Ultrahigh storage densities of up to 1 Tb/in.2 or more can be achieved by using local-probe techniques to write, read back, and erase data in very thin polymer films. The thermomechanical scanning-probe-based data-storage concept called Millipede combines ultrahigh density, small form factor, and high data rate. After illustrating the principles of operation of the Millipede, a channel model for the analysis of the readback process is introduced, and analytical results are compared with experimental data. Furthermore, the arrangement of data-storage fields as well as dedicated fields for servo and timing control is discussed, and system aspects related to the readback process, multiplexing, synchronization, and position-error-signal generation for tracking are introduced. Finally, the application of (d,k) modulation coding as a means to further increase areal density is presented, and the effect on the user data rates discussed.