The gap is filled later in this chapter, in Section 3. Char devices are accessed through names in the filesystem. If you specify the -d flag, the mkdev command only defines the device. This flag is not compatible with the -d and -S flags. Not all devices support user-supplied names. This flag cannot be used with the -l flag unless the -c , -s , and -t flags are also used. Some major device numbers are statically assigned to the most common devices.

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This flag cannot be used with the -d and -S flags.

This flag cannot be used with the -d flag. Queue device names must begin with an alphabetic character.

makedev(3) – Linux manual page

Specifies the connection location, indi- cated by the -w ConnectionLocation ConnectionLocation kkdev, on the par- ent. If you do not use the -l flag, a name will be automatically generated and assigned. Defines the device in the Customized Devices object class.

The script can be adapted for another driver by redefining the variables and adjusting the mknod lines.

Linux World: The working of macros MAJOR,MINOR and MKDEV

The command to create a device node on a filesystem is mknod ; superuser privileges are required for this operation. Specifies the predefined device, indi- cated by the Name variable, in the Customized Devices object -l Name class when not used with the -c-sand -t linu.


With Safari, you learn the way you learn best. You can use any combination of the -c-sand -t flags needed to mkde identify the predefined device. Avoiding lengthy scripts is useful during development. Not all devices support this feature. Prevents the device from being set to the Available -S state. Related Information The chdev command, lsattr command, lsconn command, lsdev command, lsparent command, rmdev command. Specifies the device attribute value pairs to be used instead of the defaults.

Specifies the already defined device, indicated by the Name variable, in the Customized Devices object class when not used with the -c-sand -t flags.

Linux Device Drivers, Second Edition by Alessandro Rubini, Jonathan Corbet

Stay ahead with the world’s most comprehensive technology and business learning platform. For private drivers, we strongly suggest that you use dynamic m,dev to obtain your major device number, rather than choosing a number randomly from the ones that are currently free.

Some major device numbers are statically assigned to the most common devices. Not a Forum Member?

All Linux Man Pages. The default in our script is to give access to a group of users, but your needs may vary. If you are only loading and unloading mkde single driver, you can just use rmmod and insmod after the first time you create the special files with your script: Stopping this command before it is complete could result in a corrupted database.

If you use an -a flag with multiple attribute value pairs, the list of pairs must be enclosed in quotation marks with a blank space between the pairs.


When using the mkdev command, you can supply the flags either on the command line or from the specified File parameter. The last few lines of the script may seem obscure: Thus, while much of the groundwork has been laid for larger device numbers, they are mkxev treated as bit integers for now.

Overview in AIX Version 4. Only the root user and members of the sys- tem group should have execute x linix to this command. This flag cannot be used with the -d flag. The reason is that the script must be run by the superuser, so newly created special files are owned by root. The -a-pand -w flags cannot be used in this case.

If you do not specify either the -d flag or the -S flag, the mkdev command makes the device available. In addition, if your script is to be run at modev time, you will need to make a link to it from the appropriate run-level directory i. Removing a Driver from the System.