Winsor Crosby wrote:
> I thought it did more than that because of a couple of things. One of
> the reasons given for reformatting is to map around defects in the
> memory device. If there is a defect and reformatting is just an
> erasure then aren't you going to keep running into problems with the
> defect?
Modern disk drives have a defect table that is used to map out defects.
It's stored on a part of the disk not otherwise used for data or
directory. Maintenance and use of the table is a function of the drive
itself via the built-in drive controller. The OS knows nothing about
it. Whether CF cards have an equivalent facility I don't know but would
not be surprised since CF cards are, for all intents and purposes, EIDE
disk drives including a built-in drive controller. CF card controllers
also maintain a usage table to distribute "wear" across individual
sectors. I haven't seen stats on CF write cycle lifetimes in many years
but it used to be about 100,000 writes per sector. The wear tables
distribute the usage across all the sectors, ie; sector #1 is not always
in the same physical place. The built-in controller also used to be the
differentiator between CF and some other technologies like XD cards.
Whether XD cards have changed I don't know but it used to be that the
camera had to have the controller which meant the camera was
technologically limited on things like card size so you get to throw
away the camera instead of the card as the storage size grows. A dumb idea.
>
> Frequently advice is given to only reformat in the camera and not on
> the PC. If reformatting just does the equivalent of an erasure, that
> is, removing the directory information tags, then there is no point
> that I can see to reformatting in one device rather than another. The
> very real problems people have not reformatting in the camera would
> seem to indicate there is more going on than a mass erasure.
When the camera reformats it also adds a small set of folders unique to
the camera. Your PC knows nothing about them.
Chuck Norcutt
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