intrigeri:
> Hi,
>
> flapflap wrote (25 Jul 2015 23:51:45 GMT) :
>> So in this specific case it seems to work correctly (remains
>> write-protected).
>
> Well... my understanding is that in this case, the OS is obeying the
> indication the storage device is giving about being read-only.
> It's nice from a UX point-of-view, but it does not tell us much about
> how the storage device would react if the OS was *not* obeying this
> simple bit of information.
I'd guess that it simply lets you -o remount,rw the device (if initially
mounted -o ro), and then it's a normal writeable SD Card -- because it
actually/electrically is and the SD Card has no way to query the "lock
switch" status.
The case of USB sticks is a bit different since many of them have a
separate IC for doing the wear-leveling and USB interface and another
plain flash memory IC. And the latter usually has a write
protect/inhibit pin where it's possible to solder a switch to.
Just look for datasheets of parallel NAND Flash ICs for instance from
http://www.skhynix.com/
http://www.micron.com/
(sometimes they want you to register prior to downloading the datasheet,
in such cases just look at some electronics distributor like farnell.com
or digikey.com and download the datasheet from there)
