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Solid State Memory on the Rise
skaet writes "CNet is reporting that manufacturers of NAND flash memory are expanding the market for their chips - over the next few years - to eventually replace current methods of storage in media capture devices, mobile phones and even some notebooks as well as car navigation systems and large data storage at corporations and government agencies. From the article: 'The average notebook has 30GB (of hard drive storage). How long is it before the notebook has solid state memory? Five or six years,' according to Steve Appleton, CEO of Micron Technology, one of the world's largest memory makers. 'I'm not saying drives will go away. There will always be a need for storage, but when was the last time you tapped out a drive?'"
Gigabyte has something out they call i-RAM. It's a PCI add-in card that allows you to plug regular ram sticks into and then access them as a piece of solid storage space. They say its good for "multimedia applications" and I'm sure it is...if not a little overkill.
Here's a link to a review from Anandtech http://anandtech.com/storage/showdoc.aspx?i=2480
Most solid-state memory is pretty darn slow...
I was once asked to demo a solid-state HD...built with nothing but DRAM. This was a decade ago, and it was only proof-of-concept. It was only 2gb, but it would format instantly. Don't confuse SD and CF cards with DRAM. Micron makes DRAM.
What is the expected lifespan (in cycles) for flash memory? I thought it was only good for a few thousand writes.
Has it improved recently?
This topic arose when people started using flash memory as a hard drive in old Powerbook 1400s. While they're a nice very expandable old powerbook, they have a RAM ceiling of 64MB. a G3/400 CPU expansion in them is one thing, but being limited to 64MB is a pain in the butt.
So popping a flash ram card in and using it as the virtual memory drive let PB1400 owners use 128, 256MB of virtual memory, running off the flash ram which was far quicker than the internal HD for swapping. Many people have also used these cards as the main boot drive so the whole OS boots from RAM, swaps to that same RAM, and gives mostly silent operation and saves on battery life. Critics of doing this noted the drives would last a month or two until suffering write death.
Systems running these cards have been seen working just fine for 3-4 years now. Write limits in the range of tens to low hundreds of thousands may not seem much, but in reality it's working quite well. Apparently part of this is that most newer flash ram drives are set up to attempt evenly distributed writes over cells, and not concentrate hundreds of writes one after another on the same cell
I remember reading that flash memory can only be rewritten only about 10K-1M times. It works Ok for USB memory sticks, but having a page file on a solid state disk would destroy it in no time.
SD cards are slow. Flash memory is not.
The whole point of using memory instead of a hdd is because of speed; the long time for your mp3 player to fill is due to the transfer rate of whatever you're hooking it up to (ie usb).
That's not entirely correct.
While if you hook up a flash memory to the USB 1 spec, it will be painfully slow, even with a connection to a high-speed USB 2.0 hub, you'll still run into slowdowns. Why? Because most flash (which is most, if not all non-disk related MP3 players) write speeds are averaging around 5-10MB/sec. And even then, that's being generous.
So, for 10MB/sec, that would be at least 1 minute to fill up a 512MB mp3 player. Of course, real world is never the same as rated specs, so I'd be happy with 2 minutes, to be honest....
Another neat trick to try with Flash drives is to fill them with a bunch of itty bitty files - it literally takes forever to do so! Maybe someone more insightful than I can enlighten me as to why that is....
Karnal
Search for "ramsan" :
The RamSan-400 hooks up via a 4GB Fibre Channel interface and has 3000 MB/s random sustained external throughput. That's three gigabytes per second. Sustained. Importantly, it can also handle 400,000 I/Os per second, with a latency of less than 15s.
Nope, you're thinking of non-volatile RAM. This is nothing more revolutionary than a huge pile of flash keychains -- and about as fast to use. So yes, laptops with this will still need RAM.
But yes, IF we do eventually get non-volatile RAM that's as fast as volatile RAM and cheap enough to replace hard drives, we will have to do some rethinking of OS and software design.
Well, true, we won't HAVE to -- stuff does work off ramdisks and tmpfs, but those are still designed to go away when the computer shuts off. The programs which were smart enough to mmap everything and let the OS manage the caching will be the fastest for a long time. And we'll have to decide how to represent the new memory. It seems to me you'd have to call it RAM and come up with a way for the ramfs to persist, while still allowing "reboots", because the alternative is calling it a "disk" (setting aside some space for "RAM") -- yes, you could create huge swap spaces, but swapping to RAM is still slower than just using the whole space as RAM.
Unfortunately, I'm guessing that by the time everyone stops hopping up and down about how exciting the new tech is, we'll have it running unmodified Windows with so many hardware kludges to make it work that the system is slower and stupider for everybody else, too.
Don't thank God, thank a doctor!
The slowdown is due to the file system: FAT. Everytime a (small) file is written, the File Allocation Table needs to be be (re)written too.
It's just one of those great things MS has given us.
I'm not sure what you're claiming. Both of those pages list the hard drive capacities for base configurations, not the "up to" capacities. I know as a fact that the current generation iBook G4s start off at 40GB.
THE NERD IS THE COMPUTER.
I'd really like to have a laptop with a few GB of flash memory that acts as a read and write cache for the hard drive. With a good caching algorithm, it should be possible to keep the hard drive spun down most of the time and save a ton of energy
You are not the only one thinking of that.
"Another neat trick to try with Flash drives is to fill them with a bunch of itty bitty files - it literally takes forever to do so! Maybe someone more insightful than I can enlighten me as to why that is...."
The NAND memory used in flash drives are optimal for sequential writes due to the large erase blocks which can reach a couple hundres kilobytes. When you write small files, it has to copy everything in that erase block to a new location except the small portion it changed. This results in significant overhead. Reads don't have that issue since no modifications are done.