hdc

Самому интересно стало и нашёл (надеюсь) в каком направлении копать.
man devfsd.conf

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This runs the partx command to tell the kernel about  the  partitioning
       of  an IDE or SCSI hard disk when one of the partitions is accessed for
       the first time.  Notice the use of regular expression substituation  in
       the  command "\1", corresponding to the first set of parentheses in the
       regular expression being matched.

       LOOKUP                           ^((ide|scsi)/host[0-9]+/bus[0-9]+/tar-
       get[0-9]+/lun[0-9]+)/part[0-9]+$           EXECUTE    /sbin/partx    -a
       $mntpnt/\1/disc
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