IBM’s Memory Breakthrough Will Speed Up IoT and Machine Learning

IBM researchers have just revealed a new storage memory breakthrough that has the potential to speed up machine learning and access to the Internet of Things (IoT), as well as mobile phone apps and cloud storage.

For the first time, scientists have demonstrated reliably storing three bits of data per cell using a new memory technology known as phase-change memory (PCM).

While memory types span from DRAM to hard disk drives to flash, over the past few years, PCM has become quite popular in the industry as well, due to its combination of read/write speed, endurance, non-volatility and density.

The experimental multi-bit PCM chip used by IBM scientists is connected to a standard integrated circuit board.

For example, unlike DRAM, PCM doesn’t lose data when powered off, and it can endure at least 10 million write cycles, while an average flash USB stick tops out at 3,000 write cycles. 

Now IBM’s newest breakthrough will provide fast and easy storage to capture the exponential growth of data from mobile devices and the IoT.

Now that they are capable of storing three bits of data per cell, IBM scientists envision standalone PCM as well as hybrid applications that will combine PCM and flash storage together, with PCM as an extremely fast supply. So, for example, a mobile phone’s operating system could be stored in PCM, which would allow the phone to start up in just seconds, or entire databases could be stored in PCM for fast query processing in time-critical online applications like financial transactions.

Machine learning algorithms that use large datasets will also see a speed boost by reducing the latency overhead when reading the data between iterations.

Previous research conducted by IBM scientists and other researchers has resulted in the ability to store one bit per cell in PCM, so successfully storing three bits per cell in a 64k-cell array at elevated temperatures and after one million endurance cycles was a major success for the team.

“Phase change memory is the first instantiation of a universal memory with properties of both DRAM and flash, thus answering one of the grand challenges of our industry,” said Dr. Haris Pozidis, an author of the paper and the manager of non-volatile memory research at IBM Research–Zurich. “Reaching three bits per cell is a significant milestone because at this density the cost of PCM will be significantly less than DRAM and closer to flash.”

PCM materials exhibit two stable states, the amorphous and crystalline phases, of low and high electrical conductivity.

To store a ‘0’ or a ‘1’, also known as bits, on a PCM cell, a high or medium electrical current is applied to the material. A ‘0’ can be programmed to be written in the amorphous phase, or a ‘1’ in the crystalline phase, or vice versa. When it is time to read the bit back, a low voltage is applied—similar to how re-writable Blu-ray Discs store videos.

According to IBM, in order to achieve multi-bit storage, the scientists developed two innovative enabling technologies: a set of drift-immune cell-state metrics and drift-tolerant coding and detection schemes.

Their new technologies allow the cell state to be read reliably over long time periods after the memory is programmed, offering non-volatility.

“Combined these advancements address the key challenges of multi-bit PCM, including drift, variability, temperature sensitivity and endurance cycling,” said Dr. Evangelos Eleftheriou, IBM Fellow.