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Memristor — 4th Basic Element of Circuits
Posted by
ScuttleMonkey
on Wed Apr 30, 2008 05:27 PM
from the old-meets-new dept.
from the old-meets-new dept.
esocid writes "Researchers at HP Labs have solved a decades-old mystery by proving the existence of a fourth basic element in integrated circuits that could make it possible to develop computers that turn on and off like an electric light. The memristor — short for memory resistor — could make it possible to develop far more energy-efficient computing systems with memories that retain information even after the power is off, so there's no wait for the system to boot up after turning the computer on. It may even be possible to create systems with some of the pattern-matching abilities of the human brain. Leon Chua, a distinguished faculty member at the University of California at Berkeley, initially theorized about and named the element in an academic paper published 37 years ago. Chua argued that the memristor was the fourth fundamental circuit element, along with the resistor, capacitor and inductor, and that it had properties that could not be duplicated by any combination of the other three elements."
Related Stories
[+]
Memristor Based RAM Could Be Out By 2009 142 comments
neural.disruption writes "According to the EETimes, HP is announcing that it 'plans to unveil RRAM prototype chips based on memristors with crossbar arrays in 2009.' I don't know if you remember the earlier story about HP Labs proving the existence of the Memristor that had been predicted in 1971 by Leon Chua, and has the nice property of maintaining a memory of the current that passes by it. This could bring us a new type of small non-volatile high-speed RAM at low cost because of the low complexity of the mechanism employed."
[+]
HP Creates First Hybrid Memristor Chip 155 comments
An anonymous reader writes "HP researchers have built the first functioning hybrid memristor-transistor chip. Lead researcher Stanley Williams and his team built the very first memristor — the '4th fundamental element' of integrated circuits after resistors, capacitors and inductors — back in April. Memristors can remember their resistance, leading to novel electronic capabilities. The new FPGA circuit uses memristors to perform tasks normally carried out by (many more) transistors and is therefore smaller, more power efficient and cheaper to make, HP says. Memristors could also turn out to be a more compact, faster alternative to flash memory."
[+]
New Memristor Makes Low-Cost, High-Density Memory 86 comments
KentuckyFC writes "A group of electronics engineers have discovered that a thin layer of vanadium oxide acts as a memristor, the fourth basic component of circuits after resistors, capacitors, and inductors that was discovered last year. At a critical temperature, a current passing through the layer causes it to change from an insulating state to a metal-like state, thereby changing its resistance (abstract). The effect lasts many hours — which is what makes the layer a memristor (a resistor with memory). The team says this could be scaled up to make resistive random access memory, or RRAM, at very low cost, from little more than layers of vanadium oxide."
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Great! (Score:2, Funny)
Just like a human brain? (Score:5, Funny)
As far as I know, human brains don't retain much information when the power is turned off and there's usually some trouble after the power is restored. Furthermore, I'm not sure how power-down information retention relates to pattern-matching abilities.
But what to I know, I had my brain off last night.
Re: (Score:2)
It's sort of difficult to restore power to that type of powering off of the brain. And when you do, I hear that the host's diet dramatically changes [theonion.com].
Re:Just like a human brain? (Score:5, Funny)
No, I meant my brain was really OFF. I'm a Zombie.
[ Where did you say you lived? ]
Parent
To call it the forth element... (Score:2, Insightful)
Basically you have Ohm's law which is v =Ri. There is a component for each variable: Capacitors for voltage, inductors for current, resistors for resistance. It is all there, in nice little differential equations.
Yes, this is a great discovery. But please stop with the sensationalist headlines. This is getting out of hand.
Re: (Score:2, Interesting)
Re:To call it the forth element... (Score:4, Informative)
Ohms law does not describe the basic componets of a circuit, it only provides a simply way to determine simple information about a simple circuit (Mainly a energy source, and a resistor). It has no room for capacitors or inductors. You need much higher math for that.
Parent
Re: (Score:3, Informative)
V = (R) i + (1/(s C)) i + (s L) i
This "memristor" is actually a function of the history of the electric flux going through the circuit:
V = M(q(t)) i, where M is the memristance
M(q(t)) = d Phi(t) / d q, where q is the electric charge particle
Phi = electric flux = integral of electric field E over an area A
Umm... what? (Score:2)
Re: (Score:2)
What a lame fifth element. There's not even a Leeloo.
From the paper itself (Score:5, Informative)
As for the others, they are components. For instance, a resistor R fits in dv = Rdi. A capacitor C fits in as dq = Cdv. An inductor as dphi = Ldi, and a memristor fills in the missing dphi = Mdq.
Parent
Re: (Score:2)
Re: (Score:3, Informative)
Instantaneously, a memristor behaves exactly like a resistor.
