Originally Posted by rufius
Well its up to the udev system to decide. If it believes that /dev/sda exists currently in the system (even if its not really there), its going to mount as /dev/sdb. There's no sure-fire way to ensure that it'll always be one or the other unless are thorough in your proper umounting/mounting. Even then, its not guaranteed. What is your end goal?
Basically I am running Desktop with LIVE-CD, Whenever system boots up I would like to copy few files from USB to Livecd environment, then operate.
So whenever system boots up I am mounting the USB as /deev/sda1. Sometimes mount fails because USB is detected as /dev/sdb1, resulting failure in next execution also. So I want to make sure on what basis it OS decides it as /dev/sda1 or /dev/sdb1