Heart valve operation is assessed with patient-specific medical diagnostic imaging data. The playyard accessory unit includes an accessory frame and a case coupled to the accessory frame, and further includes a changer shell coupled to an upper pedestal section that is coupled to the playyard. In general, the present invention comprises a base section, conical section, terminal support section, and corresponding center terminal. The HOLDE mechanism is preferably implemented directly in hardware in the SATA link layer state machines within the host and the hard disk drive. Users are also prompted to select their particular point or zone within their known special image, which is displayed, among a jumble of other images, by the computer system requesting authorization, such display serving to authenticate the computer system to the user.