Re: ddrescue: detect repeated reads of the same data

[Matheus Afonso Martins Moreira]

Posting this on the list, I think I accidentally replied privately by mistake.

> Is this a Seagate drive in the Rosewood family?

It's certainly a Seagate HDD. Apparently it's in the Barracuda family.
Model number: ST2000LM015-2E81

> Sample of "moLD" sector:
>
> https://00289684175589411622.googlegroups.com/attach/3060916de6bc3/Screenshot%202023-09-03%20132510.png?part=0.1&view=1
>

That matches my output almost exactly. Just verified it,
ddrescue just keeps reading that over and over again.
At first it froze for quite a bit of time while the kernel
logged some I/O errors to the Linux console.
Then the I/O errors stop and ddrescue resumes
reading again, but that pattern is all it ever gets
back from the drive.

I assume the "moLD" is part of some kind of header?
I found these forum posts on the web about it:

https://www.recoveryforce.com/forums/viewtopic.php?t=595&start=10

Appears to be some kind of bad block pattern.

---

As I suspected, that's an SMR Rosewood model.

I don't know what causes this phenomenon, but it is well known in the
data recovery business.

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Wow. I've read that SMR drives were quite problematic.
I can't believe I was using one of these things all this time.

I assume the drive is pretty much dead then.
Tomorrow I'll get to work on restoring
everything ddrescue managed to get out.