When you define the number of disks on System p® and BladeCenter® JS hosts running the Linux® operating system, you are allocating space for configured disks. On the Linux operating system, disks are represented as device files.
There are 256 minor numbers that are available for each of the eight major numbers that can be used to define Linux device files.
(Number of major numbers) x (Number of minor numbers) / (Number of partitions) = Number of devices
For example, 8 x 256 / 16 = 128.