Indilinx Everest 2: What’s New?
It’s been less than a half-year since the release of SSDs with the first-generation Everest controller, but the Everest 2, employed in the Vertex 4, is something more than just a revision. The second-generation Everest is dramatically different in everything, not only in its speed specs. To beat all other products available on the market, OCZ needed not just a fast SSD. Besides speed, users are interested in such important parameters as reliability and price, so the ideal SSD is supposed to offer an attractive combination of the three. Guided by OCZ, the Indilinx development team focused on introducing additional technologies to increase the service life of flash memory and improving error correction algorithms. The resulting Vertex 4 is absolutely different from the Octane.
That said, the foundation for all the improvements is the increased controller performance. The Everest was based on a 275MHz dual-core ARM processor whereas the Everest 2 clocks the same CPU core at 400 MHz. The developers have additionally improved the cache memory interface and algorithms and made the Everest 2 compatible with a larger DDR2/DDR3 buffer (up to 1 gigabyte). The cache buffer is utilized for both write and read operations because the new controller can perform data prefetching from flash memory. These enhancements ensure a twofold performance boost for I/O operations and 80% lower access latency.
So, the first and second Everest controllers are closely related. They are similar on the hardware level, the differences boiling down to higher clock rate and firmware optimizations. By the way, the hardware of the Indilinx controllers was originally based on technologies from OCZ's close partner Marvell, and the Everest 2 has much in common with Marvell’s highly promising 88SS9187 chip, but Indilinx did introduce a number of innovations on the hardware and software levels.
One of the most notable ones is Ndurance 2.0 technology which helps increase the service life of an SSD irrespective of the type of flash memory. Being an important feature of the new controller, Ndurance 2.0 allows OCZ to provide a 5-year warranty on its products based on the Everest 2. That’s equal to the longest warranty period you can get with consumer-class SSDs today.
There are four constituent parts of this technology. First, it’s an improved ECC algorithm that helps correct up to 128 data bits per each kilobyte. Second, it’s an adaptive program and read algorithm which takes into account the peculiarities of different NAND memory types and different manufacturers to adjust the internal voltage in such a way as to reduce flash memory wear. Third, data checksums are duplicated and distributed among different NAND devices. And fourth, write amplification is reduced by means of data pre-caching and per-block write combining.
Following the Vertex 4, the Everest 2 controller is going to give birth to a whole family of variegated products. Supporting 8 memory channels with 16-way interleave, it allows building SSDs with up to 1 terabyte capacity using existing NAND chips, and this maximum capacity may be doubled in the future. The controller is already compatible with upcoming NAND memory types (1x-nanometer tech process and TLC). Thus, the Everest 2 seems to have been designed for a long stay on the market.