On Tue, 22 Dec 2009, Hadmut Danisch wrote: > That particular usb pendrive was working for some time on my main > desktop computer. I had created an encrypted device (without partition > table, directly onto /dev/sdx) and put an ext3 filesystem inside. I > could write some amount of data (some months ago) and then the file > system hung, but I didn't care much about. Some weeks later I tried to > create a new file system, and that's where the writing problems began. > > Now I had that particular writing problems with this USB pendrive on > five different computers, alle with the latest Ubuntu. An > mkfs.ext2 /dev/sdx failed on all machines the very same way. You didn't try mkdosfs, did you? > But then, when I used the pendrive in a Windows machine, I could easily > format and use it with Windows. So the pendrive definitely is not broken > - at least not completely. > > Surprisingly, after formatting it with Windows with a fat filesystem, it > worked on all those Ubuntu machines, now I can write the files (onto > fat). And now, the mkfs.ext2 /dev/sdx works as well (what did not > terminate formerly). And even the large file can now be copied onto the > stick. > > > > My guess is that the internal controller of the USB pendrive is somehow > incompatible with Linux, encryption or ext2 filesystem. It is known that > flash memory cards and drives have internal controllers that continuosly > replace memory segments with each other to have them worn down equally. > To do so, some of these controllers are able to "understand" dos/fat > filesystems and use them as part of their strategy. > > I assume that I ran that controller with an encrypted filesystem into > some error mode. Or hit some memory segments that are broken (it's a > 16GB drive), where reformatting with vfat remixed the page order of > those segments. That certainly is possible. > I am not sure whether this is a problem of the USB drive (or its > controller) or the Linux machine. I'd guess it's not a Linux problem. However the only way to be certain is to mess up the pendrive again in the same way and then see if a Linux computer can successfully reinstall a VFAT filesystem. If you don't want to bother with further testing, you can just close out the bug report. > Best regards (and merry Christmas) Merry Christmas to you. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
