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Flash chips with 300,000 write cycles are common, and currently the best flash chips are rated at 1,000,000 write cycles per block (with 8,000 blocks per chip). Now, just because a flash chip has a given write cycle rating, it doesn't mean that the chip will self-destruct as soon as that threshold is reached. It means that a flash chip with a 1 million Erase/Write endurance threshold limit will have only 0.02 percent of the sample population turn into a bad block when the write threshold is reached for that block.

The better flash solid state flash drive manufacturers have two ways to increase the longevity of the drives: First, a "balancing" algorithm is used. This monitors how many times each disk block has been written. This will greatly extend the life of the drive. The better manufacturers have "wear-leveling" algorithms that balance the data intelligently, avoiding both exacerbating the wearing of the blocks and "thrashing" of the disk: When a given block has been written above a certain percentage threshold, the solid state flash drive will (in the background, avoiding performance decreases) swap the data in that block with the data in a block that has exhibited a "read-only-like" characteristic.

Second, should bad blocks occur, they are mapped out as they would be on a rotating disk. With usage patterns of writing gigabytes per day, each flash-based solid state flash drive should last hundreds of years, depending on capacity.

If it has a DRAM cache, it'll last even longer.

1997 called, it wants its caveat back.
http://www.storagesearch.com/ssdmyths-endurance.html http://www.bitmicro.com/press_resources_debunking.php

832GB 2.5-inch SSD
1.6TB 3.5-inch SSD

source - ofpblog

832GB 2.5-inch SSD
1.6TB 3.5-inch SSD

source - ofpblog

They simply raided two of their 416GB drives :)

Which was their previous high late last year.

http://www.bitmicro.com/press_news_releases_20070911.php

The bit I'm slightly skeptical on is the environmental specs. While -40C and +85C are becoming a more common standard, not many SSD manufacturers can reliably hit past -25C and +75C. This may not seem that big of a deal, but in some industries - which would currently be the only ones spending Close to the $10k (judging by current pricing for extended/extreme versions of these drives) for them initially - this is huge if true.

They've already announced a 1.6TB flash drive for launch around mid-2008.

There is. I got to play with some kit at OOW last week. Bitmicro had a booth with all sorts of HDD's in server form factors and interfaces (SCSI, Fibre Channel, Sata, Pata). While it is not cheap - $20USD/gig? - it is getting better with each price drop. The drives were cool compared to my old fashion disks, so it might already be at the break even point for people who count air conditioning into the cost. I'd love to replace my raptors with a fast, quite, cool, flash based device - just waiting on the cheap....

Wish there was a DDR2 version of the iRAM out there (for not stupid money) that could do better than 4x1G. Starting to see 2G sticks going for peanuts these days.

In a recent article on write endurance published in STORAGEsearch.com, editor Zsolt Kerekes provided theoretical computations on the longevity of solid state flash drives deployed in enterprise server applications. His test solid state drive had the following specifications: total capacity of 64GB, sustained write speed of 80MBps and a write endurance rating of 2 million cycles. By assuming that data is written in big blocks and there is perfect implementation of wear leveling techniques, Kerekes estimates disk endurance at 1.6 billion seconds, which translates to 50.74 years.

Debunking Misconceptions in SSD Longevity

They already use http://www.bitmicro.com/

So Sandisk gets press for doing this. Memtech and Bitmicro have had solid state flash drives for well over a year, with SCSI, SATA and PATA interfaces as well. And they range up to 64Gb.

Bitmicro

Memtech

And there are most likely even more out there. These are just the ones I know of.

Well, they say that they are.

http://www.bitmicro.com/products_edisk_35_ide.php

http://www.bitmicro.com/

If you have a look there you will find some pretty decent spec solid state drives that are US DoD certified. With their secureErase system, they claim to be able to safely and securely erase data in a fraction of the time it takes with other flash based systems. They can also be setup to erase the data if power is lost for any reason (eg. being shot down). There are huge advantages for solid state storage over traditional HDs in the military. Who cares if it costs hundreds or thousands of dollars more, they are the military.

