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Ultra Fast Disk Drives With No Moving Parts
saccade.com writes "Let's face it, the slowest part
of PC's today is the disk drive. Bit
Micro has come up with a nifty solution - flash memory based
disk drives available in typical
disk
form-factors. These e-disks are electrically compatible
with ATA, SCSI, etc. but run orders of magnitude faster - access
times down to 40 usec and transfer rates over 100 MB/sec. What's
the catch? Cost. Currently going for just under $1K/G, a 30G model
I recently held in my hand was worth much more than my car. However,
as flash memory prices drop, so do the price of these drives.
Within the decade the spinning hard disk may go the way
of the floppy and CRT."
This isn't exactly new. They've come down substantially in price and gone up in volume, but these have been around for years. It is my understanding that the most significant use was (is?) laptop drives for extremely rugged, shock-resistant portables.
That what was all this school was for... to teach us how to solve our own problems. -- janeowit
Within the decade the spinning hard disk may go the way of the floppy and CRT
As an aside, my CRT is still firmly wedded to my desktop, and won't budge until flat screen technology has caught up. It's come a long way, and may be good enough for less demanding applications, but it's got a way to go before I have a flat screen on my desk...
"The invisible and the non-existent look very much alike." -- Delos B. McKown
This Canadian retailer: http://www.go-l.com has Windows XP pre-installed on an in-house flash drive. From what I gather, it boots VERY quickly. AND Yes, the LCD panel on the case is quite sexy. Aye.
Flash devices only have a read/write cycle of a few hundred thousand. Sounds like a lot, until you realize that the file table gets written to at least that much within a year of use. I'd go for a battery-backed SDRAM array, say PC-133-ECC. Pricewatch has 1GB sticks for $160. That's 10GB of ultra-high speed storage for $1600. Add a couple hundred for a memory and SCSI controller, a few batteries, and you're golden.
My Other Computer Is A Data General Nova III.
Pu RAM And sorry, they're a California-based company, not Canadian. Drat.
1) By the time storage size is adequate to hold today's OS's, the OS's will have grown because magnetic disks offer so much more space. In other words, you can take a 512MB flash drive and boot up an older OS (like Win9x).
2) Flash has a limited amount of Read/Write cycles per cell. Don't put a database on that drive! I know there are algorithms that can minimize this, but the limitation is still there.
Remember, You are unique...just like everyone else.
First of all, the technology used in a product like this is not radically different from existing flash solutions. The big problems are cost and limited use -- flash memory (transistors with high voltage-forced states) can only be toggled a limited number of times. So there is a limited number of write cycles for the faster types of non-volatile solid state memories.
That problem can be reduced by padding devices with large amounts of RAM (write caching). But the breakthrough is coming soon, with new flash technologies that are better designed for continual writes (without compromising speed). From what I've read in IEEE Spectrum, the better technologies suited for mass storage are in research labs right now, meaning maybe 5 or 10 years til market.
I dug a bit and found this in the manufacturer's FAQs:
QUESTION: What is the lifespan of the E-Disk® flash drive if wear-leveling algorithm is not utilized? How much improvement will BiTMICRO's wear-leveling algorithms make to this number?
ANSWER:
The wear-out life of an E-Disk® flash drive is directly proportional to the number of flash memory physical blocks in the device. The greater the number of flash memory blocks in the flash drive (and therefore total capacity), the longer the wear-out life of the device. As an example, arithmetic computation will show that a 34GB E-Disk flash drive fitted with flash chips rated at an endurance limit of 1 million erase/write cycles will have an endurance life of 1,024,000,000 seconds (or 32.47 years) when written continuously at 34MB/sec (or 2,937.6GB Erase/Write per day). This is the worst possible scenario where all I/O is 100% write and caching is disabled. E-Disk erase/write endurance can be more than 15 times the computed value if the multiplier effects of full associative caching and the results of BiTMICRO's accelerated erase/write endurance verification and testing are included.
in the Edisk FC datasheet they state that:
Write endurance (Typical): 27 years@100GB/day erase/write cycles
That was for the 1G Edisk. Now assuming that this is sequential access, it would imply 100 passes/day * 365 * 27 years = 985500 erase/write cycles.
Because the controllers do just that, they control the command order and optimize sequences based on the order they are received.
We could get rid of SCSI or ATA but there will still be a controller for the media unless its integrated into the drive.
