Refactor the 'init' command to automatically calculate values.
Refactor the 'init' command to automatically calculate values.

Floppy disk devices are more predictable than hard disks. The most common type
of device now is the 3.5-inch device, and this is what is typically emulated for
most osdev. If this assumption proves to be wrong, then more distinct media types
can be added.

tjhancocks/imgtool