Root block

The root block is the second block of a QNX 4 partition.

It's structured as a standard directory and contains a label field and the inode information for these special files:

The files /.boot and /.altboot contain images of the operating system that can be loaded by the QNX bootstrap loader.

Normally, the QNX loader loads the OS image stored in the /.boot file. But if the /.altboot file isn't empty, you can load the image stored in it.