Project S.A.L.T.: A Roadmap for Exabyte-Scale Monolithic Diamond Archives

Abstract Humanity is generating data at a rate that is unsustainable for current archival technologies, which suffer from limited density and degradation within decades. We propose a new paradigm for permanent, ultra-high-density storage: the S.A.L.T. (Synchronous Asymmetric Linear Tuned) Monolithic Diamond Archive. This technology is based on a single, perfect diamond crystal where both the storage medium and the electronic assessor grid are a unified entity, fabricated via in-situ laser ablation and doping. Data inscription and readout are achieved through a revolutionary holographic acoustic method, allowing for a massively parallel, 3D readout of the entire data volume. This solid-state design eliminates thermal mismatch and is impervious to physical degradation, radiation, and extreme temperatures, creating a path to an exabyte-scale archive capable of preserving data for millennia. We present a phased, multi-decade roadmap, beginning with today's technology, to make this revolutionary storage system a reality.