USB write problem where read is OK

Hi,

When I connect a USB external disk writing to it is not possible:

uri@uri-laptop:~>cp README /media/URI\'S\ DISK/PST/
cp: cannot create regular file `/media/URI\'S DISK/PST/README': Read-only file system

However copying from the USB is OK.

I looked a bit for solutions and installed pmount but no good.
I did not modify any file.

just as I verify this problem again, the problems looks a bit different:

suddnly the cp does work ( didnt do anything ) but now only the first file copy works and the others fail:
 dir PST contains 5 files:

uri@uri-laptop:~>cp -frp PST/ /media/URI\'S\ DISK/
cp: preserving times for `/media/URI\'S DISK/PST/backup 15 04 09.pst': Read-only file system
cp: cannot create regular file `/media/URI\'S DISK/PST/TI all 30 05 2009.pst': Read-only file system
cp: cannot create regular file `/media/URI\'S DISK/PST/outlook backup 27 04 09.pst': Read-only file system
cp: cannot create regular file `/media/URI\'S DISK/PST/z local flder.zip': Read-only file system
cp: cannot create regular file `/media/URI\'S DISK/PST/a0794638.pst': Read-only file system
cp: preserving times for `/media/URI\'S DISK/PST': Read-only file system

uri@uri-laptop:~>ls -l /media/URI\'S\ DISK/PST/*
-rwx------ 1 uri root 276317184 2009-06-21 03:36 /media/URI'S DISK/PST/backup 15 04 09.pst*

looks like after the first copy the USB goes to "Read-only file system" status.

sometime if I disconnects the USB and reconnect it the copying is always denied.

could someone please help me out?

thanks

Uri

Here is the output of commands that might be helpful:

sudo fdisk -l
cat /etc/fstab
ls -l /media*
dmesg | tail
mount
id

uri@uri-laptop:~>sudo fdisk -l
[sudo] password for uri:

Disk /dev/sda: 33.7 GB, 33732689920 bytes
255 heads, 63 sectors/track, 4101 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000591f3

   Device Boot Start End Blocks Id System
/dev/sda1 * 1 3962 31824733+ 83 Linux
/dev/sda2 3963 4101 1116517+ 5 Extended
/dev/sda5 3963 4101 1116486 82 Linux swap / Solaris

Disk /dev/sdb: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x8f9c798a

   Device Boot Start End Blocks Id System
/dev/sdb1 1 9729 78148161 c W95 FAT32 (LBA)
uri@uri-laptop:~>cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'vol_id --uuid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc defaults 0 0
# / was on /dev/sda1 during installation
UUID=3937874c-5394-4807-a9d5-c69f6f00b17d / ext3 relatime,errors=remount-ro 0 1
# swap was on /dev/sda5 during installation
UUID=63597962-5dfa-4b2e-988e-239ff11a3ee7 none swap sw 0 0
/dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0
/dev/fd0 /media/floppy0 auto rw,user,noauto,exec,utf8 0 0
uri@uri-laptop:~>ls -l /media*
total 40
lrwxrwxrwx 1 root root 6 2009-06-13 16:10 cdrom -> cdrom0/
drwxr-xr-x 2 root root 4096 2009-06-13 16:10 cdrom0/
lrwxrwxrwx 1 root root 7 2009-06-13 16:10 floppy -> floppy0/
drwxr-xr-x 2 root root 4096 2009-06-13 16:10 floppy0/
drwx------ 12 uri root 32768 1969-12-31 19:00 URI'S DISK/
uri@uri-laptop:~>dmesg | tail
[ 20.837833] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
[ 20.838980] NFSD: starting 90-second grace period
[ 22.909053] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 22.909067] Bluetooth: BNEP filters: protocol multicast
[ 22.941731] Bridge firewalling registered
[ 24.031520] Linux agpgart interface v0.103
[ 24.057421] [drm] Initialized drm 1.1.0 20060810
[ 24.153736] [drm] Initialized vboxvideo 1.0.0 20090303 on minor 0
[ 28.704056] eth0: link up, 100Mbps, full-duplex
[ 39.080199] eth0: no IPv6 routers present
uri@uri-laptop:~>mount
/dev/sda1 on / type ext3 (rw,relatime,errors=remount-ro)
tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
varrun on /var/run type tmpfs (rw,nosuid,mode=0755)
varlock on /var/lock type tmpfs (rw,noexec,nosuid,nodev,mode=1777)
udev on /dev type tmpfs (rw,mode=0755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
fusectl on /sys/fs/fuse/connections type fusectl (rw)
lrm on /lib/modules/2.6.28-11-generic/volatile type tmpfs (rw,mode=755)
securityfs on /sys/kernel/security type securityfs (rw)
nfsd on /proc/fs/nfsd type nfsd (rw)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)
gvfs-fuse-daemon on /home/uri/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=uri)
/dev/sdb1 on /media/URI'S DISK type vfat (rw,nosuid,nodev,uhelper=hal,shortname=mixed,uid=1000,utf8,umask=077,flush)
uri@uri-laptop:~>id
uid=1000(uri) gid=1000(uri) groups=4(adm),20(dialout),24(cdrom),46(plugdev),106(lpadmin),121(admin),122(sambashare),1000(uri)
uri@uri-laptop:~>