Just picking one at random: The Seagate Exos X20 series of hard disk drives is rated[1] with a MTBF of 2,500,000 hours. That's 285 years.

I don't expect anything with moving parts to last 1/10th that long, but MTBF is MTBF. :)

[1]: https://www.seagate.com/files/www-content/datasheets/pdfs/ex...

MTBF is for hardware failure, not data loss.

This recent study I found [1] shows almost 4% HDD loss after only 2.5 years for consumer hardware, enterprise products being a bit better.

[1] https://research.cs.wisc.edu/adsl/Publications/latent-sigmet...

If the data storage hardware cannot read a block that it has stored within itself, then has the hardware not failed?

Suppose I hired a scribe named Gunther, and this scribe named Gunther confidently states that he has a lifespan of a mean ~quarter-millennium. He can't really explain how he does it in simple terms, but Gunther states that he is an expert at transcribing and storing and retrieving records with great longevity and accuracy.

Gunther suggests that he can keep doing this for as long as he's around, give or take.

Two hundred years ago, I told Gunther to file a transcribe a 512-byte thing and to store it where he can find it upon my command for as long as he may live. Gunther did so with glee, and stored it however he did.

Today, 200 years hence: I ask Gunther to retrieve that 512-byte thing. But Gunther cannot do so; the 512-byte record is gone. Perhaps he can't retrieve it, or perhaps it has been destroyed, or perhaps it was stolen or maybe even something else. Maybe he can see the record, but the contents just don't make sense to Gunther anymore after all this time.

Gunther is very sorry about this.

Whatever it was: Only Gunther really knew where that block was stored, and Gunther was the only soul that had access to the area where it was stored, and Gunther is still very much alive to retrieve it. But Gunther still fails to retrieve it.

Gunther is a failure in this matter. It may have been a stupendous task, but Gunther failed it anyway. I place a mark on his failure record, and Gunther knows that he earned that mark of failure.

This marked failure affects Gunther's MTBF.

---

If Gunther is a hard drive, then: The hard drive now has a recorded failure.

(And in a pure and just world, we can chalk that failure up on the MTBF charts for everyone to see exactly what Gunther's MTBF has become.)

You could say so from a consumer perspective, but it is not what the MTBF you quoted measures. Read errors are not considered a hardware failure. Not an opinion.

That's a lot of work to avoid accepting your previous comment was incorrect.

I prepended that chapter with a question: If the data storage hardware cannot read a block that it has stored within itself, then has the hardware not failed?

I then presented practical examples of how I understand failures to behave in data storage devices, such as Gunther.

Can you answer the initial question?

Or are you just here to brow-beat your version of what you believe to be correct -- without the benefit of citation, or logic, or reason?

(Remember, kind HN user: I did not dismiss you at all. I engaged on all cylinders. And I'm here to learn. If you have something to teach, then: Please teach it. If not, then: Please disengage.

I'm not interested in logical fallacies, though, like appeals to authority: Those non-constructs waste our time.)

And MTBF is with active use. Electronics which are not powered on can last almost indefinitely and under a huge range of environmental conditions. From freezing cold to scorching heat.

You just need to make sure you let the electronics acclimatize before powering them on. I always let my external HD acclimatize for 24 hours before powering it on after I grab it from my shed where it's been lying for months in freezing conditions. No problem whatsoever.