Slashdot Mirror
Magnetic RAM from IBM
n8willis writes "ZDNet has an article about IBM's latest breakthrough, Magnetic RAM (MRAM) that actually works. The story is a bit fluffy, rolling out every possible buzzword (eg, wireless video will now be feasible due to faster RAM technology???), but the tech - in development since 1974 - is indeed going into production as we speak. Gotta hand it to IBM these days: copper interconnects, 200ppi LCD monitors and now this." I'll believe it when I can read/write from it.
Magnetic RAM, MRAM, is a non volatile memory with unlimited read and write cycles. It also has the potential
...being refreshed over 15,000 times per second!
to be very fast, and very dense.
Virtually all products that involve digital electronics (which includes just about everything these days: computers,
cellular phones, but also household appliances like washers, dryers, microwave ovens, refrigerators, and entertainment
devices like televisions, CD players, VCR's...) need memory. The choice of memory has historically involved a tradeoff.
Non volatile memories (memories that hold the information whether or not power is supplied) like EEPROM's can be
expensive and may have long term reliability problems - you can read and write to them only so many times or cycles
before you degrade the ability of the memory to "remember".
Volatile memories (memories that hold the information only if power is supplied) can be static RAM's or dynamic RAM's.
SRAM's (static RAM's) consume a lot less power than DRAM'S (dynamic RAM's), but take up a lot more chip area for a
given memory size, so are a lot more expensive. Because cost is generally the driving force in electronics, DRAM's
tend to have the highest volume of sales...they are the lowest cost, but consume a lot more power. In fact, to get the
density in a DRAM, we use a simple capacitor as the memory device. A charge on the capacitor can represent a "1"
and no charge can represent a "0". However, over time, the charge leaks off....losing all the information. To avoid this,
the DRAM must be REFRESHED. Essentially, a REFRESH cycle involves reading all the information out, and then putting it
all back in. Looking at a data sheet for a DRAM, the example has the 64 Meg DRAM needing to be refreshed every 64
msec
That refresh cycle on the DRAM explains the much greater power consumption of the less expensive DRAM compared
to the more expensive SRAM. While it may not be typical, a quick browsing through data sheets found a 64 M DRAM
that consumed 1 Watt of power, and a 64 M SRAM that consumed less than 400 mW.
An MRAM can have the density of a DRAM...and since cost goes with density, it is possible that an MRAM can have a
cost that is competitive with a DRAM...but it will have much lower power consumption...effectively zero power
consumption in the standby mode, which is the mode the memory spends most of its time in.
The MRAM doesn't require the refresh of a DRAM, and has the nonvolatility of a EEPROM, but has reliability superior to
the EEPROM. So, an MRAM may be able to replace DRAM's, SRAM's. amd EEPROM's, without involving any major
compromise or tradeoff.
It is hard to judge the improvement in the battery life of a cellular phone. With digital cellular phones used just
sporadically for voice phone calls, the battery life now is very good, but might perhaps be doubled with an MRAM - this
is just my guess, and may be way off. If the digital cellular phone is heavily used for phone calls, the power
consumption involved in sending the signal out would tend to dominate over the impact of improved power
consumption in the memory, and the impact on battery life might be minimal.
However, future applications of wireless products like the cellular phone include adding more functionality beyond
voice calls. For communication products, MRAM may make it possible to have access to the internet with the ability to
get video in addition to data and voice.
IBM recently announced their astonishing, new, unprecedented breakthrough in MAGNETIC memory that ACTUALLY WORKS, (some old industry wags are referring to it as core, for some unknown reason). Shortly afterward, they announced a startling new breakthrough method of storing data by punching holes in cards, a development no doubt inspired by the efficient vote tabulations in Florida.
include $sig;
1;
Most electronics up until now work within the charge domain. That is, devices all deal with moving, changing, transferring, etc, electric charge and the lack of electric charge. Amplifiers, for instance, can amplify current, which is the flow of charge, or voltage, which is the energy/charge ratio. Semiconductors exploit all kinds of funky physics to do these things.
However, there's a whole other degree of freedom of the electron that's virtually unused. Spin. In any elementary quantum mechanics course you'll learn rather soon on that electrons are Fermions with total spin 1/2, which means there are two spin states an electron can be in, usually called spin-up and spin-down.
So the new world of spintronics aims at manipulating the spin of the electrons, instead of the charge. Spin is a different beast than charge, in that it can be manipulated by magnetic fields and light, in vastly-different ways than does charge flow. Spin is a fundamental nature of angular momentum, so whereby the total charge is conserved within a small sample, so too is the angular momentum.
Some of these MRAM's were specifically mentioned yesterday, in that the parity of the spin can be used to store bits. One nice fact about this could be that information isn't lost if power is turned off, unlike DRAM's and many SRAM's.
It's a VERY new field, spintronics. I did a search on Google last night for only 'spintronics' and only 665 sites were listed. It's been around for a few years so far, but there have been problems with finding the right magnetic materials. You need the right combination of ferromagnetic and antiferromagnetic layers, and certain ways to test materials, before you can really start doing some good stuff. However, materials are starting to be found, so it's an exciting time for this potentially huge field.
Hopefully soon there'll be spin-like transistors, leading to spin amplifiers, and all sorts of other goodies. Sorry I don't have any specifics about this, but I just found out about it yesterday.
make world, not war
>>Here's an article from Scientific American on the topic.
Which points out that the data density wasn't there, and that they were slow and expensive. Commercially available isn't what we're looking for: commercially viable is, and Honeywell's product clearly wasn't. Admittedly, it doesn't sound like IBM is going to be able to make them cheaply for quite some time either, but at least they have the access times down (or so it sounds--the article was a bit vague, as is ZDnet's want).
High-speed Road Trip (18.000KPH)
Here's an article from Scientific American on the topic.
--
--
You are a fucking moron.