Saving Files to USB Drive

From Bootable Cluster CD

Determining Where the USB Drive is Located

Become Root

[bccd@host129]>su -

The password is letmein (or see the login splash screen for your image's root password).

Inserting the USB Drive

If you're at the console (text mode interface), you should see a lot of messages dumped to the screen, similar to the following:

Initializing USB Mass Storage driver...
usb.c: registered new driver usb-storage
scsi1 : SCSI emulation for USB Mass Storage devices
  Vendor: LEXAR     Model: JUMPDRIVE         Rev: 1.11
  Type:   Direct-Access                      ANSI SCSI revision: 02
Attached scsi removable disk sda at scsi1, channel 0, id 0, lun 0
SCSI device sda: 125952 512-byte hdwr sectors (64 MB)
sda: Write Protect is off
 /dev/scsi/host1/bus0/target0/lun0:<7>ldm_validate_partition_table(): Found an MS-DOS partition table, not a dynamic disk.
 p1
WARNING: USB Mass Storage data integrity not assured
USB Mass Storage device found at 2
USB Mass Storage support registered.

If you don't see these diagnostic messages, issuing dmesg should produce the same information. The BCCD uses hotplug to automatically register and load the drivers for common USB devices. Most commonly, your USB storage device is registered as a SCSI drive. You can see from the above, that the USB drive has been registered as /dev/sda.

Check the Partition Information

[root@host129:~]# fdisk -l /dev/sda

Disk /dev/sda: 64 MB, 64487424 bytes
4 heads, 32 sectors/track, 984 cylinders
Units = cylinders of 128 * 512 = 65536 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/sda1   *         1       983     62896    6  FAT16

This disk has a FAT16, or DOS-style, partition on the first partition of the first scsi disk (sda1). That's all the information that you'll need.

Mounting the USB Drive

Make the "mount point" on a read-write area of the BCCD system:

mkdir /mnt/rw/usb

Finally, mount the USB drive, using the partition information you determined from above (here, sda1):

mount -t vfat -o uid=bccd /dev/sda1 /mnt/rw/usb

Releasing the USB Drive

WARNING: DO NOT PULL OUT YOUR USB DRIVE UNTIL YOU'VE UNMOUNTED THE PARTITION! You will surely damage any files that you thought that you copied over.

On a Unix-style system, drives that are mounted cannot be arbitrarilly removed. To free up your USB drive so that it can be ejected, you will need to do a few simple things:

Make sure that you are not currently navigating the mounted disk. A good way to do this is to issue cd from all of your shells, or pwd to make sure that you don't have /mnt/rw/usb (or where ever it may be mounted) as part of your current working directory.

Make sure that you don't have any programs running that have been started when you had the USB drive in your current working directory. This is uncommon, but can be frustrating when you can't seem to tell why your USB drive won't unmount. Once you have met these conditions, you need to unmount the disk partition.

[root@mocha:~]# umount /mnt/rw/usb

[Note that there is no "n" in umount. It's missing. If you find it, please let us know so that we can put it with the "e" that we found left out of /etc/resolv.conf]

That should do it! If there were no errors (similar to "device busy"), go ahead and pull your USB drive out.