If you want a Flash drive..... buy one ;-)

http://www.bitmicro.com/products_edisk_25_ide.php

I'm not 100% certain where you can purchase them, but when I looked into it ~6 months ago I did find some avaliable for online ordering.

With usage patterns of writing gigabytes per day, each flash-based SSD should last hundreds of years, depending on capacity. If it has a DRAM cache, it'll last even longer.

http://www.bitmicro.com/ have 2.5-inch with sizes of 512 MB to 73.7 GB , but I read that samsung will be the first for the mass market. These solid state storage devices, with there faster access times,can be great for improving mail and database performace without out having to do any upgrades.

As I see it, the force of this disk, is the really short time to sync. Running Oracle redo-log on sonething like this would be nice. Or the entire database if it fits.

But if I had the money, I would rather put it here http://bitmicro.com/products_storage_devices.php

In saying that, there are companies that do make Flash based solid state disks that solve most of these problems. I'd say that even the finite write/erase life is made less of an issue by large ammounts of caching and something akin to RAID 6. Since those manufacturers supply for military applications, be prepared to pay massive ammounts for it.

I can't see the cost of producing NAND Flash chips (even at 16Gb) in high enough quantities to equal the cost per GB of HDs. Once the cost drops further, packaging enough of them for redundancy into a 2.5" form factor with all the caching other circuitry (most likely some kind of hardware RAID 5 or 6 controller) will start to make economic sense. Until then I think we are stuck writing magnetic bits onto spinning chunks of metal. ;)

I have a slight problem with this in general and with your scenario specifically.

Many small systems that I have setup boot from flash card, run in RAM and only write to the flash card when the configuration changes. Logging was forced to ram disk or disabled completely. This was done deliberately to avoid some of the problems with write endurance. I have had small Linux routers/firewalls running like this for 2-3 years now, so it must work. Distributing the wear across the entire flash card in this scenario might work quite well to extend the life since most of the disk is read mostly with only small, infrequent writes. I must assume, however, that there is still a finite life and that the system is doomed to fail at some point. Whether this is measured in 10's of years or 100's of years, I don't know and would have to do some lengthy profiling of the software and calculations to estimate.

In your scenario (i.e. running flash as a swap device) the flash memory is written much more often. In addition, I must assume that most of the flash is being written to almost continuously. After all, since memory limitation is what you're trying to overcome, I must assume that a large part of the 128M swap is being used most of the time. In this case, distributing wear across the whole flash is unlikely to do any good.

This site has calcs for predicting wear-out on flash-based disks:
http://www.bitmicro.com/press_resources_flash_ssd_ db2.php

The results range from almost useless (1.71 years) to who cares (130 years - I'll be dead by then) for 512 byte sectors on a flash disk device.

I design microcontroller hardware for a living and have had to deal with write endurance on EEprom (the technology flash is based on) for many years now. Although write endurance has been going up (it used to be several 1000, now it ranges to 10^5 to 10^6) it is still a concern in many of my designs. For instance, on a data logger I worked on recently, I went to a battery-backed RAM design rather than flash based. The battery-backed RAM design was good for about 10 years (limited by battery shelf-life) and the flash-based design would theoretically have worn out after only 6 months.

Replacing disk with flash RAM is not feasible: flash isn't fast enough, and doesn't survive enough re-writes to the same blocks.

It's not only feasible, it's been done. It's horrifically expensive, but it works. A "wear leveling" algorithm is used to ensure the same flash cells aren't erased and re-written continuously. Heck, even the flash keychain drives and digital camera cards do that. No, it probably won't hold up to as many write cycles as a magnetic disk will, but writes are much less common than reads, especially in some database and web applications. The drive doesn't need to last forever anyway, since the computer it's part of won't either. I've heard that these guys have had one of their flash drives on a continuous rewrite cycle for a few years now - no errors yet.

Where do you get the notion that flash is slow? It's slow compared to RAM, but it's way faster than a hard disk. That's one of the selling points of these things.

Don't worry! Solid state hard drives appeared already. Now it's just matter of the price dropping. I give it 5 years.

