why is RW-mounted SD card treated as mounted RO?

[Robert P. J. Day]

On Fri, 14 May 2010, Nils Kassube wrote:

> Robert P. J. Day wrote:
> >   perhaps a simple solution to this, but i tossed an SD card into my
> > ubuntu 10.04 laptop, whereupon:
> >
> > $ mount
> > ... snip ...
> > /dev/sdb1 on /media/6458-0D98 type vfat
> > (rw,nosuid,nodev,uhelper=udisks,uid=1000,gid=1000,shortname=mixed,dma
> > sk=0077,utf8=1,flush) $
> >
> >   that normally suggests that the card is mounted read/write, but if
> > i "cd" onto the card and attempt to make any changes, i get:
> >
> > $ touch fred
> > touch: cannot touch `fred': Read-only file system
> > $
> >
> >   am i overlooking something obvious?  the SD card is unlocked, the
> > mount comment certainly suggests that the filesystem is writable, but
> > any attempt to modify the card contents fails (sudo makes no
> > difference, and that would generate a "permission denied" error,
> > anyway).
>
> Maybe you should check the filesystem. Unmount the it and then run
>
> sudo dosfsck /dev/sdb1
>
> in a terminal. See "man dosfsck" for more options.

  i finally gave up, copied the contents, reformatted as vfat, and
restored.  no problems now.

rday

-- 

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Robert P. J. Day                               Waterloo, Ontario, CANADA

            Linux Consulting, Training and Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Twitter:                                       http://twitter.com/rpjday
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