Dynamic device management in Udev


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After three years of hanging around on the sidelines, Udev has finally ousted the legacy Dev-FS system. We take a look under the hood at the Udev device management system inside your Linux system.

Linux inherited the classic Unix adage “Everything is a file.” This abstraction has allowed programs to use device nodes (device files) to access computer hardware as if they were accessing an ordinary file. These special device files, which are opened, read, written to, or closed using the same system calls as text files, are distinguished by their names, types (block or character device), major numbers, and minor numbers. PreviouslyToo Static Device files are created by the mknod command during the installation phase, assuming legacy management. This approach creates a permanent entry in /dev for each device the admin might connect to the system at any time in the future, and this can easily mean thousands of entries.