This is a great idea.
Can I use seek on a raw device? The problem we run into if we're going to read the whole device, of course, is that the system (burly as it may be) does not have 4.5gb of ram, and 3.5gb of swap is unweildy. So we can't just slurp the whole disk in and checksum it... I was thinking that if we can read in the first gig and the last gig and provide two checksums, we can be reasonably assured that the middle 2.5 gig are okay.
Laziness, Impatience, Hubris, and Generosity.