Get ready for quantum leaps in SSD capacity and performance
Speed equal to DRAM and capacity comparable to hard disks might be just a few years away.
It shouldn't surprise you that there's a tremendous amount of R&D going on in the solid-state drive (SSD) market. With SSDs pushing into every direction of computing, from servers to smartphones, it makes sense memory makers would be pushing for the next big breakthrough in NAND flash technology.
In the space of one week, we got two such breakthroughs. Diablo Technologies announced its Memory Channel Storage (MCS) architecture that allows flash storage components to plug directly into the memory channel normally used by the CPU and memory to communicate. Diablo believes that MCS can reduce latencies by more than 85 percent compared with PCI Express, currently the fastest interface for SSD drives.
Meanwhile, Samsung has announced the first 3D Vertical NAND (V-NAND) flash memory, in which memory is stacked in layers rather than horizontally. V-NAND uses a different kind of gate technology that cuts down on cell-to-cell interference that makes it difficult to scale this kind of flash memory. Samsung estimates that it can stack up to 24 layers of memory this way.
With this technology, Samsung can create a 16GB chip in a single layer, and with 24 layers of storage, that's 384GB in your smartphone, in one chip about the same size as standard NAND flash today.
So we have capacity and we have speed, but from two different companies. The question is whether they could ever be joined. If they are, it will likely be in a server, because the MCS architecture uses the DDR3 memory slots in a server and I cannot see these types of SSD drives being affordable to the masses any time soon. So a flash drive made with MCS would have to be plugged into a DDR3 slot with a few lines added to the BIOS by the server maker to recognize it.
Samsung is in business to sell its memory, so it will likely sell to a company making SSDs that fit into a DDR3 slot and using the Diablo MCS controller chip. That's great for servers. Smartphones? Not so much. Then again, they really don't need the drain on their battery.
The real benefit to the V-NAND is its durability. Samsung claims that the new memory layers in V-NAND improve reliability anywhere from two-fold to 10-fold, but also offer twice the write performance over conventional 10nm-class floating gate NAND flash memory.
That's very important all around, not just on servers, because write performance of flash has always lagged read performance, and doubts about the reliability and shelf life of the memory were what kept a lot of people away from SSD when it first came out. No one knew how long the flash would last before the cells wore out from constant reads and writes in a high I/O production environment and were reluctant to use flash.
Eventually that reliability and life span improved to the point you now see SSD as a standard offering in high-end file servers. The challenge for Diablo now is to increase density. A flash drive that would fit in a DDR3 slot would only be 200GB to 400GB. So who has high density memory? Why, Samsung.
Diablo said it expects to ship MCS controllers by the end of this year. Samsung did not disclose when it will ship the V-NAND although it has entered mass production of the technology.