Are you intolerant of intolerant people?
According to their web site, their "Patented Wear Leveling" algorithms attempt to spread write operations over the disk. My guess if you have a frequently written file/record/whatever is that it doesn't write it to the same place each time. It also looks like they have a "Flash Wear-Out Monitor" to warn you when the device has exceeded 95% of it's MTBF rating, though they say that the device may last beyond the rating. Also, looks like their "Automatic Bad Block Remapping" moves data to spare blocks if a block fails. So, yeah, like you said, they work around the dead bits remapping them to a new area, as well as constantly spreading write cycles across the device. Looks like they've really thought this through. Of course, so long as the price exceeds that of spinning platters, it'll be a niche product.
As far as "Within the decade the spinning hard disk may go the way of the floppy and CRT" goes, I guess that means that there will be other/better/different choices than spinning platters, but they'll still be more expensive and spinning platters will still be the norm. Looking forward to the status quo, I guess!
Flash uses a so-called "floating gate" to hold charge. The floating gate sits between the control gate and the source/drain/body of the transistor. When electrons are stored on the floating gate, the transistor is prevented from turning on, producing a zero. When there's no charge, the transistor turns on normally, producing a one.
Visit the
I think this link can be usefull if you're interessed in this technologies:
l
http://www.storagesearch.com/ssd-buyers-guide.htm
"Use cases are fairy tales..." I. S. 2005
"Single-level cell" flash memories can manage over 100,000 writes per sector. "Multi-level cell" flash memories, which slightly lead single-level on the density/time curve, can manage only roughly 10,000 writes per sector. Learn more about the difference between single- and multi-level cell flash memory.
With this thing rated at up to 25,000 IOPS, is would seem that they might not last all that long (4 seconds?).
Yeah, with tens of thousands of writes to the same sector. CF flash memories already perform some sort of wear leveling to spread repeated writes over multiple sectors. Yeah, it's more difficult for swap files, but I expect that rather than use a swap file on flash memory, PCs with solid-state storage will use more volatile memory.
Probably, a better HD-replacement solution would be based on MRAM, which is being steadily developed and is going to become available quite soon (the article linked mentions late 2004).
Computers make very fast, very accurate mistakes
1. Typical industrial flash will do 300k/cycles, higher end stuff is in the million+ range.
2. Just because its rated at lets say 1000000 cycles, doesn't mean at 1000001 cycles its going to die. It means that a certain percentage (i've seen it quoted as 0.02%) will fail at roughly that many cycles.
3. The manufactures aren't dumb. The better ones use several methods to distribute the load evenly as to get the most life out of the write/erase cycles. They distribute the load, they balance the number of write cycles, and many use some RAM to handle 'thrashing' situations where a single block gets continuously rewritten.
With current tech. (barring unusual circumstances) you can expect these drives to last decades if not longer.
As for the BitMicro:
27 years at 100GB/day for the 1GB model
123 years at 100GB/day for the 4.6GB model
Way more information can be found at
http://www.storagesearch.com/ssdarticles.html
Try using the OO pre-loader, it will give you a better comparison.
MSOffice preloads at start. It would be fair to preload OO too. Anyway, it is probably slower. OO is a very bloated program, but it might get leaner with time.
Compact Flash is already IDE. It's just that the pinouts are different. You can buy an adapter for ~ $20. The previous poster was correct about the maximum number of writes though. I have a system that I use compact flash to boot off of in RO mode. My system boots fast and I don't write to the disk.
Encryption: I may not agree with what you say, but I will defend your right to encrypt it...
I don't know much about flash memory technology or the reliability associated with it. I don't give a hoot how fast it is. If it's solid state (no moving parts) and can guarantee me it won't one day decide to utterly destroy itself, I'm sold.
Total self-destruction of whole chip at once probably isn't very likely, but it WILL wear out with time.
A block of flash can only take so many write-cycles before it's done with. It might last for a long time if you'll use it in WORM fashion, but if you're planning on replacing typical desktop hard drive with flash, it'll probably be dead long before the HD would be.
I can't think of the last time I heard someone call tapes "cheap". Several thousands of dollars for a single drive is not what I'd call cheap... Especially since the tapes themselves are about as expensive as IDE drives per GB (which don't require buying a several-thousand dollar part before you can use them).
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