[no subject]

I think the best approach would be to catalogue the known protection
schemes and modify/expand whatever disk image file format is most
appropriate to handle each scheme. When more schemes are
discovered/documented, then the format is necessarily extended.

I don't think there's any other viable approach?

To go to the extremes of capturing the analogue data on the disk would
require not only, as mjd noted, hardware hacks and more sophisticated
software, but also a software 'emulation' right down to the analogue
behaviour of the disk controller/drive in order to be able to read (and
hence duplicate) the preserved images.

Regards,

-- 
Mark McDougall, Engineer
Virtual Logic Pty Ltd, <http://www.vl.com.au>
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266