Darren New wrote:
> Invisible wrote:
>> Yeah, but AFAIK you only write to the superblock when you initially 
>> format the volume?
> 
> Hmmm... On FAT? I'm not sure. There might be a flag there that marks 
> whether the drive was dismounted cleanly or not. Or if you screw up the 
> root directory, I can see that mucking things up too. If there were just 
> a couple of directories, and the first sector of the root directory got 
> scrambled because she pulled it out while it was writing, I can see that 
> messing things up.

Yeah. Well it's not complaining the filesystem is broken, it claims that 
there *is* not filesystem at all. That's what I find so puzzling...

>> I can understand a file or folder being broken, but the entire FS?
> 
> FAT usually has two FATs, too, for just such a reason. It's possible she 
> got a warning that the first was broken and just ignored it until the 
> second got messed up too.
> 
> I'm not real sure of the electrical characteristics of a USB stick such 
> that it gets the whole chip messed up by being pulled out while writing, 
> but I have to believe avoiding that was one of the design goals.

As I understand it, to write to flash RAM, you erase a small block and 
then completely re-flash it. If that got interrupted, your whole block 
is gone.

No idea how large a flash block is - I'll bet it isn't the same size as 
a filesystem block! ;-)

You'd think a tiny little capacitor would keep the electronics running 
for enough split seconds to shutdown vaguely cleanly... *shrugs*

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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