Slashdot Mirror
'Universal' Memory Aims To Replace Flash/DRAM
siliconbits writes "A single 'universal' memory technology that combines the speed of DRAM with the non-volatility and density of flash memory was recently invented at North Carolina State University, according to researchers. The new memory technology, which uses a double floating-gate field-effect-transistor, should enable computers to power down memories not currently being accessed, drastically cutting the energy consumed by computers of all types, from mobile and desktop computers to server farms and data centers, the researchers say."
This technology always seems to be less than 10 years away.
It will still have to come in 2 formats, I assume. One for RAM use and one for USB.
Volatility is actually useful for certain security policies: like storing sensitive passwords in computer memory and working with temporarily decrypted files.
Go NC State!
I want memristors.
though it had a short refresh time spec, would actually hold nearly all the bits for up to a minute, and we made early "digital" cameras out of them, charging up all the bits and letting light discharge the lit up pixels quicker than the others. It was a bit of a bear to figure out the pixel layout -- it wasn't in order, but we did it and even got to two bits or so per pixel resolution by taking more than one shot after a charge, different exposure times. One wonders why someone doesn't just work along those lines. Seems to me for most uses simply increasing the refresh time interval would save tons of power, and also complexity. If you could get it to a couple of days, I'd think that would be fine for most all portable devices, and you'd just use cheap flash as the disk, like now. I am guessing you'd lose some density, as the older, less dense DRAMs had large cells that stored more charge per bit, and that new lower voltage semis are also leakier, but it might be worth looking into anyway. I recall one case where the company I worked for designed some very early disk cache controllers. Well, actually I did about 90% of that. We used DRAM, but simply arranged the code so the basic idling operation (for example, looking for io requests or sorting the cache lookup table) took care of refresh anyway, wasn't too hard at all to manage that, and of course a block read or write always did a full page refresh. Made the thing a little bit faster, as there was never a conflict between refresh and real use in the bargain. This would also be trivial an any current opsys to get done. Probably happens by accident except in real pathological cases.
Why guess when you can know? Measure!
"We believe our new memory device will enable power-proportional computing, by allowing memory to be turned off during periods of low use without affecting performance," said Franzon.
Huh! A new chapter opens in the "program/OS optimization" - heap fragmentation will have an impact on the power your computer consumes, even when not swapping (assuming the high density and non-volatility will render HDD obsolete... a "no more swapping, everything is non-volatile-RAM, with constant addressing cost" becomes plausible).
Questions raise, answers kill. Raise questions to stay alive.
The memory breakthrough was working on had the speed of flash and the volatility of DRAM. It was pretty dense though...
Program Intellivision!
- OSses are not designed with this type memory in mind
Don't worry, I'm sure some kid in a basement somewhere is working on a FUSE driver.
Isn't this a dupe? I thought I saw it last week.
Actually, don't I see this same article _every_ week?
usb is high on cpu io there are much better buses to use.
I don't think the intent is to replace main memory, though. The benefits to two-tier storage like this is actually quite significant. A sizable percentage of disk writes don't ever get flushed to disk because they are temporary files.
Combine a smart OS that uses the first tier for write caching and the second tier for permanent storage, you'd be able to significantly reduce wear (assuming, of course, that there is a wear problem with these things as there is with flash parts). Assuming you use a smart controller to flush recent dirty bits to disk if the power gets cut before the OS shuts down the disk correctly, beyond the obvious changes in disk caching, it wouldn't require significant OS changes to use these parts like that, and it would be quite useful, both in terms of disk performance, reliability, and data integrity.
Check out my sci-fi/humor trilogy at PatriotsBooks.
"advertized"? Is that like a lazer?
Have you wever counted how often you need to reboot a computer?
About three times per year for me. (Debian lenny ppc)
Where does it get the power for the non-volatile write? It would have to have a battery or capacitor built in, in case of sudden loss of power. It would also need low voltage detection for the same reason. How does all of this end up affecting the cost and density? We already have non-volatile SRAM based on the same principles (warning: article sounds like it was lifted from a press release).
The reason we use DRAM as computer memory is because it's really, really cheap. If nvDRAM ends up having a significantly highly cost per byte, I doubt it'll see much use. Especially when one considers the ever-falling price point for solid-state drives.