MTBF specs vary based on the manufacturer and the calculation used; the following are some sample specs I have found:

Pretec --> MTBF 500,000 hours (powered on)
Simpletech --> MTBF 1M+ hours
SanDisk --> MTBF 3M+ hours
BitMicro --> MTBF 2M+ hours


But the most reliable and experienced guys around are BitMicro, and this is what they pubish for one of their flash drives:

http://www.bitmicro.com/...urces_flash_ssd_db2.php

Example #2: Write Frequency in MB/sec

E-Disk® PB Size = 16 KB

I/O Block Size = 64 KB

Write Frequency = 6,016,204,800 KB per day (68 MB/sec)

E-Disk® capacity = 155,648 MB
Number of Flash chips = 608
Size of Flash chips = 2048 Mbit or 256 MB or 262,144 KB


Number of writes to Flash chip = 64 KB / 16 KB = 4
Total E-Disk® physical blocks = (262,114 / 16) x 608 = 9,961,472
Total max writes to E-Disk® drive = 9,961,472 x 1,000,000 = 9,961,472,000,000

Endurance (in days) = 9,961,472,000,000 / (4 X (6,016,204,800/64)) = 26,492 days
Endurance (in years) = 199,229 days / 365 = 72.59 years

Again, please refer to this paper about flash technology in HDD applications. The document is a bit lengthy, but the conclusion is that today's flash technology allows for enough erase/write cycles to make them more than viable for HDD use.

Here's a great paper about flash technology in HDD applications. The document is a bit lengthy, but the conclusion is that today's flash technology allows for enough erase/write cycles to make them more than viable for HDD use.

There have been several vendors of Flash Based hard disks for a while. This is the first hybrid flash+magnetic drive -- and even this isn't all that different of an idea than say a Compaq smart array controller with battery backed write cache which used NVRAM to store data. It's innovative and i'd definitely buy a laptop that had it.

I think many slashdotters will miss the big picture. This is mostly a power saving utility -- and it could offer performance gains assuming the files you use are available on the flash and the drive doesn't need to be spun up. (Of course when the drive DOES need to get spun up, plan on having a *really* long access time so I think this will be negligble). Buy basically it means you can leave auto-save on Microsoft Word enabled and not drain your battery.

BUT since we're on the subject i'm a huge fan of flash only drives, they have several special applications because of their access times (in nanoseconds instead of milliseconds), extremely reliable (no moving parts, read/write cycles in the billions + ECC checking) and high bandwith they are NOT ideal for situations such as swap (JUST BUY MORE RAM IT'S CHEAPER AND FASTER!!) but instead they are perfect for situations were you need persistent storage of highly accessible files e.g. binlogs on a database.

You can easily bump up the performance of MySQL or Oracle using one of these drives for A LOT less

There is a company called BitMicro http://www.bitmicro.com/ which produces ATA and SCSI, and Fibre Channel flash only hard disks.
Using a flash only drive you will get a dramatic performance bump in any transaction database by storing the transaction files on the database.

I did a quite Google of the term and got http://www.bitmicro.com/products_edisk_35_ide.php.

I also found a dicussion on Sharky's forums from back in 2001 about this very issue. I doubt we'll ever see one, but you never know what those crazy people in Hong Kong will hack out next.

I tried this a number of years ago. In fact, there's an CF->IDE interface board that is very inexpensive that I purchased. Turned out that CF was much slower than my hard drive.

Might be interesting to try it again with today's professional flash memory, but with readily available CF memory from about 3 years ago, I was able to install a Windows OS on it but it was slower than my hard drive.

If you really want something like this, there are memory drives that use actual battery-backed up RAM (take your pick of varities) that are as you would expect lightning quick. Last I checked though Bitmicro's Site, they were very expensive.

Cenatek pci ram disks

BitMicro

M-Systems

You could probably find one for normal sdram, but to find a device that goes from 40/80pin ide to laptop SO-DIMMS is going to be a challenge.

Check out these solid state HD's.

I'm sure there'll come the time when spinning disks (either floppy or HD) will come to an end and become just pieces of junk in a museum - like vacuum tubes in electronics.

