Secure scrub usage

The secure scrub image boots into an application that performs a disk
sanitisation routine on all disks found on the machine.  A user interface
allows one or more disks to be selected for scrubbing.  The up and down
arrow keys can be used to select a disk.  The disk can be selected for
scrubbing by pressing return or the space bar.  All disks can be selected
by pressing control-a.  Once all the candidates for scrubbing have been
selected exit the selection menu by pressing q.

When the selection menu is exited the scrubbing of the selected disks will
commence, the scrubbing of the disks is performed in 9 steps:

	1) write zeros
	2) read back to ensure all zeros
	3) write all ones (0xFF)
	4) read back to ensure all ones
	5) write 0x55
	6) read back to ensure all 0x55
	7) write 0xAA
	8) read back to ensure all 0xAA
	9) write random data

All reads and writes are to the full reported capacity of the disk being
scrubbed.

The status report page can be refreshed using the F5 key.  Once all disks
are scrubbed the status page will remain to indicate the results of the
scrub.  The secure scrubber can be exited by pressing the F7 key, in this
image that will result in the machine being powered off.