Failure-Tolerant SSDs

Summary

Parallel-transfer Solid State Disks (pSSDs) have a variable level of automatic, built-in backup and contain a number of NAND Flash chips and a custom controller chip as components.

N Flash chips in a pSSD are written and read simultaneously. 

• • pSSDs solve the limited number of write cycles problem which has prevented NAND Flash from replacing Hard Disk Drives (HDDs).  pSSDs solve that problem by allowing multiple Flash chips to fail without the loss of data or performance.  pSSDs will be designed so that Flash chips that are coming to the end of their useful lifetimes are identified and can simply be removed and replaced with new ones in the same way that light bulbs are removed and replaced when they fail.

  • pSSDs can significantly increase revenues and profits since a higher percentage of manufactured chips can be used in pSSDs than can be used in conventional SSDs because of the increased power of the parallel error-correction system.

  • pSSDs have automatic, built-in backup.

  • pSSDs allow the use of NAND Flash chips that are unusable in conventional SSDs because the pSSD ECC system operates on a two dimensional array of data instead of a one dimensional array as is done in conventional SSDs.

  • pSSDs have features that are highly desirable and commercially valuable but impossible with conventional SSDs.

  • pSSDs have more commercial value than conventional SSDs and therefore they can be priced higher and offer more profit potential than conventional SSDs.

pSSD Pricing Strategy

The price of a pSSD product will be based on its features and those features will be priced on a feature by feature basis which justifies the fact that a pSSD may initially cost more than a conventional HDD of the same capacity.

For example, suppose you went to buy a new PC and were told about two PCs that had exactly the same performance but that one of the PCs took a minute to boot-up and the other one took only a second to boot-up.  What would the "fast boot-up feature" be worth?  Most people would gladly pay $100 to $150 more to get the fast boot-up feature.

The fast boot-up PC will also be noticeably faster at running application programs – especially ones that require large file transfers like transferring pictures or video.  A certain amount of money will be added to a price of a PC if it has a "fast file transfer feature".

Then there is the "automatic, built-in backup feature".  That feature will be priced based upon the amount of backup that is built-in.  For example, a pSSD that allows one Flash chip to fail may add an additional $200 to the price, one that allows two Flash chips to fail might be priced at $300 more and one that tolerates three Flash chip failures might be priced at $400 more.

Each feature will be priced individually.  Pricing each feature individually makes good sense and is reasonable.  That's what is done with automobiles.  When you buy a car, you pay for each accessory or feature individually.  When you buy a PC with a conventional HDD, you do not have the option of adding those features, but when you buy a PC with a pSSD you do.

It would be easy to justify a pSSD price that is substantially higher than an equivalent capacity SSD price.  The extra price is due to the added features.

This is a perfectly reasonable, rational, logical and fair pricing strategy.

Most people are alike, and many will gladly pay a significant premium to get the added features that only a pSSD can provide and a conventional SSD cannot.

Today’s Buyers

Today's buyers are willing to pay whatever it costs to get what they want.

Cell phones.  The biggest market for cell phones is probably teenagers who can't afford them but must have them and find the money to buy them and make high monthly payments to use them.

Coffee.  People regularly pay more for a cup of coffee at coffee shops today than they used to pay for an entire pound of coffee that would probably have made a hundred cups of coffee.

Rather than looking at the price of a pSSD as a negative, it should be looked at as being a positive.  It offers companies the opportunity to price an item higher and make more profit.

If cost was the only factor involved in making buying decisions, there would be no market for Lamborghinis, multi-million dollar houses, leather coats, jewelry, etc.  Many buyers are willing to pay high prices for those items because of the perceived benefits of owning those things.  The same will be true of pSSD products.

The pSSD Downward Cost Spiral

There is a cause and effect cycle as follows:  Once pSSD products start to sell, there will be a large increase in the manufacturing volume of NAND Flash chips, which will cause the costs of Flash chips to go down, which will allow the price of pSSDs to be reduced, which will cause more pSSDs to be sold.

This cycle will repeat with time and can be thought of as a downward spiral. 

As manufacturing volumes of pSSDs increase, costs and prices will continually decrease.

One factor that affects the extent of the cost and price drops is the number of Flash chips that are in a pSSD.  A high number of Flash chips in a pSSD will cause a fast downward cost spiral with a very large cost and price drop.

The most important thing to see is that the early adopters will pay the highest prices for pSSDs, but, once they start to take off in the market place, prices will drop very rapidly and potentially very far.  Nobody knows how far, but it is possible that prices could drop as low as conventional HDD prices – or even lower than conventional HDD prices given enough time and high enough volumes.

It is very important to take the pSSD downward cost spiral into consideration when deciding whether or not to develop a pSSD product.  In other words, NAND Flash chip manufacturers must think about what will happen in the future if large numbers of pSSDs start selling.

