Samsung ES Tool warning

I thought I'd pass along the fruits of an unpleasant learning experience.

Over the years, I've used many manufacturer-supplied diagnostic programs. None
of them were destructive, whether from WD, IBM, Maxtor, etc. The Samsung
offering - called ES Tool - has broken from that tradition.

Thinking that the warning about possible data loss was, like all the other
diagnostic software, only relevant to obviously-destructive options in the
program (such as low-level formatting), I didn't perform a backup on a pair of
1TB Spinpoint drives before running the basic diagnostic function (turns out
file system errors were caused by a software bug, and the drives are fine).

It is not read-only. It does a simple write-verify test, without any
prompting (relying on the warning at the beginning of the program that data
"may" be lost), which overwrites the last 8MB of the drive.

A typical file system probably wouldn't even lose any data from this, since
nothing is likely to be written to the last 8MB of a modern drive. Unless you
did something radical like stripe the two drives together in Windows, which
means that the last 1MB of the drive contains a Veritas LVM database. Used to
contain, that is.

I didn't lose any data in the end, but I did lose a lot of time (short answer:
use dd in Linux to back up the volume portion of each disc, recreate the
striped volume in Windows, then restore the backed up data with dd in Linux
again; fairly time consuming when you need to compress/decompress on the fly
across several drives because of the quantity of data).

So if you want to test a Samsung drive, back the data up first. Or at least
the last 8MB.