Tim.
Re:From the paper itself (Score:4, Interesting)
Maybe a Thixotropic [wikipedia.org] object like the viscocity of ketchup? It is an object that changes its resistance to flow over time with repect to the force of the flow that was previously applied.
The more force you apply to ketchup, the easier it is to pour. A memristor would be like the more electric flux you apply through the area of the device, the more/less resistance current will flow through the device.
-- Scott
Parent
Re: (Score:3, Informative)
For capacitors the equivalent law is i = C (dV/dt), and for inductors it's V = L (di/dt).
You can combine them all for an RLC circuit, but the result isn't Ohm's law.
Zero boot time (Score:2)
TRS-80 Color Computer, for example boots instantly since it runs from ROM unless you are using OS-9.
The TRS-80 Model 100 keeps its file system in RAM and has a separate NiCD to backup the RAM. It boots instantly. The backup lasts months in my experience (even today with old NiCd's).
And any computer can simply be left on... no boot time.
So there's nothing here that cannot be done with a m
I don't get it (Score:2)
Re: (Score:2)
The bizarre characterization of this as a discovery instead of an invention originates in the paper itself.
... on the flip side (Score:2)
Would this also inspire new forms of malware/viruses/trojans that persist in memory even after the system is powered off?
And another thing... forensic computer evidence. I guess you could sort of tell what the user was last doing before they turned off t
Re: (Score:2)
Doesn't matter.
If memory is settable -- and that is certainly a requirement -- then it's possible to set it all to zero at the flick of a switch. Hence, rebooting.
Also: it's possible to recover the state of current RAM a surprising amount of time after the user switched off the machine. (Well, okay, tens of seconds, at least).
I suppose if it became a problem you could always encrypt it on powerdown...
Reminds me of a joke... (Score:3, Funny)
The engineer wakes up and smells smoke. He goes out into the hallway and sees a fire, so he fills a trash can from his room with water and douses the fire. He goes back to bed.
Later, the physicist wakes up and smells smoke. He opens his door and sees a fire in the hallway. He walks down the hall to a fire hose and after calculating the flame velocity, distance, water pressure, trajectory, etc. extinguishes the fire with the minimum amount of water and energy needed.
Later, the mathematician wakes up and smells smoke. He goes to the hall, sees the fire and then the fire hose. He thinks for a moment and then exclaims, "Ah, a solution exists!" and then goes back to bed.
I'll admit I don't understand the classification (Score:3, Insightful)
Or maybe they're "basic" because every circuit (that's not superconducting), whether or not it contains semiconductors or more exotic stuff, has some amount resistance, capacitance, and inductance. Even if you don't want it, in which case you call it "parasitic". I don't think you're going to accidentally create two separate layers of titanium oxide.
So while I get why this discovery is totally awesome, I don't get what they mean by "fourth fundamental circuit element". Anyone got the skinny?
Re:I'll admit I don't understand the classificatio (Score:5, Informative)
A transistor may be approximated as a variable current source. Similarly, many applications of transistors are as "active" devices, which supply external power to the circuit being considered.
A diode is effectively nothing more than a voltage-controlled switch. In a DC circuit, it simply passes current through (with a small voltage drop that can be approximated by an inline negative voltage source).
Likewise, all transistors can be abstractly considered as networks of diodes. This is why they are inherently binary devices, and why computers "think" in binary.
The classical circuit elements (Resistor, Capacitor, Inductor) each fundamentally affect the electromagnetic properties of the electrons flowing through said circuit.
Resistors impede the flow of current; a capacitor is a current "bucket" that also blocks DC signals in AC circuits; and an inductor builds up a sort of inertia for the flow of current, through the creation of a magnetic field.
The distinction is hazy, but I think I can see it where it comes from.... when a diode/transistor does something, it affects of the "layout" of the circuit, rather than directly affecting the electrons flowing through it.
The memristor is extremely interesting, as it blurs the line between analogue components and solid-state devices, and provides exciting possibilities for the development of analogue computing and data storage.
Even more exciting is that they can already be made smaller than transistors, and two can be combined to create a device that functions analogous to a transistor.
Considering that we're quickly approaching the limits of Silicon-based technology, this invention may very well offer the key to the true "next generation" of electronic devices, and may very well be as significant to our generation as the transistor was to the previous. This is Nobel Prize-worthy stuff we're talking about.
Kudos to HP for supporting "true" R&D. They most definitely will be reaping the benefits of this one for years to come.
Parent
Re:I'll admit I don't understand the classificatio (Score:5, Informative)
There are four fundamental circuit variables; current, voltage, charge, and flux.
