What is "shell level" in secure delete?

[BBlakley]

I bought UltraSentry and it seems pretty nice. I think the help file is a little sparse - specifically, what is "shell level" in the security settings for secure delete?

[Macro]

If you check what the actual actions are in the configuration panel under the security tab, it could actually be consider higher security than the DoD Level D Erase, since it make two passes of the set of actions (fill 0xFF, fill 0x0, fill 0xff), where the DoD Level D makes one pass of the set of actions (fill 0xff, fill 0x0, fill random).
You may argue that the DoD last action (fill random) is better, but still two passes may be better then one... who knows.
Anyway for full HD erase nothing is better then the Secure Erase ATA command: it is even better then any DoD erase levels.