How about, from their website, for an "Enterprise" FC 3.5" disk:

MTBF - 2 Million Hours

http://www.bitmicro.com/products_edisk_35_fc.php

That works for me as far as durability goes. /fain

From the site, the specs on this device state MTBF 2,000,000 hours. I'm more interested in how they came up with that number.

Sounds really cool, I would love to keep the OS and swap on one of these and use an SATA or IDE drive for storage. Little nervous about using what sounds like a "1.0" release.

I predict MRAM will be the near replacement. It leverages all that we've learned in chipmaking, and hard drives(1). Think of hard drives as a simplified mram (or core memory for you old school guys).It will be easier to do something like this because of the lower power consumption, and hence heat. The main issue is economic, and time will take care of that.

(1) What we've learned from flat-screen technology will help as well.

http://www.bitmicro.com/products_edisk_25_ide.php [bitmicro.com]
E-Disk® 2A66(2), 17408MB, Commercial Temp, No PowerGuard, NAND
E-Disk® Part Number: D2A066B 017408 CNN
Discounted Unit Price: $18,857

-- -- -- --

http://www.bitmicro.com/products_acedisk_25_IDE.ph p [bitmicro.com]
Ace-Disk 2A16, 2048MB, Commercial Temp, No PowerGuard, AND
Ace-Disk Part Number: A2A016B 002048 CNA
Discounted Unit Price: $1,356

-- -- -- --
SSD
pricing has been coming down over the last few years as the performance
continually improves. We expect the pricing to reach the consumer
level in the next 3-5 years. Two years ago we were roughly $15/MB, last
year $5-8/MB, and this year we are ranging from $1-4/MB depending on
interface/model and capacity.

http://www.bitmicro.com/products_edisk_25_ide.php [bitmicro.com]
E-Disk® 2A66(2), 17408MB, Commercial Temp, No PowerGuard, NAND
E-Disk® Part Number: D2A066B 017408 CNN
Discounted Unit Price: $18,857

-- -- -- --

http://www.bitmicro.com/products_acedisk_25_IDE.ph p [bitmicro.com]
Ace-Disk 2A16, 2048MB, Commercial Temp, No PowerGuard, AND
Ace-Disk Part Number: A2A016B 002048 CNA
Discounted Unit Price: $1,356

-- -- -- --
SSD
pricing has been coming down over the last few years as the performance
continually improves. We expect the pricing to reach the consumer
level in the next 3-5 years. Two years ago we were roughly $15/MB, last
year $5-8/MB, and this year we are ranging from $1-4/MB depending on
interface/model and capacity.

http://www.bitmicro.com/products_edisk_25_ide.php [bitmicro.com]
E-Disk® 2A66(2), 17408MB, Commercial Temp, No PowerGuard, NAND
E-Disk® Part Number: D2A066B 017408 CNN
Discounted Unit Price: $18,857

-- -- -- --

http://www.bitmicro.com/products_acedisk_25_IDE.ph p [bitmicro.com]
Ace-Disk 2A16, 2048MB, Commercial Temp, No PowerGuard, AND
Ace-Disk Part Number: A2A016B 002048 CNA
Discounted Unit Price: $1,356

-- -- -- --
SSD
pricing has been coming down over the last few years as the performance
continually improves. We expect the pricing to reach the consumer
level in the next 3-5 years. Two years ago we were roughly $15/MB, last
year $5-8/MB, and this year we are ranging from $1-4/MB depending on
interface/model and capacity.

http://www.bitmicro.com/products_edisk_25_ide.php
E-Disk® 2A66(2), 17408MB, Commercial Temp, No PowerGuard, NAND
E-Disk® Part Number: D2A066B 017408 CNN
Discounted Unit Price: $18,857

-- -- -- --

http://www.bitmicro.com/products_acedisk_25_IDE.ph p
Ace-Disk 2A16, 2048MB, Commercial Temp, No PowerGuard, AND
Ace-Disk Part Number: A2A016B 002048 CNA
Discounted Unit Price: $1,356

