Japanese Scientists Develop Long-Life Flash Memory

schliz writes "Flash memory chips with a potential lifetime of hundreds of years have been developed by Japanese scientists. The new chips also work at lower voltages than conventional chips, according to the scientists from the University of Tokyo. They are said to be scaleable down to at least 10 nm; current Flash chips wouldn't be usable below 20 nm."

Comments

What is the point?

[damburger]

Given that we tend to dump flash memory whenever a larger and more compact one comes along, and transfer our data, what use is there for a flash chip that will keep data for 100 years but be obsolete in 2?

Re:What is the point?

[jacquesm]

it's to facilitate the new profession of 'data archaeologist'. People that will be sifting through the digital detritus of the pre-AI era two hundred years from now.

Looking for the rosetta's stone that will enable them to translate 'flash' into 'realmedia' ;)

Re:What is the point?

[MyLongNickName]

I would hardly call 100 years archival. In some exceptional cases its within the memory span of a single human individual.

Ummmm. Yea. I am going to have granny memorize my last ten years of photos, movies and financial records.

Fact is, I have struggled with a good method for backing up all of this. I've basically settled on mirroring with a remote FTP site. It works, but with my horrible upload speed, initial synchronization took 48 hours plus. Quarterly updates take a couple hours. And the other pain in the butt is I have to encrypt my financial info as I don't trust it being in the hands of a third party.

Now if I had a medium that were 99% successful at retaining info for 20 years, I would backup to two manufacturer's media, and stick it in my safety deposit box.

I don't have that degree of confidence in any low cost storage media yet.

So for archival, yes, this is a wonderful advance.

Re:What is the point?

[jimicus]

Archival. Once it's archived you can forget about it. For example, your local library doesn't convert all that old microfilm just because it can. It would only do it to put it onto a more stable storage medium.

At least until the technology changes so much that you can no longer buy anything that will read it, cf. the BBC's Doomsday project:

http://www.iconbar.com/forums/viewthread.php?newsid=937

Re:What is the point?

[MyLongNickName]

I'm assuming you are under 30 and haven't lost a grandparent. Now that I have lost a few family members, I wish I had more photos, more memories to look through. Perhaps it is a case of you don't miss something till it is gone.

I will pull up the digital photo album of old vacations, and my kids love to remember what we did. At some point, my kids will become uninterested as I did when I was younger. But as some point, I know they will enjoy revisiting them.

I sure as hell don't want that to not be possible because my hard drive crashed.

Re:What is the point?

[jim.hansson]

i have heard stories from universities that they sometimes get help requests from people that have data stored on mediastypes that nobody has readers for anymore, and after a little hunt in basements and other places they find the hardware, then there is the problem of software. There is already companies specializing in this sort of things

Re:What is the point?

[Free the Cowards]

It doesn't matter what you write, because the logical sectors are not linked to the physical sectors on any reasonable flash drive. The controller circuitry holds a mapping which it adjusts as time goes by to evenly use the entire device no matter what your write patterns are.

As for "not much cheaper", this must be a new meaning of "not much" that I was previously unaware of. Taking a quick sample on newegg.com, I find an 8GB flash drive for $32, and 8GB of RAM going for around five to six times that. The flash drive, in addition to being vastly cheaper, is also much smaller and consumes much less power.

Re:What is the point?

[Anonymous Coward]

I guarantee you that the $32 8GB flash drive is not what you call 'reasonable'. Flash drives which actually do distribute wear across the whole drive no matter what your write pattern is are considerably more expensive. As a general rule, if it's a cheap USB flash key, it's built using MLC flash chips (only about 10K erase/write cycles per erase block), is slow (MLC is slow), and implements a fancy form of defect remapping rather than real wear leveling.

The problem a lot of people have is that they hear about the concept of wear leveling and then assume it's cheap and easy to implement properly, since it sounds so simple. It's not. Try thinking about how you actually have to do it sometime. For example, how do you store the table or list which maps logical sectors to physical sectors? That alone is a very thorny problem, because if you store it in some of the physical sectors, you have to make the table itself subject to the wear-leveling algorithm, as the table is going to be the most frequently-written data of all. So you end up needing to store the table (and probably user data too) using some kind of log-structured file system. Now you have to chase pointers just to figure out where user data is located, and as high-density flash is not quite as random-access as people sometimes think it is (it's very oriented towards reading/writing large blocks rather than random access to individual bytes), you'd better have a controller with a lot of RAM so you can cache large chunks of the table; otherwise performance goes in the toilet.

TLDR version: true wear-leveling flash disk controllers tend to need lots of RAM and/or a second nonvolatile solid state memory with better lifespan than the main flash array. These things are expensive and therefore not found in most flash drives other than the SSDs built to the same form factor as hard disks.

Umm .. MRAM anybody?

[djtachyon]

I just received some samples of military grade MRAM recently. 4MB, "infinite" writes, "infinite" lifetime, -55C - 125C operating range, lower power than DRAM, and 35ns cycle times.

Fairchild has been making MRAM for awhile now.

http://en.wikipedia.org/wiki/MRAM

Re:Read / write cycles

[courteaudotbiz]

Of course, if wear leveling was performed perfectly, then pretty much the entire array would fail at once, right?

I have 4 wheels bearings on my Chrysler, and even though all of my wheels rotate with a perfect synchronism, only one of my bearings fails at a time, and the other ones don't follow ther brother in the next few miles...

Remember that at this scale, only an atom of difference could make some of those individual bits fail a year before the other...

What's the "Stick it in a Drawer" lifespan?

[RailRide]

All I've heard so far is debate on how long flash RAM will last while being constantly thrashed with read/write cycles. But what I'd like to know is how long data can be expected to remain intact on a typical flash drive that you just throw a bunch of files on and subsequently stick in a drawer and forget about, or at very least infrequently read from.

I keep a lot of files (mostly art projects) backed up on 2 or 3 seperate hard drives, but while any current project is progress, they tend to reside on a flash drive. Oh, they get rewritten to a couple of dozen times between scanning and completion, but once complete (and backed up) I tend to just leave the project folder on the drive, and when the drive gets close to filling up, I stick it in a drawer and buy another one. Should I expect to be able to call those "retired" drives backups as well, or will the integrity of the data likely deteriorate after a few years like a late model 3.5" floppy

---PCJ