Re: USB-Storage, slow speed with sync option

[Mark Lord <liml@rtr.ca>]

Lionel Bouton wrote:
> Mark Lord wrote the following on 14.09.2005 17:26 :
>> These flash sticks, along with CF and SD cards, all include
>> built-in controllers that do automatic wear-leveling.
> 
> Do they all have such controllers now? Last time I checked, low quality 
> parts didn't have them and it wasn't easy to verify which ones did.

Pretty much all of them use NAND flash, which comes with 1-3%
bad blocks from the factory.  So the onboard controllers already
have to deal with *that* issue, and the same remapping logic is
normally extended to allow them to do wear leveling as well.

Wear leveling is imperfect, in that they devices can only include
sectors *known* by the *device* to be inactive, so as files are
written and deleted many sectors are removed from the wear rotation
until the next time they are logically rewritten (or until a CFA ERASE
command, which Linux never does.  Sad.).

Cannot say for sure whether 100% of controllers are adequately intelligent,
but that kind of control logic is pretty pervasive these days.
It would be a very rare device indeed that lacks it.

Cheers