Let's just call it nested memory. kthx.
I'm still waiting for it.
Let me show you my thing; it's the most advanced on the planet.
So it's time to think about the next step: overwrite before freeing memory.
I don't worry at all, it becomes a software problem, not a hardware problem. If only everyone overwrote unused memory...
...does it run Linux? ;-D
Rudd-O - http://rudd-o.com/
Whatever year it it comes to market, you can be sure of one thing....
That will be the year of Multics on the desktop.
I don't therefore I'm not.
Background storage, even FLASH, is far larger than main memory for a reason
That reason is that main memory is more expensive, is volatile, and requires power at all times. If that's no longer true, perhaps it's time to revisit the older designs where the storage and the memory were the same thing.
OSses are not designed with this type memory in mind
And they don't have to be if the BIOS zeros it on boot. However, there are substantial advantages to be had if they DO take advantage. For example the suspend states become much simpler.
At the same time, there are OSes that ARE designed this way. Currently, they use disk backed memory, but would be quite happy to just commit RAM to the flash.
- Have you wever counted how often you need to reboot a computer? WTF is this thing going to help?
See comment on simplified suspend state.
It's not cycle tested yet, but there is good reason to believe it will have a longer life than flash.
I don't see the density problem, flash seems to do OK now at that density.
It looks like the write to non-volatile should be lower energy than flash.
It's not a product in production yet and it may or may not work out, but it's not quite as dismal as you make it out to be.
I think memristors sound a lot more usable than this setup.
Given the other thoughts about heap fragmentation and such things, I don't know if it's reasonable to expect fine-grained "flush to NV and stop refreshing" application, but rather as a system-sleep sort of mechanism. Of course, if memory allocators and GCs are written in knowledge of keeping LRU data clumped together, it might be reasonable. The comments say flushing is done on a "line by line" basis, which I don't personally know how big or small that gets.
One wonders exactly how much juice it takes to flush to NV, vs the standard draw of the DRAM-style mode of operation.
Maybe in mobile sector 1W per SDRAM module is interesting, but on desktop computers it isn't. They should reduce the energy to keep ATX boxes switched off(!) to 0W, as it was with AT, where a mechanical switch was used to cut the PC from power. It is simply inacceptable to consume energy (usually over 5W) when something is completely down (yeah I know, there is wake-on-LAN etc, but 99% of people don't use it). That's why I have a big fat red switch on my multi-outlet power strip.
The memory market place was too much drama (teehee) in the end. At least now we can hope for some economies of scale, which will hopefully be passed on to consumers.
What does this mean to users? There's no new functionality. It's more or less "combined" existing functionality.
So, what is the significance here (I'm honestly asking, I'm sure there is some interesting consumer benefits).
A few I can think of:
1) Longer battery life on mobile devices
2) Instant "on", since the state of the OS and applications can remain in memory
With #2 I would guess that certain programs that maintain clock pulse counters may operate "oddly" and have to be reprogrammed to stay in sync. Though, I'm sure there would be some kind of "memory going to / returning from virtual back burner" interrupt.
Another implication I can think of is user security. Shutting down the computer may not be enough in the same manner that "emptying your recycling bin" does not physically remove the data. Hopefully this memory / flash is easy to wipe, and it would probably be partitioned into "working / ram memory" and "storage".
If - but that seems a pretty gigantic if to me.
It's *very* common with speed/price/size tradeoffs in engineering, regardless of which technology choosen. Usually, "pick any 2" is what it boils down to.
Sure, in principle, if you invent something that scores well on all 3 axes, then no trade-off is nessecary and all the older systems that score poorly on atleast one of the 3 axis, are obsolete. But I'm not holding my breath.
For storing large amounts of data for a long time, you want huge and cheap, but need little speed. For the registers in your CPU, the opposite is the case, you want all the speed you can possibly get, yet the amount of storage is very limited.
As you say, it's a trade off. If it's strong enough on 2 axis and not so bad on the other, it might be enough, at least for some application. After all, the pick 2 rule applies to everything we use now as well.
