any device that has an electric motor can make sound. scanners and floppy drives use stepper motors to move the head with sensors that scan an image, or read or write, onto a magnetic disk. the faster the motor, the higher the pitch of the sound the motor makes. hard disks use a magnet and a coil to tilt the head. when voltage is supplied for long enough, the head speeds up and hits the bound, which makes the "drum hit” sound.