Hitachi on Wednesday announced the shipment of more than 25 million Travelstar Z-series, 7mm hard drives for notebooks, ultra-thins, Ultrabooks, and other portable form factors that support slim 2.5-inch storage devices. It's the sort of thing companies like to brag about, but rather than gloat over record shipment numbers, Hitachi spent the bulk of its press release talking about the 7mm form factor and its new 500GB Travelstar Z7K500 drive, supposedly the industry's fastest and highest capacity single-disk 7200RPM hard drive.