Re: [gentoo-user] e2fsck -a /dev/sdb1

[Mick]

On Thursday 15 Jun 2017 15:47:03 Rich Freeman wrote:

> You're comparing a 500kV breaker at a substation to a USB device?
>
> I'm very skeptical of the claim that any electrical effects associated
> with unplugging a device is going to cause issues with any USB device.
> They're basically designed to be hot swapped.

The comparison was made tongue-in-cheek to illustrate the point.  I don't know 
what the probabilities are but on at least two occasions I ended up with a USB 
stick which had a large number of bad blocks and partially destroyed files.  
This was a relatively young, but cheap USB stick.  The I/O errors were quite 
high and over-writing the blocks with zeros did not fix the problem.  I've 
come across this problem on two different USB sticks, probably because I was 
the go to guy for recovering data in an office full of MSWindows PCs.


> I'd also buy the argument that some poorly designed USB drives could
> end up with data loss to something other than the block being
> immediately written, but honestly I'm skeptical that this is a
> widespread problem.

Losing the odd files because of unplugging a USB stick during a write 
operation is a regular occurrence.  Ending up with large numbers of bad blocks 
is a rare phenomenon in my experience.  I blamed the problem on cheap USB 
sticks not being able to cope with the enthusiastic unplugging they were 
submitted to, which caused semiconductor breakdown or damage to the USB 
controller chip.  At the time I thought the wear levelling chip went sideways 
and was no longer able to re-allocate sectors.  Attempts to fix the bad blocks 
were unreliable and after some time using smartctl and dd to zero badblocks I 
gave up.
-- 
Regards,
Mick