Discussed here last month: <a href="http://news.ycombinator.com/item?id=1282513" rel="nofollow">http://news.ycombinator.com/item?id=1282513</a><p>In short: the disks are needed to hold multi-page scans - think collating multiple copies, double-sided printing, etc. The problem is that normal file-system deletion is not a secure wipe, and files can be recovered with simple tools.