Other World Computing -- OWC -- has launched 750GB portable hard disk offerings spinning at 7200rpm. The Mac-based hardware sales company is shipping the OWC Mercury On-The-Go Pro drive in four connectivity options, offering the portable cases with USB 2.0, USB 3.0, a combo interface of USB 2.0 and FireWire 400 and a triple interface, with FireWire 800, 400 and USB 2.0. The 750GB hard disk can be purchased for internal installation as well.