[Discuss] SSD: enterprise vs. consumer Flash

[tmetro+blu at gmail.com (Tom Metro)]

Edward Ned Harvey wrote:
> The flash they use in USB sticks and SD cards is the same flash they use in
> enterrpise hard drives.

Are you sure about that?

Elsewhere in this thread the different types of Flash - multi- (cheaper)
and single- (high-end) level Flash were mentioned.

Even if multi-level technology spans the low to mid-range parts, it
seems likely that the mid-range SSDs are going to be using higher
density chips, with faster write speeds, both of which will lead to
lower production yields and thus higher prices.


> But the controller from a USB fob, versus a commodity SSD controller,
> versus an enterprise SSD controller are wildly different, both in
> terms of performance and reliability.

What makes an enterprise SSD controller more reliable? Or are you saying
the controller itself isn't more reliable, but it implements hardware
wear-leveling algorithms that makes the overall SSD more reliable?


> Flash itself is dirt cheap.  What you're really buying is the on-device
> flash controller, that maps the flash blocks to virtual HDD blocks, and
> implements the USB/SATA operations.  

Are you sure about that?

The cost of semiconductors generally comes down to quantity of silicon
required (die size) and factors that impact yield. Greater complexity
increases the probability of a defect, and reduces yield. Similarly,
cutting edge speed requirements leads to the need to test and sort
parts, throwing out (or labeling with lower specs) the failing parts.
This is why high-end CPUs are expensive.

I would expect even in an enterprise SSD for the vast majority of the
silicon to still be devoted to the Flash storage chips themselves, and
the cost impact of the controller to be a minor (maybe 30%?) player.

Have you seen evidence to the contrary?

 -Tom

-- 
Tom Metro
Venture Logic, Newton, MA, USA
"Enterprise solutions through open source."
Professional Profile: http://tmetro.venturelogic.com/