The need for storing and accessing large amounts of data with the ease of being portable is apparent from the ubiquitous use of small form factor consumer electronics where demands for terabit per inch square areal densities is predicted. Conventional modes of data storage are reaching fundamental limitations on the areal densities achievable. Probe based data storage solutions, based on atomic force microscopy principles employ a force probe that has the resolution to image data at the atomic scale. Information is stored in the form of indentations that are a few square nanometers in area. Probe based high density data storage has the promise of delivering a few terabit per square inch densities in the near term. The dynamic mode probe based data storage platform will be developed under the proposal goals.
Intellectual Merit: A real-time model of the probe dynamics will be developed for high density data storage applications. The dynamic mode operation that leads to significantly smaller forces on the media and the probe will be employed as compared to the static mode operation that has been used in previous work. The fundamental tradeoff between the speed of reading the data and the resolution of the read data existing in current dynamic modes is overcome, leading to two orders increase in the detection speed. The physical modelling part of the proposal will provide an appropriate level abstraction of the forces appearing between the probe and media that remains tractable and is sufficient for data storage purposes. The communication system modelling and design objectives part will develop a communication channel model of the data storage system. Efficient and high performance detectors and error control codes will be developed for the system.
Broader impacts: The proposal objectives if achieved will directly impact the consumer electronics market and will provide a small form factor high density data storage alternative. Synergistic transfer of knowhow between the academia and industry by exchanging student visits and presenting specialized workshops will be achieved. A new course on probe based data storage that bridges the know how.
The need for storing and accessing large amounts of data with the ease of being portable has fuelled research in high density data storage devices. For instance, portable music players have higher storage capacities than desktop computers a few years ago. Conventional modes of data storage, such as magnetic or solid state devices employ physical principles that are reaching their fundamental limitation on the areal densities achievable. This research focused on a promising storage solution based on breakthroughs in nanotechnology. In particular, atomic force microscope (AFM) probe based high density data storage, that have the promise of delivering a few terabit per square inch densities were considered. The PIs investigated the dynamic mode operation where the AFM cantilever tip gently taps the medium. This mode is well known to have significantly better signal to noise ratios; however, it has traditionally been viewed as a rather slow technique. Thus, conventional ways of using the dynamic mode would result in unacceptable latency and delay in accessing a storage device. In this work the PIs show that in fact one can design detection techniques for the dynamic mode that are significantly faster. In particular, the following goals were achieved (i) Demonstrated detection techniques that were several orders of magnitude better than existing techniques on experimental obtained data, and (ii) showed the equivalence between the dynamic mode and a communications channel, thus establishing a bridge between different research communities. The proposed algorithms are currently being integrated into the hardware platform. The work supported mainly two graduate students and some others partially. In particular, students were trained on physical modeling, experimentation and signal processing. The students have graduated with their Ph.D.'s and are working in for high-tech companies, leveraging their training. The results of the research are being communicated to several companies such as IBM. Several journal papers and book chapters have resulted from this work and have helped disseminate our findings. The results of this work are likely to spur more interdisciplinary work at the intersection of nanotechnology and signal processing.
