When One SSD Is Actually Four
Intel's block diagram makes clear how the SSD 910 comes together. From left to right, you have the physical PCI Express interface, the logic that facilitates communication between the PCIe bus and SAS, a multitude of SAS-based controllers, and the NAND flash itself, attached via an ONFi 2.0 interface.
In this exploded view, it's easy to see how the SSD 910 is built. Modularity is important here, as you can see from the NAND-laden daughtercards stacked on the main PCB.
That main controller board, which hosts the eight-lane, second-gen PCIe edge connector, is the brains of the operation. Under that silver heat sink, you'll find an LSISAS2008 PCIe-to-SAS controller. Armed with eight SAS 6Gb/s ports, the controller is capable of RAID 0, 1, 1E, and 10, though Intel's configuration doesn't facilitate hardware-based RAID support.
Instead, you're presented with either two or four unique volumes, depending on your version of the card. If you want to use the SSD 910 as a single, contiguous volume, it's necessary to create a software-based RAID setup.
The (positive) result is that there are no drivers to install or update. The LSISAS2008 has been on the market for quite a few years, and most modern operating systems support it natively.
LSI's PCIe-to-SAS hardware is flanked by four Intel EW29AA31AA1 controllers, pictured above, which were co-designed by Intel and Hitachi. Under them, you find DDR2 SDRAM cache chips from Micron. The controller board also hosts the interfaces used to attach the NAND daughterboards.
Each daughterboard contains 28 HET MLC NAND packages totaling 448 GB. Understandably, the second daughterboard is only utilized on the 800 GB version of Intel's drive, yielding 896 GB of flash.
The SSD 910 is not a bootable device. We know that's a blow to the aspirations of hardware PC enthusiasts, but Intel makes it very clear that this is a data center-oriented product. To that end, it's understandable that you'd never want your operating system and data together on the same drive. That's not a show-stopping feature for the SSD 910's target market. But it is a unique decision from Intel, considering that many of its competitors do support this.