On Fri, 24 Dec 2004, lonblu wrote:
> > > -1- this pen physically contain 2 partition : one of 125MB and 1 of
> > > 1.44MB,but linux sees it the 125MB's one; I know linux can see it
> > > becouse I use to see it with a 2.4 kernel or the first versions of 2.6
> >
> > It's not surprising that Linux can see the 125 MB partition! Is your
> > problem that Linux fails to see the 1.44 MB partition? What does "fdisk
> > -l /dev/sda" reveal?
> fdisk -l /dev/sda
>
> Disk /dev/sda: 128 MB, 128450560 bytes
> 16 heads, 32 sectors/track, 490 cylinders
> Units = cylinders of 512 * 512 = 262144 bytes
>
> Device Boot Start End Blocks Id System
> /dev/sda1 * 1 490 125424 6 FAT16
That looks pretty clear. This device has only one partition, not two.
If you really want to be certain about it, do
dd if=/dev/sda bs=512 count=1 | hexdump
The partition table will show up in the last 66 bytes of data.
> > > -2- It is too slow: 2.24 minutes for transferring a 64MB file: I think
> > > it isn't using the 2.0 driver
> >
> > This would show up in your system log, especially if you turn on the USB
> > verbose debugging option in the kernel configuration. It would also show
> > up in /proc/bus/usb/devices.
>
> if I don't manually load ehci-hcd it is iniitially using 1.1 driver
Of course. The listing below shows that it _is_ running at 480 Mbps,
though.
> T: Bus=04 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=480 MxCh= 0
> D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
> P: Vendor=0d7d ProdID=1320 Rev= 0.50
> S: Manufacturer=
> S: Product=USB DISK Pro
> S: SerialNumber=073C16490085
> C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=200mA
> I: If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage
> E: Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
> E: Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
If the transfer remains slow, it might be because the device is generating
errors. If you turn on the usb-storage verbose debugging option in the
kernel configuration, maybe some error messages will show up in the system
log.
> > > -3- when I unplug and plug it back again and the directory of the mount
> > > point is open, the device sda1 change to sdb1 so I can't have a valid
> > > line in fstab
> >
> > Good grief, don't do that! You should never unplug a device containing a
> > mounted partition; it's likely to cause data loss and filesystem
> > corruption because of unwritten buffers. _Always_ try to unmount the
> > partition before you unplug.
>
> I use udev actually, and with supermount I never needed to umount partition
> first
I don't believe that for a moment. No matter what software you're
running, once the device is unplugged the compouter won't be able to write
out its dirty buffers. The only possible way to avoid problems is to make
sure there _are_ no dirty buffers, by using the "sync" option with mount,
for instance -- which reduces performance tremendously. Even with ext3
it's possible to encounter data loss if you unplug a device without
unmounting it first.
It's clear enough why the device name changed, though. The old name,
/dev/sda, was still in use because you hadn't unmounted the partition.
Alan Stern
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