IBM’s Phase Change Memory

International Business Machines Corporation, commonly referred to as IBM, has recently unveiled an innovative new way to create a cheaper alternative to DRAM, as the company has been developing techniques to make enterprise data centers more dense. Designed to be less expensive than DRAM and faster than flash, phase-change memory, or PCM, is one of the several new emerging technologies. Phase-change memory has the potential to provide consumers as well as enterprises with faster access to data with lower costs; but prior to this happening, there are challenges which must be dealt with first.

One of these challenges is density, and the International Business Machines Corporation has said that they have achieved a new high in that area. The company has developed a version of phase-change memory which can host three bits on each cell. In 2011, the International Business Machines Corporation showed off a two-bit form of phase change memory; this three-bit form provides for 50% more density, allowing the International Business Machines Corporation to fully utilize the phase-change memory’s capacity, which still happens to be a pricey technology.

“PCM works by changing a glass-like substance from an amorphous to a crystalline form using an electrical charge. Like NAND flash, it keeps storing data when a device is turned off, which DRAM can’t do,” explains Stephen Lawson from Computer World. “But PCM responds to requests for data more quickly than flash: In less than one microsecond, compared with 70 microseconds, according to IBM. It also lasts longer than flash, for at least 10 million write cycles versus about 3,000 cycles for an average flash USB stick.

Phase-change memory has already been delivered in a few products, though on a relatively small scale. This small scale usage is due to the fact that phase-change memory remains to be more expensive than DRAM. At its current state, there has not been much reason to use phase-change memory, though this small scale iteration may possibly get the ball rolling to make phase-change memory a broader success.

“IBM added two features to make the new form of PCM possible. One is a way to adjust for so-called “drift,” which can gradually degrade the memory’s ability to store the right values. The other counters the effects of heat on PCM so it can run reliably in normal system temperatures,” Lawson added.