The state-of-the-art solid-state drives (SSDs) now heterogeneously integrate NAND Flash and dynamic random access memories (DRAMs) to partially hide the limitation of the nonvolatile memory technology. However, due to the increased request for storage density coupled with performance that positions the storage tier closer to the latency of the processing elements, NAND Flash are becoming a serious bottleneck. DRAM as well are a limitation in the SSD reliability due to their vulnerability to the power loss events. Several emerging memory technologies are candidate to replace them, namely the storage class memories. Phase change memories and magnetic memories fall into this category. In this work, we review both technologies from the perspective of their possible application in future disk drives, opening up new computation paradigms as well as improving the storage characteristics in terms of latency and reliability. © 1963-2012 IEEE.