On Wed, Jul 27, 2011 at 02:38:19AM +0900, Round Robinjp wrote: > > I see. > The flash will then contain _random_ data in the non-used blocks. > That is not a problem, right? Nope. So long as the previously written (random) data on the card doesn't contain anything security sensitive. So for example, if someone used a microSD card to transfer credit card numbers from their e-commerce website to their credit card processor, and then afterwards, deciding they didn't need the card any more, and dropped it into a bin at the production line where it got flashed and put into a cell phone that was then shipped to Best Buy, then the non-used blocks wouldn't get written and credit card numbers might get exposed. But that's probably only something that folks who designed the security systems at Sony would do, so there's nothing to worry about. :-) > One more thing. > Although I have very small amount of files in my 4G image, > I see that the image has almost no zero-filled blocks. > Is that normal for ext4? It depends on how you created the image. > Can zerofree.c recognize them as non-used blocks? Yes, it uses the block allocation bitmaps to understand what is used and non-used. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
