Choosing a device name under /dev from the kernel command line

Question

I am booting CentOS via a USB install. The boot method is simply booting the ISO from GRUB2 installed on the USB Key.

The USB key always gets the "name" /dev/sda. Can I change that name from the kernel command line?

Just adding some info: When I boot Debian from an external USB hard-drive, that hard drive is labeled /dev/sdb, and the one inside the laptop is labeled /dev/sda. This really enhances my suspicion I can control the labels, but how ?

Answer 1

You are on the safe side if you ignore the device names (which might arbitrarily change) and identify the file systems by something more unique, eg. the label or UUID.

You can retrieve a list of the file system UUIDs and labels with

# blkid -o list -c /dev/null

You can access the device files in the directories

/dev/disk/by-label
/dev/disk/by-uuid

which are just symbolic links to the corresponding device files. If you wanto finer control what's going on, you should read about how udev works.

Answer 2

well sd is for removable scsi devices .. the a and the b's, etc .. {examples sda, sdb} are the equivalent to the concept of hda, and hdb, etc ...when different devices are plugged in, they are mapped to sda, sdb, etc .so if you plug some device it will be mapped to /dev/sda and then if you plug video camera it will map to /dev/sdb. And it is general that usb key getting name sda and in some computer it may get sdb also.