Could a pSSD Ever Cost Less Than an HDD?

Yes, it's possible.

Consider a pSSD with many Flash chips as components and a fair amount of failure tolerance.

Flash chips that do not pass the tests for use in conventional SSDs because of too many errors can be used in pSSDs.  Manufacturers of Flash chips could possibly pay a party to take those chips if they currently need to pay a party to dispose of those chips.

Flash chips do not have to be tested before installing them in pSSDs because pSSDs will automatically know which ones are bad and which ones have lots of errors.  The pSSD controller chip can have built-in logic to test untested Flash chips.  The cost of testing Flash chips can be eliminated.

Once pSSDs with a large number of Flash chips start selling in large volumes, Flash chip volumes will be many times pSSD volumes and costs will start to come down very rapidly due to the downward cost spiral.

Because of these factors, it is possible that pSSDs could one day cost less than HDDs.  When and if that happens, HDDs will become obsolete because there would be no valid reason to buy an HDD over a pSSD.

Human Factors

It is important to take into consideration a number of human factors when trying to determine whether or not it makes sense to develop a pSSD product.

When Carl Ledbetter was the CEO of the supercomputer company ETA in St. Paul, MN, he spoke at the University of Minnesota and said he bought a printer for his grandmother, and she was amazed at how fast it could print.  Two weeks later, she was complaining about how slow it was.  That’s the way people are.  There is a never ending desire for more and more speed and higher and higher performance like that provided by pSSD products. 

There was a famous author who lost the entire manuscript of her book because she had it saved on a hard drive and it crashed.  She did not know that data loss was even possible.  Some people have lost entire picture albums because of hard drive failures.  These types of people would greatly benefit from using a pSSD product.

Most normal human beings want automatic, built-in features.  They don’t want to have to spend time and money and effort to get RAID controller boards, extra drives or special software and then have to learn how to use all of them.  Some people who need backups the most would not know how to do those things.  They just want to buy a computer, take it home, plug it in and starting using it without having to worry about losing their data or without having to go do a bunch of other stuff.  There is no doubt that most of them would gladly pay a significant premium to get automatic, built-in backup.

The Value of Data or Content

In most cases, the data or content created by computer users is much more valuable than the computer hardware and software used to create it.  Users may spend hundreds and hundreds of hours to create content and they would be extremely shocked, sad, sorry, unhappy, perplexed, troubled, disappointed, angry, and on and on if they suddenly lose everything because of a drive failure.

Performance Reasons for Developing pSSD Products

Today's hard disk drives are the only components in a modern computer that operate on data one bit at a time!  Think of it!  Processors in modern PCs can operate on 32‑bit or 64‑bit chunks of data at a rate of up to 3 GigaHertz, yet conventional HDDs read and write data one bit at a time!

pSDDs can be designed to allow high I/O data rates to match the data transfer rates of other parallel-transfer components such as microprocessor chips and main memories.

pSSDs can be made failure-tolerant with an arbitrary level of built-in failure-tolerance by using a PRS encoder and decoder.

Failure Tolerance Reasons for Developing pSSD Products

With the use of a PRS encoder and decoder within each pSSD and with R redundant chips in each pSSD, up to R chips can fail with no loss of data or performance.  In addition, the raw error rates of each component Flash chip can be relatively high because the PRS system can correct random errors that the conventional RS Flash decoder does not correct.

In most cases, a pSSD with 1 PRS encoder and decoder will be used with N conventional RS encoders and decoders.  The conventional RS decoders will correct most of the errors due to defects and random errors in each Flash chip.  The PRS decoder will correct errors caused by Flash chip failures.

Reasons for Developing pSSD Products Based on More Effective Use of Manufactured Flash Chips and More Profit Potential

pSSD products could use Flash chips that have been rejected as “unusable” in conventional SSDs because of too many errors and/or defects.  Selling pSSDs which use highly defective Flash chips at normal price levels instead of deeply discounted prices could enable all NAND Flash manufacturing companies to make more effective use of manufactured Flash chips and to realize millions of dollars in revenue that otherwise would not exist.

pSSD products which use NAND Flash chips that are unusable in conventional SSDs will, most likely, be much more reliable than standard SSDs because a “lateral”, “horizontal” or “parallel” ECC coding scheme will be used in combination with the conventional, “longitudinal”, “vertical” or “serial” ECC scheme that is used in conventional SSDs.  The horizontal ECC literally opens up an entirely “new dimension” to the problem of correcting errors because now ECC can be applied to a two‑dimensional array of data items instead of just a one‑dimensional array as is currently being done in conventional SSDs.  No one will be able to legitimately claim that pSSD products which use Flash chips which are unusable in conventional SSDs are in any way inferior to standard SSDs.  In fact, those types of pSSD products will, most likely, be highly superior in performance and reliability to conventional SSDs.

