Where did you get these from? I don’t know of any official format for Harmy’s work which is available in exactly 2 parts. As far as I am aware, whether in MKV, AVCHD or DVD5 format, they either come as a single file (torrent or download) or as a multi-part download (approx. 15-50 parts depending on the size).
Check the “ultimate introductory guide” in the first post of this thread for details.
Bluto