We can define the relationships between charge and current and between flux and voltage. (charge as an integral of current, flux as an integral of voltage over time)
A resistor provides a function to relate voltage and current.
A capacitor provides a function to relate charge and voltage.
An inductor provides a function to relate flux and current.
Until now we did not know how to construct a passive device which would provide a function relating charge and flux. The only remaining combination of these fundamental variables.
Parent
Re:I'll admit I don't understand the classificatio (Score:4, Informative)
Parent
Good news, everybody! (Score:2)
Another grand name from the creator of the finglonger.
"proved the existence" ?? (Score:2)
Repeat after me: the researchers constructed a membristor.
Somehow, I don't think these scientists really care about the abstract existence of memristors. Moreover, you can't prove the existence of something that didn't exist before you started. You might be able to proved the feasibility of such devices, but only in mathematics it may be appropriate to say you "proved the existence" of something when you actually have a construction.4 down, 1 to go... (Score:3, Funny)
the four fundamental elements (Score:2)
New Scientist link with some more information (Score:2, Informative)
This is very interesting stuff. I wonder if these will ever be produced for amateur use, or if they'll only ever find their way into DRAM and such..
Another link with yet more information (EETimes) (Score:2, Informative)
Call me old quaint (Score:2)
Re: (Score:3, Interesting)
Good: You're trying to recognize privacy problems.
Bad: You apparently don't understand the problem well enough to differentiate problems from non-problems.
More information (Score:2)
You'd think the article would link to it.
Advantage over Flash RAM? (Score:2)
Re: (Score:3, Insightful)
Insanely expensive prototypes with virtually no functionality in modern use, probably 4 to 10 years.
Re: (Score:3, Informative)
IBM discovered GMR and that was nearly universally used in hard drives within ten years.
Dangit... (Score:2)
analog memory (Score:5, Informative)
The other amazing thing about memristors is how small they are. The articles state that you can emulate a transistor by connecting a few memristors, and that transistor is smaller than any we have today. Also it states that the memristor actually performs better at smaller sizes. This really is neat stuff.
Parent
Re:The above post explains memristors well (Score:5, Interesting)
Given that this memristor looks like to be using very little power, can be scaled down very well and can be used both as storage and to build transistors - I'm pretty excited about this. Yeah, there are other attempts at non-volatile ram, but they are either slow (flash), cannot be written to many times (flash), expensive (a lot of flash alternatives) or just simply too energy consuming, the memristors should bring in some nice competition into the field, since the articles specifically state that it doesn't generate much heat at all, compared to currently existing other technologies, it can be made to change state faster than they could measure(!) in the lab and it can be repeated many times. So, the only part that is left is whether it is economically feasible to mass-produce these. I'm guessing it shouldn't be a very large problem either given the relative simplicity of this discovery.
Parent
Re:Leakage Current? (Score:4, Informative)
Parent
Re: (Score:3, Informative)
Most inexpensive chip processes involve using blue and UV light to effectively (with chemical baths and deposition treatments) etch the surface of the chip into the correct shape and size. The biggest limitation here is that the light is around 300nm. When you're working significantly smaller than that, etching with this light is not as effective. Using higher frequency light can break down the materials (bath
Re: (Score:3, Insightful)
I think where you're really going astray is in assuming that a system which doesn't typically need to perform a full reboot would somehow be incapable of doing so; you even imply OS developers might forget that's a requirement, which is a huge insult to every OS developer. Having a system be able to boot itself from a clean slate (as it would have to for a new install, replacement of memristor-RAM sticks etc.) is not only a blindingly obvious requirement, but code that would be required anyway to boot the
Re: (Score:3, Interesting)
A memristor only varies the resistivity from one of the wires, which effectively isolates the two circuits. This cannot be effectively be achieved with resistors, capacitors, or inductors. So, the memristor is actually a "resistivity transistor", which happens to have memory included.
A practical application for this would
Re: (Score:3, Informative)
You have described a bipolar transistor. However, with field effect transistors, there is no current between the gate (base) and the source/drain (collector/emitter). In the case of a bipolar transistor, the emitter/collector current is controlled by the base/emitter current, whereas the source/drain current of a FET is
Re:Sure, it's neat (Score:4, Funny)
Parent
Re: (Score:3, Funny)
*blink* *blink*
Re: (Score:2)
This article on wired's site talks about that: http://blog.wired.com/gadgets/2008/04/scientists-prov.html [wired.com]
In short - it's going to be a while
might, might, might, could, could, could (Score:3, Insightful)
We've had Non-volatile state storage for ages (eg. FeRAM and floating gates (as used in flash) and battery backed up RAM). State storage is only part of the picture.
W
Re: (Score:2)
They could still re-install.
-jcr