> 程序查询，它通常和该模块支持的设备的总线相关标识符有关。例如，<emphasis>snd-fm801</emphasis> 驱动程序支持厂商 ID 为 0x1319，设备 ID 为 0x0801 的 PCI 设备，其别名为<quote>pci:v00001319d00000801sv*sd*bc04sc01l*</quote>。对于多数设备，总线驱动程序会通过 <systemitem class="filesystem">sysfs</systemitem> 导出应该处理该设备的驱动程序别名，例如 <filename>/sys/bus/pci/devices/0000:00:0d.0/modalias</filename> 文件应该包含字符串<quote>pci:v00001319d00000801sv00001319sd00001319bc04sc01i00</quote>。Udev 附带的默认规则会导致 <command>udevd</command> 调用 <command>/sbin/modprobe</command> 时传递 <envar>MODALIAS</envar> uevent 环境变量 (它的值应该和 sysfs 中<filename>modalias</filename> 文件的内容相同)，从而加载那些在通配符扩展后别名与这个字符串匹配的模块。
	Linux From Scratch/chapter09_udev — Chinese (Simplified Han script)	Note that the <quote>softdep</quote> command also allows <literal>pre:</literal> dependencies, or a mixture of both <literal>pre:</literal> and <literal>post:</literal> dependencies. See the <ulink role='man' url='&man;modprobe.d.5'>modprobe.d(5)</ulink> manual page for more information on <quote>softdep</quote> syntax and capabilities.	注意<quote>softdep</quote>命令也允许 <literal>pre:</literal> 依赖项，或混合使用 <literal>pre:</literal> 和 <literal>post:</literal> 依赖项。参阅 <filename>modprobe.d(5)</filename> man 手册页面，了解更多关于<quote>softdep</quote>语法和功能的信息。