With a number of NAND Flash chips ganged together, the parallel RS decoder and the improved serial RS decoders will have information from multiple, statistically independent sources and the resulting random distribution of errors will be ideally suited for correction using RS codes.

The law of large numbers (from statistics) applies to pSSDs , and the result is that the statistical or probabilistic behavior of the system will closely follow probabilistic models so the behavior of pSSD systems will be very predictable.

Reasons for Developing pSSD Products Related to Users’ Experience

Many users of desktop and laptop computer systems will be willing to pay a premium for a PC or Mac if it has an ultra-fast, failure-tolerant hard drive in it.  If a system already costs over a thousand dollars, many users will be willing to pay an additional premium to get a super-duper, ultra-high-performance, fail-safe hard drive or SSD in the same way that users are willing to pay a premium to get Intel's fastest and most powerful processors.

Once users use a Pentium PC operating at 3 GHz, they will never be willing to go back to a Pentium PC operating at 250 MHz!  There is a market for faster processors because users like them, get used to using them and don't want anything slower once they use them.

The same thing will be true for systems which contain pSSDs in place of conventional HDDs.  Users will buy them because they will only cost a little more than systems that contain conventional HDDs or pHDDs, but they will be much faster, consume much less power and will have automatic, built-in backup.  In a PC, pSSDs will accelerate boot up, accelerate all OS operations and accelerate application programs.  Once users get used to using systems which contain pSSDs, they will never go back to systems that use conventional HDDs or pHDDs.

One major impact to users of PCs which contain a pSSD instead of a conventional HDD would be that, on power up, the operating system would load into memory almost instantaneously – like an "instant on" computer.  Most PC users would love that.

Another impact on computer users would be the increased level of comfort and security a user would feel knowing that, if one or more Flash chip components fail, no data will be lost.  All the user has to do is remove the failing chip and replace it with a new one – just like replacing a light bulb.

Any application programs that do a lot of I/O would also see a significant performance boost – such as programs that download music, movies or pictures.

Legal Issues

ECC Tek did everything within its power to minimize involvement with lawyers.  Getting involved with lawyers and lawsuits is the very last thing ECC Tek wanted.  I have read several books on patents and intellectual property issues, wrote the PRS Patent (except the claims) and wrote and negotiated all of ECC Tek's Agreements with little help from lawyers.  ECC Tek never had any intention of suing any other party and wanted to avoid litigation at all costs because I have seen first hand what extended litigation with an uncertain outcome is like in the case of Rodime’s 7-year litigation with Seagate.  I do not want anything like that and will do everything I can to avoid that type of a situation.

The wisest thing for any NAND Flash chip manufacturing company to do in situations where advanced technology and IP is involved is to immediately acquire any IP that they think they may have an interest in because then they would own the IP and could completely avoid any possible future litigation regarding that IP.  It is the wisest thing to do because the outcome is known.  Nobody can ever know the outcome of litigation and how long the litigation will take in advanced technology cases.  For example, in the case of Rodime, Seagate spent 7 years in litigation and ended up paying a $45 million settlement.  In hindsight, it clearly would have been a much better strategy for Seagate to acquire or license Rodime's patents upfront even if they were overpriced rather than spend 7 years in litigation with an unknown outcome.   Judges and juries cannot understand advanced technology, and they might as well flip a coin to make their decision as listen to arguments.  No judges or juries would understand the PRS technology and patent.

A NAND Flash chip manufacturer could avoid any possible litigation and avoid any possible legal fees regarding the ECC IP I've developed, by offering to acquire it so they own it.

I believe now is the right time for the pSSD technology to get implemented. 

IP Landmines

It is appropriate to use military analogies to get an understanding of certain business situations in highly competitive industries.

If there is a war and the military wants to move into an area that has previously been occupied by the enemy, they must first do their best to detonate or disarm all of the landmines.  It takes time, money, and effort and possibly the loss of equipment and lives to do it, but there is no other choice.  If they don't do it, they risk a much larger loss of time, money, equipment and life later on.

The landmine analogy applies to today’s high tech businesses.  IP owned by competitors are the landmines that can potentially result in expensive and extended IP litigation with uncertain outcomes.  If potential competitors have been in a technology area before you decide to go into that area, you may come across some IP landmines that lead to lawsuits.  The only reasonable thing to do in that situation is to sweep the area of IP landmines before you enter that area.  IP landmines are detonated or disarmed by acquiring the IP so you own it.  If you own it, it can't hurt you later on.  You might suffer some small losses in the process, but it is much better than risking much larger losses later on.

 ECC Tek's Failure-Tolerant Designs Have Become the Standard in Space

ECC Tek's parallelized and pipelined RS designs have become the de facto standard for developing failure-tolerant storage systems for spacecraft.