The "millipede" high-density data storage system is based on micromechanical (MEMS*) components borrowed from atomic force microscopy (AFM). Tiny depressions created with an AFM tip in a polymer medium represent stored data bits that can then be read back by the same tip. Data written in this way can also be erased using the same tip, and the polymer medium can be reused thousands of times. This thermomechanical storage technique is capable of achieving data densities exceeding 1 Tb/inÃ‚Â², well beyond the expected limits of magnetic recording. Although the read-back rate of an individual probe is limited, high data rates can still be achieved by making use of massive parallelism. In our "millipede" system concept, an array consisting of thousands of thermomechanical probes operate in a highly parallel manner, with each individual probe capable of reading, writing and erasing data in its own small storage field. The read- and write-array can be fabricated in large quantities using wellestablished, low-cost semiconductor microfabrication techniques. *MEMS: Micro-electrical-mechanical system.