The structure and organisation of a magnetic disk drive optimises the volumetric storage density within a device form factor by maximising the number of disks. The spindle and dual rotary actuators are supported at each end by a pair of support plates 22, 23 that are separated and supported by not only the spindle and actuator shafts, but also the voice coil motor core pieces and tie bars 52 which carry shock mounts. The head disk assembly 70 is shock mounted in the lower part 73 of a two part enclosure 72, 73 wherein the enclosure parts are aligned and separated by elastomer guides 77, 78 and the separation covered by a compliant tape 89 to complete the enclosure. Both actuators use a common servo surface while one actuator carries upwardly facing transducers and the other downwardly facing transducers so that each arm extending between disks 16 mounts only a single suspension-transducer assembly, thereby reducing the interdisk spacing. The enclosure occupies the entire vertical height of the form factor and the head-disk assembly occupies the full available height of the enclosure interior to accommodate as many disks as possible. Electrical components are excluded from the axial sides of the stack of disks.