It's been over 20 years since NAND flash was supposed to take over the world, so why is the 'ultra-portable' laptop I'm writing this on still using HDD? And why, nearly 30 years after the invention of flash, are we still debating its applications vs. the rotating platter? Given the performance advantages of flash and the mechanical shortcomings of HDD - things like wear and susceptibility to shock and vibration, not to mention the latency associated with spinning up for reads - it's no wonder that flash has long been the darling of memory technology futurists. So why after all this time has flash not replaced older technologies? I'll give you a hint: It's all about the money. But it's not only about the money - check out our list of five top barriers to flash adoption:
1. Cost - Despite years of oversupply in the flash market, and the corresponding reductions in price, flash is still relatively expensive when compared to HDD, especially on a $/bit basis. To make matters worse, the current economic climate has taken its toll on the flash industry, spurring several rounds of consolidation and requiring flash vendors to curb manufacturing costs by shrinking portfolios and closing fabs. Predictably, these changes in the supply landscape are causing prices rise in many cases, making the cost factor an even bigger problem for flash.
2. Shrinking lithography = lower endurance - One way for flash manufacturers to remain competitive is to use smaller die size to reduce raw material costs. Just a couple years ago, the vast majority of NAND flash was manufactured with 90nm lithography. Most vendors are now planning to move to 30nm technology either this year or next. An unfortunate side-effect of smaller lithography is significantly decreased endurance. SLC NAND, which had 100K + erase cycles, is now predicted to be in the 50-70k range. The biggest impact is on MLC NAND where the endurance has gone from 10k erase cycles to around 3k (a 70% reduction!).
3. Increasing ECC - Another side-effect of shrinking lithography is an increase in error rates for flash, requiring stronger correction codes. Most SLC NAND flash today requires 1-bit correction. That number is predicted to increase to 4-bit on 30nm NOR parts. And the ECC outlook for MLC NAND is even worse, requiring ECCs greater than 12-bit (compared to 4-bit or 8-bit today). These increased ECC requirements mean the controller design for managing flash will become more complicated, and more difficult for OEMs to implement. Performance will also be impacted, especially if the ECC is done in software running on the host processor.
4. Vendor volatility - Churn or volatility in the flash market, the products of a difficult economic climate, are making it difficult for OEMs to find a reliable source of flash parts. Examples are everywhere; A major flash supplier is currently under Chapter 11. There are merger talks happening between SanDisk and Samsung. Asian vendors have been hit especially hard, particularly those also in the DRAM business. OEMs are rightfully concerned about interruptions to their production cycles in the midst of all this turmoil.
5. Lack of killer application - While NAND flash densities have continued to increase, the industry is still waiting for the killer application to gobble up these immense quantities of flash. For long SSDs have been viewed as that application but they have not taken off as fast as the flash industry would have liked. In spite of the obstacles faced by the industry, flash remains a strong and growing choice for data storage and has put breakthrough devices like MP3 players and smart phones (iPhone!) into the hands of millions of consumers. Early adopters of SSD technology in laptop computers, netbooks and enterprise applications are making a solid case for mass market potential there, which should significantly drive flash adoption in the next few years. Visit the FlashFX Tera page to learn how Datalight is making flash easier and more competitive.