Question about SMART and the life of a disk

[Menard]

Hello

I have an external USB Hard Disk (Back Up Plus Slim 500 GB - ST500LT012-1DG142) with Linux Mint on it (only the root) and its SMART had a #8 raw value at line 197 and line 198, and #3 at line 187 and HDTune had shown a red square in the middle of the first 20 GB, and now I made another SMART test and these values returned to #0 except the 187 that stays at #3
Is this frequent ? I didn't do nothing for this, I shoudn't be surprised if I had executed some tests or low level format but I only modified Linux Mint to be able to read the smart and then I accessed this SMART by the LM Tools, smartmontools and gssmartcontrol

nb : the line 5 show #0

I ve another problem with that disk but i ll make another subject, it is about line 193

[Menard]

In other words, do you see, great specialists, something like this, happening. Let it to say, a hard drive that get some pending sectors and then without doing anything special, it comes back to zero pending sectors.

In the meantime, it has been opened by Crystal Diskmark, HD Tune Pro (with surface scan) but no change in SMART after this ... then opened by Disks and then Gsmartcontrol under Linux, but I didn't proceed to tests

[labtech]

Modern hard drives are programmed internally to frequently Svan the disk surface for errors. This is why users hear drive activity when the drive is idle. It runs scans in the background.

So likely that is what your drive is doing. If it detects errors, adds them to the pending list, on the next verification cycle, if the block checks good, then it may move it out of the pending list, or it reallocates to the reallocate list if no good.

[fzabkar]

Hard drives perform background scanning. They can autonomously retest pending sectors and return them to service if they test good.

[Menard]

OK, it is clear now, thank you both very much for this clarification

Do you know when it started, because this HD is a ST500LT012 from 2014 ? A Seagate Back up plus slim
I use it for my root partitions of Linux Mint, it is old but only 600 startup

[fzabkar]

I think background scanning has been around for decades.