-- -- -- --
SSD pricing has been coming down over the last few years as the performance continually improves. We expect the pricing to reach the consumer level in the next 3-5 years. Two years ago we were roughly $15/MB, last year $5-8/MB, and this year we are ranging from $1-4/MB depending on interface/model and capacity.

http://www.bitmicro.com/products_edisk_25_ide.php
E-Disk® 2A66(2), 17408MB, Commercial Temp, No PowerGuard, NAND
E-Disk® Part Number: D2A066B 017408 CNN
Discounted Unit Price: $18,857

-- -- -- --

http://www.bitmicro.com/products_acedisk_25_IDE.ph p
Ace-Disk 2A16, 2048MB, Commercial Temp, No PowerGuard, AND
Ace-Disk Part Number: A2A016B 002048 CNA
Discounted Unit Price: $1,356

-- -- -- --
SSD pricing has been coming down over the last few years as the performance continually improves. We expect the pricing to reach the consumer level in the next 3-5 years. Two years ago we were roughly $15/MB, last year $5-8/MB, and this year we are ranging from $1-4/MB depending on interface/model and capacity.

"It seems like the most problematic part of any notebook is the speed of the hard drive (and they also get noisy). I noticed http://www.bitmicro.com/products_edide.html selling 2.5" solid state disks SSD. Anybody currently using one of these in a notebook? I can't find pricing anywhere, but they've gotta cost a fortune." How long do you think it will be before the major laptop manufacturers start adopting this technology?

Actually, they say that typical endurance is 27 years for a drive that gets written 100GB a day and 28000 years if the drive gets written only 100MB a day. And those are just for 1GB model. 4.6GB model can take 100GB a day and still survice 123 years. I'd call that damn reliable. No details how they do that but I guess there's some hardware layer that remaps new data to least used areas.

The only thing I don't like is the read and write speeds. And the price, probably.

From their own Applications page you can see that their not even looking for the laptop market:

Portable Computer Applications

Notebook and laptop computers will use Solid State Disks as the main external memory storage because of their low power consumption and resilience to mechanical stress. There is no need for the external memory storage to withstand environmental conditions that are better than those required by the LCD screens. LCD environmental requirements are generally more restrictive than those for mechanical disk drives.

The majority of portable computers will continue to be equipped with magnetic and optical mechanical drives. The competition in this market will be challenging because the customers in this market will be price sensitive. We still believe that some customers who need the higher performance and reliability of our E-Disks® will be willing to pay more.

Not that it isn't a good idea, but they are just not going to price them to compete with the standard Magnetic disks. But looking at the performace these would kick butt in any server application!

From their own Applications page you can see that their not even looking for the laptop market:

Portable Computer Applications

Notebook and laptop computers will use Solid State Disks as the main external memory storage because of their low power consumption and resilience to mechanical stress. There is no need for the external memory storage to withstand environmental conditions that are better than those required by the LCD screens. LCD environmental requirements are generally more restrictive than those for mechanical disk drives.

The majority of portable computers will continue to be equipped with magnetic and optical mechanical drives. The competition in this market will be challenging because the customers in this market will be price sensitive. We still believe that some customers who need the higher performance and reliability of our E-Disks® will be willing to pay more.

Not that it isn't a good idea, but they are just not going to price them to compete with the standard Magnetic disks. But looking at the performace these would kick butt in any server application!

They do exist, but are fairly expensive. I've never seen one but everything I've read says they go like shit off a shovel, not sure how good they are for long term storage though.

But....

They're expensive.

Keep in mind that the answer to the question "why don't they" is almost always to be found in the finances of the question at issue.

With that in mind, go visit here for exactly what you've all been looking for.

Btw/ if anyone wants to donate me a few (say 136) of the beasties and an controller to go with them, I'd be most appreciative...

...I've been running Linux on SS disks for some time now. I use the BiTmicro E-Disk line.

...I've been running Linux on SS disks for some time now. I use the BiTmicro E-Disk line.

When a competing technology starts selling competitive devices (capacity, size, speed, reliability, etc.) at reasonable costs then I'll pay more attention.

On a side note, a little company called BiT Micro manufacturers high performance solid state storage devices in hard drive form factors, though at considerably higher cost.