This page contains a list of commands supported in DiskPart version 6.1.7600 - included in Windows 7. As far as I am aware all of the commands below are still supported. Click on the commands to see more detailed help information.
RECOVER- Refreshes the state of all disks in the selected pack. Attempts recovery on disks in the invalid pack, and resynchronizes mirrored volumes and RAID5 volumes that have stale plex or parity data.
REM - Does nothing. This is used to comment scripts.
REMOVE - Remove a drive letter or mount point assignment.
REPAIR - Repair a RAID-5 volume with a failed member.
RESCAN - Rescan the computer looking for disks and volumes.
RETAIN - Place a retained partition under a simple volume.
SAN - Display or set the SAN policy for the currently booted OS.