Just for clarity, on the Windows side you're confusing the file system naming with the drive naming. Windows hides the drive naming from you almost completely, but you can see examples in the registry and if you edit your boot.ini file. A disk reference there might look like this:
You can also see individual disks in the disk manager tool. The reason I bring this up is that the ntfs file system allows you to play all kinds of games. You can mount a separate disk to a folder in your C: and another drive at the same time, and unmounted disks may not have a drive letter at all. So don't confuse the file system from disk naming.
Linux is similar, here. sda1 is a common partition name, but it could be mounted anywhere on the file system.