Two methods of storing data on computers are popular today, and both have their advantages. The NAND flash used on SSDs is both fast and small. Since flash memory uses semiconductors for storage, SSDs look more like the RAM on your motherboard than the mechanical hard disk. However, SSD drives are expensive and capacities are still relatively low. Hard disk drives, which use a high-speed motor to access information stored on a magnetic disk, are less costly but are also lower-performance.
IBM’s Almaden Research Center has developed storage-class memory (SCM), a hybrid of flash and hard disk technology (IBM claims) in which solid-state drives are arranged in an array and accessed in a way similar to a magnetic drive instead of the usual single-flash chip you find in a USB flash drive. Each solid-state component would purportedly last longer and operate faster than magnetic media.
“A storage-class memory device would require a solid-state nonvolatile memory technology that could be manufactured at an extremely high effective areal density using some combination of sublithographic patterning techniques, multiple bits per cell, and multiple layers of devices,” says IBM researcher Geoffrey Burr. “Using SCM as a disk drive replacement, storage system products would be able to offer orders of magnitude better random and sequential I/O performance than comparable disk-based systems, yet SCM would require far less space and power in the data center. However, the success of SCM depends critically on its cost, and thus on the attainment of ultra-high densities--higher than current 2-bit Multi-Level Cell NAND flash--which is where our current research and development is focused.”
With storage class memory, an array of solid state disks is arranged in a similar fashion to how magnetic platters used to be stacked on hard drives (many drives are now on a single platter), but accessed directly as a semiconductor chip instead of by rotating the platter.