updated 03:35 pm EDT, Thu June 30, 2011
IBM working on fast 2-bit phase change memory
IBM, which turned 100 recently, on Thursday said it has developed solid-state chips that have the same capacity as current NAND flash storage but 100 times more performance and much longer durability. The so-called phase-change memory (PCM) chips have the ability to store two bits of data per cell without corrupting it, which is not something that could have been said of early versions of the technology. The nonvolatile memory retains data after its power supply is shut down, just like NAND flash memory.
A significant difference involves that PCM memory doesn't require existing data to be marked for deletion before new data is written to it. Such erase-write cycles slow down NAND performance and wear it out over time, with product cycles in the range of 5,000 to 10,000 in consumer products and as much as 100,000 in enterprise-class devices. IBM says its PCM memory has a lifecycle of 5 million write processes.
One possible application for PCM is as a repositor when paired with DRAM. Semi-actively used data can be moved to the DRAM when needed from PCM, increasing processing speeds. The CPU can alternately talk directly to the PCM.
PCM relies on electrical charges to change areas on a glassy material from crystalline to random or amorphous. Not only does this require less power than NAND flash, but is up to 100 times faster because it doesn't first require existing data to be marked for deletion.
Current IBM PCM circuits are a large 90 nanometers in size, which is roughly twice the width of the densest modern SLC PCM products, but this will be reduced with time.
The company doesn't plan to make consumer PCM products but rather license the tech to memory makers like Toshiba and Samsung. [via ComputerWorld]