/dev, device file storage directory, the application through the read and write to these files and control, can access the actual equipment;
/sys/devices directory, according to the type of bus attached to the device, organized into a hierarchical structure, saving all the equipment of the system, is the file system management equipment, the most important directory structure;
This is the directory structure that the kernel devices are layered by bus type, and all the devices in the devices are connected under a certain bus, where each of the specific buses can be
Find symbolic links for each specific device, which is also part of the Linux Unified device model;
Under/sys/dev, there are two subdirectories, block and char, which store the primary and secondary numbers of blocks and character devices, in the form of (Major:minor), which point to the devices in the/sys/devices directory.
1. The SYSFS mount point is the/sys directory, SYSFS is a virtual file system (there are other virtual file systems, such as USBFS and PROCFS), SYSFS export the kernel's data structure.
2./sys/dev/and/sys/devices are SYSFS organized according to Object-oriented Management, and SYSFS are mainly used to describe the device-driven model in Linux kernel 2.6, user-state
The background program (UDEV) Dynamically periodically scans the property entries in the/sys directory to automate the management of device files (also known as device nodes), thereby establishing or deleting corresponding device files in the/dev directory.