In a disk drive the drive motor and actuator are mounted in a drawer which is slidable to an open position in which there is no vertical obstruction over the motor. The removable cartridge can be placed on the motor with the motor extending into the cartridge to engage the hub. A shutter in an edge of the cartridge is moved to an open position when the drawer is closed to provide access for the actuator to move magnetic heads into read/write relationship with the disks. A lock for the shutter maintains it in the closed position when the drawer is open.