Memory and storage units

From HP-SEE Wiki

Memory technologies

Phase Change Memory (PCM)

One of the more promising solid state memory technologies on the horizon is Phase Change Memory (PCM). PCM has the potential to write data faster than current DRAM chips by charging atoms within a crystal, and this can led that the technology might enable instantaneous computer boot-up.

At the atomic level, PCM stores data in a compound of germanium, antimony and tellurium. When a voltage is applied to the atoms, they change into an ordered crystal. The data can then be deleted by melting the crystalline substance. To read the information, a computer determines the electrical resistance of the material. An important attribute of phase change memory is that the technology is non-volatile. This means it does not require power to retain information like standard RAM offerings. Along with the possibility of replacing system memory, these chips might end up competing with NAND flash as well. Despite the benefits, PCM suffers from an inherent issue that has slowed its path to adoption. The biggest one is its write speed. Current DRAM technology can perform write operations within a 1-10 nanosecond window, which is faster than the time it takes for the germanium, antimony and tellurium compound in PCM to crystallize. Other crystalline compounds with faster reaction times have been researched, but they are not as stable as the current PCM design, slowly erasing themselves in low temperatures over time.