work with USB flash disk in RH
 

How does RH detect a USB flask disk? HOw can I access this disk in RH?

Check dmesg | tail. Then, mkdir /mnt/flashdrive and mount what you found from dmesg there.

I can not do this. what is the command "dmesg | tail " mean?

dmesg is a console command that outputs the kernel ring buffer. tail is a utility that will print lines from the end of a file. You will need to start a terminal window and type the commands. The | is called a pipe. The output of the first command is sent as input to the second command.

If this USB flash drive is the only SCSI like device (includes SATA and Firewire) then its device ID will be /dev/sda. The output of the dmesg command should show that the device being recognized and automatically being assigned to /dev/sda.

What version RH are you running? You will need to create a directory to use as a mount point and then mount the device.