Unlike most other filesystems like Ext2fs and JFFS2, which reside on top of the underlying block device, TMPFS sits directly on top of the VM. Thus mounting the TMPFS filesystem is a simple affair.

At this point, you have the initrd image in a block device suitable for mounting.

It is connected to the external mounting block by a coupling that compensates unavoidable misalignment between the scale and the machine guideways.