We already have a trend to using flash as storage (it's all the rage!), so it's not exactly a huge leap to imagine this catching on if it's decently priced and really is more durable.
The universal memory would have the speed of SRAM, the density of Flash, would write directly into the non-volatile memory (i.e. no extra nonvolatile storage step, and certainly no need to refresh), and would have the same price per bit as hard disks. That way you could it use in cache (SRAM speed), as DRAM replacement (beats DRAM in any category) and as hard disk replacement (nonvolatile, cheap).
This "universal" memory would be unsuitable for cache memory, thus it isn't universal.
The Tao of math: The numbers you can count are not the real numbers.
This shows more promise to replace SSD/NAND flash if it's more durable. I have my doubts about it being able to replace SDRAM in a desktop/server system except maybe laptops and mobile phone type devices (where power saving is more important than performace.) In a server, the memory is hardly idle, so any power saving would only be applied to completely idle equipment (eg wasted money to begin with.) Desktops can hibernate to such a device as secondary storage for power saving, but again, in a performance system, no memory would be wasted to begin with.
- Background storage, even FLASH, is far larger than main memory for a reason
What does this have to do with anything?
OSses are not designed with this type memory in mind
The only possible problem any current OS could have with this is this:
Have you wever counted how often you need to reboot a computer? WTF is this thing going to help?
...which could easily be solved by a BIOS tweak. Empty RAM on powerup. Problem solved.
Density will be far lower than DRAM, causing significantly higher prices and preventing it from competing. Also more complex cells are inherently more expensive and less reliable
Yeah that's why we're all still using EEPROMs and 5 1/4 floppies. Those hard drives the size of microwave ovens are just too damn expensive.
An "emergency flash write" still takes a lot of time and energy, at least partially invalidating the concept
And how often do you do anything like this with current storage technologies?
"When information is power, privacy is freedom" - Jah-Wren Ryel
About damn time. Now update the antiquated I/O systems found in "modern" computers, get rid of legacy technology, redesign a computer to move away from "a big mostly empty box with a few circuit boards", get rid of spinning platters as a form of data storage, and you might call today's computers "advanced" technology.
One to utterly wipe RAM... No, encrypting RAM is not an alternative, unless you really enjoy having your system, with the power of a supercomputer of 15 years ago, move with the speed of a *whizbang* 8088....
mark
Especially not the technically competent ones.
I was reading the technical specs on the Z80 recently, and the Zilog designers were brilliant in their CPU design which automatically refreshed the dynamic ram by using a self incrementing "R" register to traverse enough addresses to do the full refresh. That was back in the late 70's and 80's, and that more or less the same dynamic ram is with us still. We could use some advances in that area. It seems like we are struggling to find the elegant memory solution. When I started with computers, we were writing into a core to sense it's state then having to write the information back. That was clever, but inefficient. Now we have dynamic memory that wants to go to sleep, and we have to nudge it regularly to keep it awake. I hope in my lifetime we finally see a memory technology that is actually straightforward and elegant.
We could call it prescient memory, and it could recall data from the future as well as the past. You wouldn't even have to write the data into it, or give it the address of the data you want because it knows what you want before you ask.
I worked at a memory company who's name rhymes with Licron for over 10 years and about 8 years ago we were working on something similar to this. It was basically high speed NOR flash memory, but the project didn't get much traction in lieu of ramping up on DDRDRAM and Rambus DRAM memory production. Given the fact that DRAM production is an almost completely money losing venture you'd think memory companies like Infineon, Hynix, and Samsung would be pushing this technology a bit more aggressively.
I got here through a series of tubes
I didn't know they axed duplicates now..
"Memory On Demand" Cuts Energy Use
Posted by CmdrTaco on Wednesday January 26, @09:00AM
from the cut-it-off dept.
judgecorp writes
"Researchers are testing memory that can be powered down when not in use. This could slash the power used by computer memory, combining the benefits of DRAM (speed) and Flash (low power, non-volatile). The memory could also allow "instant-on" computers, according to an IEEE Computer Society report of the research at Carolina State University."
Read More
http://it.slashdot.org/story/11/01/26/1342246/Memory-On-Demand-Cuts-Energy-Use