Hi.
I've changed my thought / attitude / approach on this topic over the years. This is more of a follow-on to Dazed_75 comments on SR.
I use a frame/carrier system on most of my PC boxes. I try a lot of OSs, so I have a lot of disks -- PATA, SATA, SCSI.
I find myself not so interested in testing the drives per se, but in
maintaining them. To do that, I use
SpinRite. It's not free, and it's not cheap. It
does recognize Linux filesystems.
One boots SR from a CD and it offers you a choice of the disks that it discovers. Then, among the various modes, it processes the sectors and makes sure the
sector is readable and writable. It initially saves the content, then does its verification cycle, and then restores the data onto the sector. So it
refreshes the data, as the author says. You can read more about the details and theory at the website.
SpinRite is definitely not for everyone, but when you consider that all your stuff is on the disk, you want to be sure that 1) you have a backup (and that you have
tested the backup), and that 2) the sectors can be read successfully.
But -- even if SpinRite is not your cup of tea, I agree with kilgoretrout about the UBCD.
Best wishes ... cheers, makyo