Following are the steps to manually mount a USB Mass Storage Device in RedHat Linux 7.1
(Kernel 2.4, KDE and GNOME sessions):

1. Plug in the device
2. Goto the Terminal window and make sure it is detected as a SCSI device by typing the
command "cat /proc/scsi/scsi". For example the Memory Stick Reader is seen as:

Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: OEI-USB Model: Memory Stick Rev: 0108
Type: Direct-Access ANSI SCSI revision: 02

3. Create a directory for the device at /root/mnt. For example, it can be /root/mnt/memstick
for Memory Stick.

4. Add this device to the file /etc/fstab in the following syntax:

/dev/sdnf mount-directory auto noauto,user 0 0

where

n - the device index (entered in sequence for each device at /proc/scsi/scsi file
as a, b, c, d etc respectively)
f - the partition number if it is a hard disk formatted device. Multi-partitioned
devices will have multiple entries. For floppy formatted media, this option is
not used (ie first device in /proc/scsi/scsi is entered as just /dev/sda).

For example, the entry for Memory Stick is:

/dev/sda1 /mnt/memstick auto noauto,user 0 0

5. Now, the device can be manually mounted using the command "mount mount-dir" from the
Terminal Window. For example, Memory Stick described above is mounted as

"mount /mnt/memstick".

The device can also be mounted from Desktop by right-clicking on the icon and choosing "Mount".
6. For multi-LUN devices, if the file /proc/scsi/scsi does not show all the LUNs,
the non-zero LUNs have to be attached to SCSI bus using the command:

echo "scsi add-single-device R C T L" > /proc/scsi/scsi

where

R - SCSI controller number (shown as scsi0, 1 etc in /proc/scsi/scsi file)
C - Channel number - always 0
T - Target number - always 0
L - LUN number

For example, when a 4-in-1 FlashToaster is plugged in, the entries in /proc/scsi/scsi will be:

Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: OEI-USB Model: MMC/SD Rev: 0104
Type: Direct-Access ANSI SCSI revision: 02

LUN 1 can be added to /proc/scsi/scsi, using the command,

echo "scsi add-single-device 0 0 0 1" > /proc/scsi/scsi

Now, the entries in /proc/scsi/scsi will be:

Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: OEI-USB Model: MMC/SD Rev: 0104
Type: Direct-Access ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 00 Lun: 01
Vendor: OEI-USB Model: SmartMedia Rev: 0104
Type: Direct-Access ANSI SCSI revision: 02

LUN 2 & LUN 3 can be added in the same way and mounted to give multiple icons.

Note:

1. If USB device is unplugged and replugged, the entries in /proc/scsi/scsi do not go away.
There will be ghost entries for the device. The new entries have to be used to mount the device again.
This also applies when the system is restarted since the SCSI sequence may vary after restart.

2. The device can also be manually mounted using the following command from the Terminal window
without changing the /etc/fstab file,

"mount -t auto /dev/sdnf mount-directory"

For example, Memory Stick described above is mounted as,

"mount -t auto /dev/sda1 /mnt/memstick".

In this method, you may not see the icon on the desktop. But the contents can be accessed from file manager.

3. Even if there is an entry in /etc/fstab, the device has to be mounted (Step 5 Only) after every restart.

4. Choose the "Unmount" option by right-clicking the icon to flush the cache before removing the
media.

5. Media change can be done by unmouting the current media and remounting the device after inserting
the new media.