It's a tragedy yeah, but it's not a catastrophe.
when they say "do a backup" it means on the internet, or in some media like CD-Roms, DVD... I'm sounding old aren't I? pen-drives?
I meant that there is active reading from the disk, when the controller is working in a heavily loaded mode and can fail. Which is what happened in my case. And the backup, also — yes, is done to another medium anyway. It doesn't matter if it's via the Internet or like me — usually to a nearby disk, but in this case I tried to upload to GitLab.
The old archives are still there because they are on another disk. It looks like I need to buy an HDD — it's more reliable, and in case of its death it's easier to get the information out.
Everything that could go wrong WILL go wrong.
-Murphy's law
Unfortunately, as practice shows, what can't go wrong, also goes wrong.