Linux won't recognise partition table but OS-X and M$ do

njbailey · 10-15-2006, 01:40 PM

I've got a Mustek PVR which was going cheap as I suspect it's discontinued: < GP£100 for a thing with a 40GB drive and an LCD screen on it. Trouble is, when plugging it into my Linux box, although it's claiming to use USB mass storage protocol, and dmesg says it's been attached at /dev/sdb, there's no way of mounting it. (In fact, dmesg contains the detection message twice, is this a clue??)

There is a statement in dmesg saying that it has an unknown partition table. fdisk runs, says there is one partition, but gives out loads of warnings about not ending on a cylinder boundary, nor even looking like a partition table. I'm running udev, so /dev/sdb1 doesn't even get created, but I tried mknod'ing an appropriate entry in /tmp for testing purposes, but of course no dice (not a valid block device -- no surprises there since the partition table wasn't recognised).

The big surprise comes plugging it into a Mac PowerBook. It mounts instantly and you get (interesting line at the end):

Code:

nick$ mount
/dev/disk0s9 on / (local, journaled)
devfs on /dev (local)
fdesc on /dev (union)
<volfs> on /.vol
automount -nsl [201] on /Network (automounted)
automount -fstab [205] on /automount/Servers (automounted)
automount -static [205] on /automount/static (automounted)
/dev/disk2s1 on /Volumes/Untitled (local, nodev, nosuid)

(the Mac calls drive <d> partition <p> disk<d>s<p>

So, what is it the Mac knows that Linux kernel 2.6.18 doesn't? Is there any way of getting the device mounted, perhaps by some explicit specification of the device partition table or geometry? My current fix involves making a SAMBA share on my linux box, then using my wife's Windows laptop which belongs to her employer to transfer the data, but this sucks

Thanks,

Debugging attempt follows...

Nick/.

Code:

polonius:/home/nick# fdisk -l

Disk /dev/sda: 36.7 GB, 36747104256 bytes
255 heads, 63 sectors/track, 4467 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1        1216     9767488+  83  Linux
/dev/sda2            1708        4467    22169700   83  Linux
/dev/sda3            1217        1707     3943957+  82  Linux swap / Solaris

Partition table entries are not in disk order
polonius:/home/nick# dmesg | tail -25
usb 2-3.1.1: new full speed USB device using ohci_hcd and address 6
usb 2-3.1.1: not running at top speed; connect to a high speed hub
usb 2-3.1.1: configuration #1 chosen from 1 choice
Initializing USB Mass Storage driver...
scsi2 : SCSI emulation for USB Mass Storage devices
usbcore: registered new driver usb-storage
USB Mass Storage support registered.
usb-storage: device found at 6
usb-storage: waiting for device to settle before scanning
  Vendor: PVR-2     Model: USB DEVICE        Rev: 1.00
  Type:   Direct-Access                      ANSI SCSI revision: 00
SCSI device sdb: 78140160 512-byte hdwr sectors (40008 MB)
sdb: Write Protect is off
sdb: Mode Sense: 20 00 00 00
sdb: assuming drive cache: write through
SCSI device sdb: 78140160 512-byte hdwr sectors (40008 MB)
sdb: Write Protect is off
sdb: Mode Sense: 20 00 00 00
sdb: assuming drive cache: write through
 sdb: unknown partition table
sd 2:0:0:0: Attached scsi removable disk sdb
  Vendor: PVR-2     Model: USB DEVICE        Rev: 1.00
  Type:   Direct-Access                      ANSI SCSI revision: 00
sd 2:0:0:1: Attached scsi removable disk sdc
usb-storage: device scan complete
polonius:/home/nick# fdisk /dev/sdc

Unable to open /dev/sdc
polonius:/home/nick# fdisk /dev/sdb

The number of cylinders for this disk is set to 9576.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): p

Disk /dev/sdb: 40.0 GB, 40007761920 bytes
255 heads, 32 sectors/track, 9576 cylinders
Units = cylinders of 8160 * 512 = 4177920 bytes

This doesn't look like a partition table
Probably you selected the wrong device.

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   ?           1        9576    39070035    6  FAT16
Partition 1 does not end on cylinder boundary.

Command (m for help): q

polonius:/home/nick#

stress_junkie · 10-15-2006, 06:54 PM

Try using Linux fdisk to create a new partition table.

njbailey · 10-16-2006, 01:02 AM

Writing a new partition table turns the thing into a paperweight: it won't even boot, saying "can't mount hdd" in the middle of the display... don't want to do that again (this is the second one). Fortuantely, it says "Mass Storage Capability" on the box, so I'm protected by the Sale of Goods act (it's "not of merchantable quality" if you're not even allowed to partition it, anyway, IANAL: I was nice to them and they sent me a replacement)

Can understand Window$ mounting it: MS are a law unto themselves. But how the heck does the Mac do it?

rkelsen · 10-16-2006, 02:28 AM

Are you running a custom kernel?

Do you have the correct 'partition type' support enabled?

njbailey · 10-16-2006, 08:11 AM

I'm running the kernel from Debian Sid, at the wrong computer right now but off hand it's 2.6.18-1-k7-smp. I've seen "partition type" threads on other forums when the "invalid partition type" comes up, but thought that as I'm on dual-processor wintel box hardware I'd be OK with consumer plug-in devices on that front.

How do I tell the partition type of the PVR? Could I dd the raw device (/dev/sdb) or something? or strings it?

Great idea though, keep 'em coming

Nick/.

njbailey · 10-17-2006, 04:38 PM

parted says it's msdos...

I've also found that the thing won't even display jpeg stills unless you use the windows app to convert them. Have checked the resolution, etc, used imagemagick v6 to convert them from larger source files.

It's looking like this machine's a bit of a crock as far as Linux is concerned.

Caveat emptor.

Nick/.

njbailey · 10-31-2006, 02:38 PM

Had a few spare hours so got a copy of qtparted to try and see what was going on.

Interesting.

/dev/sdd-1 [sic] free 0.01MB Start 0.03MB end 0.04MB
/dev/sdd1 fat32 Active 37.62GB Start 0.04MB end 37.26GB

And on the console you get:

nick@polonius:/home/export$ sudo qtparted
Error: The file system's CHS geometry is (4788, 255, 64), which is invalid.
The partition table's CHS geometry is (4864, 255, 63). If you select Ignore,
the file system's CHS geometry will be left unchanged. If you select Fix,
the file system's CHS geometry will be set to match the partition table's CHS
geometry.
Error: The file system's CHS geometry is (4788, 255, 64), which is invalid.
The partition table's CHS geometry is (4864, 255, 63). If you select Ignore,
the file system's CHS geometry will be left unchanged. If you select Fix,
the file system's CHS geometry will be set to match the partition table's CHS
geometry.

Not much you can do once it's told you that. Don't want to risk reformatting
it or rewriting the partition table, not after the last time!

Nick/.