Direct access to flash memory via PCI Express (see NVM Express: Flash At PCI Express Speeds) looks to replace disk-based interfaces like SATA and SAS (see What's The Difference Between SATA And NVMe?). Flash can utilize all the bandwidth of x8 PCI Express interfaces while single hard drives struggle to fill one lane. Arrays of hard drives can deliver higher bandwidth but they still suffer from access latency that is minute for flash storage.
NVM Express (NVMe) was all the rage at the Flash Memory Summit were companies related to the NVM Express Working Group were presenting papers on the technology. Companies like IDT and IP-Maker where showing NVME hardware and technology. IDT has a pair of NVMe bridge chips (Fig. 1) while IP-Maker provides IP that works with PCI Express interface IP. IDT's chips can be used for boards and drives while IP-Maker's solution allows integration into custom controller chips.
The University of New Hampshire Interoperability Laboratory has been set up to check out the Linux and Windows drivers and interoperability between devices and systems. They have an open source NVMe Compliance Suite. They have also been using LeCroy's Protocol Analyzer that has been enhanced to decode the NVMe protocol.
Figure 1. IDT's enterprise flash controllers provide an NVMe bridge to flash memory.
IDT's 89HF32P08AG3 (Fig. 2) supports a PCIe x8 Gen 3 interface and up to 32 independent 8-bit channels of NAND flash memory. It has a 4 Tbyte capacity when used with 64 Gbit flash chips. The 89HF16P04AG3 targets the lower end of the spectrum with a x4 PCIe Gen 3 interface and support for up to 16-channels. It has a 2 Tbyte capacity.
An option ROM allows the controllers to be used as a PCIe boot device. Both support 256-bit AES encryption. The DDR3 DRAM can be backed via a supercap allowing cached data to be written to flash in the event of a power failure.
Figure 2. IDT's NVMe reference design highlights a NVMe PCIe x8 board.
The chips support SLC, MLC and the new Enterprise MLC flash using either Toggle or ONFI interfaces. The IDT 89HF16P04AG3 and 89HF32P08AG3 are available in 27mm by 27mm FCBGA and 40mm by 40mm FCBGA, respectively (Fig. 3).
Figure 3. IDT's 16- and 32-channel NVMe enterprise flash controllers connect to PCIe x4 and x8 Gen 3 interfaces.
NVMe looks to make a major impact on the delivery of NAND flash memory in the enterprise and commercial space. The common NMVe drivers are available for all major platforms. IDT's chips move the bandwidth limit to the PCI Express interface providing a dramatic increase in radom I/O operations per second (IOPS) compared to SATA or SAS drives. Expect the chips to show up in drives and modules supporting the SSD (Solid State Drive) Form Factor Working Group specification. The connector supports SATA, SAS and PCI Express/NVMe.
