Minor Nodes and Minor Numbers

Drivers are allowed to manage their minor number name space. For example the sd driver needs to export 16 minor nodes (8 character, 8 block) to the file system for each disk. Each represents a different piece of the same disk, or a different interface to the same data (character/block). However, the driver still needs to be able to retrieve the instance number of the device in order to get soft state, and so forth.