Hard disk drive medical monitor with mirrored HDDs

A medical monitor is disclosed for implantation in a human body for monitoring biological activity and states as detected by implanted sensors. The medical monitor includes a primary disk drive and a secondary disk drive, where the secondary disk drive mirrors the primary disk drive. An enclosure surrounds at least one of the primary and secondary drives. A transmitter and receiver for produces and transmits signals. The medical monitor is in communication with the sensors, by which information on biological activity and states is stored on the primary disk drive, and the secondary disk drive.