"Write protected" flash card

Skyhooker

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Hi, gang,

Because finding an affordable write-protected USB flash drive is so difficult these days, I bought an SDHC card and a mini USB card reader. I set the write-protect switch on the card to the "Lock" position, inserted it into the reader, plugged it in, and tested it out. All files copied to the card without hesitation. Huh??

Is there something I'm misunderstanding about the way a write-protected card works? Is it possible that the card reader overrode the lock? I emailed Transcend tech support this morning, but I'm still awaiting a reply, so I thought I'd see if you guys know something about this.

Thanks,


Sky
 
Sounds like the lock isn't working. I do the same thing, works fine (no writing when locked) here.
 
Well I remember from looking up the specs long ago for microcontroller projects that the lock really is more of a suggestion.

Found a simpler quote at Wikipedia

On the left side may be a write-protection notch. If this is present, the card cannot be written to. If the notch is covered by a sliding write protection tab, or absent, then the card is writeable. This can be overridden if the device reading it wishes to (and supports it).

Not all devices support write protection, which is an optional feature of the SD standard.
 
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