SD card suddenly read-only

[Dotan Cohen]

2008/10/15 Emanoil Kotsev <deloptes at yahoo.com>:
> --- On Wed, 10/15/08, Dotan Cohen <dotancohen at gmail.com> wrote:
>
>> From: Dotan Cohen <dotancohen at gmail.com>
>> Subject: Re: SD card suddenly read-only
>> To: deloptes at yahoo.com, "Kubuntu Help and User Discussions" <kubuntu-users at lists.ubuntu.com>
>> Date: Wednesday, October 15, 2008, 10:24 AM
>> 2008/10/15 Emanoil Kotsev <deloptes at yahoo.com>:
>> >> Thanks. I've found that Windows machines are
>> picky
>> >> about USB storage
>> >> formated on Linux, especially when using UTF-8
>> filenames.
>> >>
>> >
>> > I don't remember that FAT has UTF support. There
>> for you specify it as mount option. The formatting has
>> nothing to do with it.
>> >
>> > Correct me if I'm wrong.
>> >
>>
>> That may be the problem, then. Hebrew Windows computers
>> format the
>> disk in such a way that I can move files with Hebrew
>> filenames safely
>> between systems. Linux does not.
>>
>
> Linux does if you tell it to. Read the vfat portion of 'man mount'
>
> [cite]
> (Note:  fat is not a separate filesystem, but a common part of the msdos, umsdos and vfat filesystems.)
>
> ...
>
>       codepage=value
>              Sets  the  codepage  for  converting  to  shortname  characters  on FAT and VFAT filesystems. By
>              default, codepage 437 is used.
>
> ...
>       conv=b[inary] / conv=t[ext] / conv=a[uto]
>              The fat file system can perform CRLF<-->NL (MS-DOS text format to UNIX text  format)  conversion
>              in the kernel. The following conversion modes are available:
>
>              binary no translation is performed.  This is the default.
>
>              text   CRLF<-->NL translation is performed on all files.
>
>              auto   CRLF<-->NL  translation  is  performed on all files that don't have a "well-known binary"
>                     extension. The list of known extensions can be found at the  beginning  of  fs/fat/misc.c
>                     (as of 2.0, the list is: exe, com, bin, app, sys, drv, ovl, ovr, obj, lib, dll, pif, arc,
>                     zip, lha, lzh, zoo, tar, z, arj, tz, taz, tzp, tpz, gz, tgz, deb, gif, bmp, tif, gl, jpg,
>                     pcx, tfm, vf, gf, pk, pxl, dvi).
>
>              Programs  that do computed lseeks won't like in-kernel text conversion.  Several people have had
>              their data ruined by this translation. Beware!
>
>              For file systems mounted in binary mode, a conversion tool (fromdos/todos) is available.
> ...
>
> iocharset=value
>              Character set to use for converting between 8 bit characters and 16 bit Unicode characters.  The
>              default is iso8859-1.  Long filenames are stored on disk in Unicode format.
> [cite]
>
> It is obvious that for hebrew the defaulted codepage and iocharset are not correct.
>
> Windows is the owner of the fat/vfat (fat32) filesystem, so they do it more elegantly ... but you have there only the msdos or ntfs filesystems as an option - this makes it a bit easier for them and for you.
> Linux supports a dozen of filesystems .... so it's a bit more complicated when the system has to know what to do with a drive when mounted.
>
> I am not that experienced in the field to tell you how to configure automount, but there is a way to let the system recognize your drive and mount with options suitable for it.
>
> since Linux supports ntfs write I prefer using this for portable drives as the fs is more mature and safe, when it comes to recover data.
>
> In your case I assume your hendheld can do only fat/vfat, so no choice. Just make the correct entry in your fstab file for this drive and I hope it will work forever
>
> regards
>

Thanks. I actually have read the manpage and come to the conclusion
that while I _could_ format the drive properly in Linux by careful
experimentation, and then mount it again on specific Linux computers
after fiddling with fstab, I simply prefer to format the drive on
Windows and have the advantage that it will work on any system with no
fiddling. A side advantage is that I save the time of experimentation.

Problem: I have not Windows computer! And the library machines do not
have admin access, which is needed to format disks. So I kindly asked
a student whom I do not know if I could format my drive on his laptop.
Problem solved!

-- 
Dotan Cohen

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