CDFS, Compact Disc File System aka ISO 9660
or the somewhat different Linux virtual file system CDfs that allows access to individual tracks on a CDDA disc?
I don't believe either is possible on a Hard drive.
And in any case would not disallow "initialization" and subsequent formatting of the drive.
I have a WD 1.5TB drive that ran for about a month... formatted NTFS
(on a Windows 7 system), no data written to it... connected to an XP
system via eSATA, the day when data was attempted to be written to it,
when it became unresponsive...
connecting it to another (windows 7 system) the drive triggered an "uninitialized drive" response from Windows during which the drive would not initialize.
If you can't initialize it you obviously cannot format it.
knowing a work-around would be interesting, but frankly if it will
not initialize or format Western Digital can send me another one, it's under warranty.