Linux uses logical labels for drives that are then mounted on the filesystem. These logical labels will vary depending on where the drives are mounted, meaning the same hard drive might have different labels at different times, depending on where and when it’s mounted.
When systems have more than one hard drive, Linux simply names them serially by incrementing the last letter in alphabetical order, so the first drive is sda, and the second drive is sdb, the third drive is sdc, and so on.