Examine this udev device naming rule which gets processed successfully: makefile KERNEL=="hdb", DRIVER=="ide-disk", SYMLINK+="sparedisk" Which two…

The provided udev rule KERNEL=="hdb", DRIVER=="ide-disk", SYMLINK+="sparedisk" is processed based on a set of conditions and an action. The comma separating the key-value pairs acts as a logical AND operator. Therefore, the rule will only trigger if a device event occurs where the kernel-assigned name is "hdb" and the device is using the "ide-disk" driver. The SYMLINK+="sparedisk" directive instructs udev to create a symbolic link named /dev/sparedisk that points to the actual device node, which is /dev/hdb. This does not rename the original device node; it only provides an additional, persistent name.

A. The += operator adds a value to a list for the current device; the term "overwriting" is imprecise for how udev manages the /dev namespace.

B. The SYMLINK key creates a symbolic link, it does not rename the device. The NAME key is used for renaming the device node itself.

E. The comma separating match keys in a udev rule implies a logical AND, not an OR. Both conditions must be true for the rule to be applied.

1. udev(7) man page: "A rule is a set of one or more key-value pairs. If all keys match their values

the rule is applied... KERNEL==: Match the kernel name for the device... DRIVER==: Match the driver name for the device... SYMLINK=: The name of a symbolic link to be created for the device node." This confirms that all conditions must match (AND logic) and that SYMLINK creates a link

not a rename. (Source: man udev.rules(7) on Oracle Linux 7/8).

2. Oracle Linux 7 Documentation

Administrator's Guide

Chapter 26. Managing Devices with udev

Section 26.2. Udev Rules: "All conditions in a rule must be met for the rule to be applied... The SYMLINK key is used to create a symbolic link to the device node." This official vendor documentation confirms the AND logic of the rule and the function of the SYMLINK key.

3. Red Hat Enterprise Linux 7

Storage Administration Guide

Chapter 5. Managing Storage Devices with udev: "A udev rule is composed of one or more key-value pairs separated by a comma... SYMLINK: create a symbolic link to the device node." As Oracle Linux is derived from RHEL

this source is authoritative and corroborates that the comma implies an AND condition and that SYMLINK creates a link

leaving the original kernel name (/dev/hdb) intact.