USB pen drive is seen as a CD-ROM

Earl Parker II · 09-23-2006, 09:58 AM

I'm running Slackware 11.0 RC3 on an older Dell Dimension L667r. I have no problem mounting a SanDisk 512MB pen drive- however, Slackware considers it a CD-ROM drive (/dev/sr0 in dmesg) so I'm unable to write to it. Is there a way to get Linux to recognize this thing as a r/w device?

dive · 09-23-2006, 10:19 AM

I just spent the morning getting my new pen to work with automount. What is your /etc/fstab entry for the pen?

Also what does dmesg show after plugging in the pen?

Earl Parker II · 09-23-2006, 01:18 PM

My /etc/fstab entry is:

Code:

/dev/sr0  /mnt/sandisk  usbfs  noauto,rw  0   0

The entry in dmesg is:

Code:

Vendor: SanDisk   Model: U3 Cruzer Micro   Rev: 2.15
Type: CD-ROM                               ANSI SCSI revision: 02
Attached scsi CD_ROM sr0 as scsi1, channel 0, id 0, lun 1
sr0: scsi1 drive

dive · 09-23-2006, 01:26 PM

Do you have USB Mass Storage and SCSI Disk Support modules loaded or compiled into the kernel?

Earl Parker II · 09-23-2006, 02:33 PM

Indeed I do. In fact, much to my amazement, I seem to have gotten it working- here's what I did:

1. I'd forgotten that I'd been fooling around with a camera (another story) which was assigned to /dev/sda in /etc/fstab, so I got rid of that line just to see what would happen.

2. I rebooted and had this in dmesg:

Code:

Vendor: SanDisk   Model: U3 Cruzer Micro   Rev: 2.15
Type: Direct-Access                        ANSI SCSI revision: 02
Attached scsi removeable disk sda as scsi1, channel 0, id 0, lun 0
SCSI device sda: 9900865 512-byte hwr sectors (507MB)

3. Then I entered this line in /etc/fstab:

Code:

/dev/sda  /mnt/sandisk  usbfs  noauto,rw  0   0

4. Now I'm thinking that this drive is being seen as a hard drive (sda) so I decided to see if I could create a filesystem on it:

Code:

mke2fs -v -b 1024 /dev/sda

5. After creating the ext2 filesystem I changed the appropriate line in /etc/fstab to read:

Code:

/dev/sda  /mnt/sandisk  ext2  noauto,rw  0   0

6. I mounted the drive manually and was able to read/write with no problems at all. Apparently it's now seen as a SCSI hard drive.

Thank you, dive, for responding. I don't think I left any steps out but if you see a glaring ommission just let me know.

I'm certainl no Linux guru but I'll be glad to help anyone with this sort of thing if I can.

dive · 09-23-2006, 02:38 PM

I had to put rw,uid=dive to get mine to write, but if it works ok then that's good.

Now I've got to figure out what to do with portable a portable 1 gig of ram...

Earl Parker II · 09-23-2006, 02:45 PM

Can you define a 'portable 1 gig of RAM'? This is a new one on me...

dive · 09-23-2006, 02:53 PM

1GB usb memory stick

Earl Parker II · 09-23-2006, 03:00 PM

Thanks- hadn't a memory stick referred to that way before... BTW, I'm use the terms 'pen drive' and 'memory stick' interchangeably- am I incorrect?

dive · 09-23-2006, 03:03 PM

Yeah I think you can use either term + I think they can also be named jumpdrive or thumbdrive

Nylex · 09-23-2006, 05:51 PM

Quote:

Originally Posted by Earl Parker II

5. After creating the ext2 filesystem I changed the appropriate line in /etc/fstab to read:

Code:

/dev/sda  /mnt/sandisk  ext2  noauto,rw  0   0

Surely you should be mounting a partition, e.g. /dev/sda1? Run "fdisk -l" (that's a lowercase L, not number one) to see what partitions are on the device.

Earl Parker II · 09-24-2006, 12:11 AM

You're exactly right- it should have read:

Code:

/dev/sda1  /mnt/sandisk  ext2  noauto,rw  0   0

I apologize for the typo.

combatbob · 09-24-2006, 05:33 PM

Sep 24 15:14:01 localhost kernel: hub.c: new USB device 00:10.4-3, assigned address 2
Sep 24 15:14:01 localhost kernel: scsi2 : SCSI emulation for USB Mass Storage devices
Sep 24 15:14:01 localhost kernel: Vendor: Pretec Model: 512MB Gini Rev: 1.10
Sep 24 15:14:01 localhost kernel: Type: Direct-Access ANSI SCSI revision: 02
Sep 24 15:14:04 localhost usb.agent[2207]: usb-storage: already loaded
Sep 24 15:14:57 localhost net.agent[2240]: Bad NET invocation: $INTERFACE is not set

Okay where do I go from here to mount this. acording to fstab usbfs is mounting in /proc/bus/usb possibly device usb-storage-1. but I can't access it. what do i need to do now. Kernel recognizes plug unplug states. howevere note the usb-storage already loaded message.. any hellp would be appreciated

dive · 09-25-2006, 04:03 AM

Have a look in kernel config under scsi devices for extra modules that you need for usb storage. You need SCSI Disk Support ( BLK_DEV_SD ) but there may be another. I have that and SCSI Generic Support ( CHR_DEV_SG )

You need to have at least BLK_DEV_SD compiled in or as a module. If as a module you can modprobe it to load it.

After installing the module you should get a line in dmesg to which device it's assigned. Mine says

Code:

sb-storage: device found at 3
usb-storage: waiting for device to settle before scanning
  Vendor: Samsung   Model: Mighty Drive      Rev: PMAP
  Type:   Direct-Access                      ANSI SCSI revision: 00
SCSI device sda: 2030592 512-byte hdwr sectors (1040 MB)
sda: Write Protect is off
sda: Mode Sense: 23 00 00 00
sda: assuming drive cache: write through
SCSI device sda: 2030592 512-byte hdwr sectors (1040 MB)
sda: Write Protect is off
sda: Mode Sense: 23 00 00 00
sda: assuming drive cache: write through
 sda: sda1
sd 0:0:0:0: Attached scsi removable disk sda

So the device is attached at sda1. Notice it waits a bit before it assigns a device to it. This takes a few seconds on my system so you need to run dmesg a few times until it gets attached.

combatbob · 10-04-2006, 09:45 AM

Sigh still no luck, any suggestions? I don't understand the Debian system. the pen drive doesn't come up under SDA as it did in slack and mandriva. It is there though. Cant edit or find scsi devices. I can't find any device under scsi. I might need to load a "package from Debian" to get it under scsi. I notice that NET failed. I was looking to see inf netsmnp was installed, it was an issue for slack. Blk_DV_SD looks like a variable, what lib or program is it associated with? Its starting to look like Debian loads the kernel then mouses all mods after that. I don't know for sure.