From what I understand (very roughly) with ZFS or BTRFS at least it takes one flipped bit in the particular block of memory which has just been successfully checksummed and 'approved' by the filesystem as valid for a write operation. Those are quite a few hoops to jump through so let's not head towards melodrama just yet.

That’s fine but most of us are running on NTFS, HFS+ or ext4 where it matters.

And then there’s the same problem with MLC SSDs which are just arrays of capacitors encoding that state as different charge potentials. As a former EE, capacitors leak regardless of implementation.

In 20+ years that bit eluded me...

dram cells used to be bigger.

Yes. Exactly.

Also SSDs scare me more. MLC disks have so many states stored in a capacitor that is trusted not to leak over the lifetime of the device. All it takes is a few electrons to go walkies and it’s game over.

As far as you know.

You make it sound like filesystems are so vulnerable. They aren't.

The chances of memory failure ruining data are extremely slim; lower than for hardware failure. If you care about your data, back it up.

Backups don't do anything if the original material contains the flipped bits.

I ran a lab notebook in word for a number of years and the document got fried by a filesystem error. The backup was toasted as well. This was corruption which broke the stage machine or parser in word which acted as a damage amplification.

As for the source of the error, we can only speculate but the possibility of a flipped bit is higher than you think.

Try running memtest86 on a PC without ECC for a week. You will be surprised at the results. I’ve seen perhaps 3 or 4 failures of this in new hardware. DRAM is not perfect.