* Sony's MiniDisc stores music on a tiny 64mm optical disc that can be used and re-used like a floppy disk. Now, Sony has enhanced the format so that it can be used for storing PC data as well. The HD-MD format uses new high-capacity discs of 1Gb. Sony says HD-MD has been developed for the broadband era and uses the same File Allocation Table (Fat) system as a PC, allowing a variety of data files to be stored on a blank HD-MD disc. HD-MD equipment connects to a PC via a USB port.