Once next generation NVM arrives, the interface will change; that is a product implementation decision that is outside the scope of the SNIA NVM Programming Technical Working Group, Pappas said.
For example, one popular method that is already being used in multiple products today is connecting NVM directly to the PCI Express (PCIe) bus, which is usually directly connected to the processor.
Solid-state memory vendor Fusion-io is among more than a half dozen companies selling NAND flash PCIe cards for servers and storage arrays. The company has also been working on software development kits and hardware products that will eventually allow its NAND flash cards to be used as system memory and mass storage in the same way SNIA's specifications will for the industry at large.
Microsoft and Fusion-io have been working to develop APIs enabling SQL databases to use what Fusion-io calls its Virtual Storage Layer (VSL), which in turn allows developers to optimize applications for Fusion's ioMemory PCIe cards. Like any OS, SQL Server still uses NAND flash like spinning media, using a buffer and writing data twice to ensure resiliency.
Fusion-io calls its interface effort the Atomic Multi-block Writes API. The API is an extension to the MySQL InnoDB storage engine that eliminates the need for a buffer or redundant writes, giving the application direct access to -- and control of -- the NAND flash media.
"If we architect it to act like memory, and not like disk, we can do block I/O [reads and writes] and memory-based access," said Gary Orenstein, senior vice president of products at Fusion-io. "The APIs say to SQL, 'You have more capability than you think you have."
The result is a 30 percent to 40 percent improvement in SQL database performance, half the number of writes, and twice the life for the NAND flash because it is storing half of the data it typically would, Orenstein said.
"We're not saying flash will replace every instance of DRAM, but developers will have 10 times the capacity of DRAM at a little less performance and a fraction of the cost and power," Orenstein said.
Products using the Atomic Multi-block Writes API are expected within a year, Orenstein said.
How NVM has affected data centers
To understand the impact of NVM in a data center, it helps to look at what was there before it: hard drives and volatile system memory or DRAM. DRAM is extremely expensive and is volatile, meaning it loses all data when powered off unless it has a battery backup.
DRAM has about six orders of magnitude the performance of hard drives, or about one million times, according to Pappas. In 1987, when NAND flash entered the picture, it offered a middle ground with about three orders of magnitude better performance than of disk drives, or about 1,000 times faster, Pappas said. Until recently, however, flash was not cheap enough to use as a mass storage device in servers and arrays. Now that it is, its popularity is soaring.
Hardware manufacturers now use NAND flash as an additional tier of mass storage that provides faster performance for I/O-hungry applications such as online transaction processing and virtual desktop infrastructures. But NAND flash is typically not used as system memory, meaning a CPU does not access it as directly as it does DRAM memory.
Today, storage infrastructures are built based on the performance of hard disk drives. SNIA's efforts will promote an infrastructure that supports the type of performance that NVM can offer.