MEMS (micro-electric-mechanical-systems) probe storage devices. These devices are not solid state. Instead, a very small platter coated in chalcogenide is dragged beneath thousands or even millions of electrical probes that can read and write the chalcogenide. Hewlett-Packard's micro-mover technology can accurately position the platter to 3 nm so densities of more than 1 Tbit (125 GB) per square inch will be possible if the technology can be perfected. The basic idea is to reduce the amount of wiring needed on-chip; instead of wiring every cell, the cells are placed closer together and read by current passing through the MEMS probes, acting like wires. This approach bears much resemblance to IBM's Millipede technology. Samsung 46.7 nm cell In September 2006, Samsung announced a prototype 512 Mb (64 MB) device using diode switches. The announcement was something of a surprise, and it was especially notable for its fairly high memory density. The prototype featured a cell size of only 46.7 nm, smaller than commercial flash devices available at the time. Although flash devices of higher capacity were available (64 Gb, or 8 GB, was just coming to market), other technologies competing to replace flash in general offered lower densities (larger cell sizes). The only production MRAM and FeRAM devices are only 4 Mb, for example. The high density of Samsung's prototype PRAM device suggested it could be a viable flash competitor, and not limited to niche roles as other devices have been. PRAM appeared to be particularly attractive as a potential replacement for NOR flash, where device capacities typically lag behind those of NAND flash devices. State-of-the-art capacities on NAND passed 512 Mb some time ago. NOR flash offers similar densities to Samsung's PRAM prototype and already offers bit addressability (unlike NAND where memory is accessed in banks of many bytes at a time). Intel's PRAM device Samsung's announcement was followed by one from Intel and STMicroelectronics, who demonstrated their own PRAM devices at the 2006 Intel Developer Forum in October. They showed a 128 Mb part that began manufacture at STMicroelectronics's research lab in Agrate, Italy. Intel stated that the devices were strictly proof-of-concept. BAE device PRAM is also a promising technology in the military and aerospace industries where radiation effects make the use of standard non-volatile memories such as flash impractical. PRAM devices have been introduced by BAE Systems, referred to as C-RAM, claiming excellent radiation tolerance (rad-hard) and latchup