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A Magnetic Memory Alternative to Hard Disk
Dr Occult writes "Finally, a magnetic memory chip has been manufactured in volume and released by the U.S. company Freescale. Christened MRAM (magnetoresistive random-access memory),this chip will hold information even after power has been switched off. From the BBC news article: 'Unlike flash memory, which also can keep data without power, Mram has faster read and write speeds and does not degrade over time,' and 'MRAM chips could one day be used in PCs to store an operating system, allowing computers to start up faster when switched on.'"
Information about the product from the Freescale Press Release
It will be a while before they get their $25 / 4 megabit wholesale price to anywhere close to reasonable.0 4801944-v71_ITCad7JIwzqJZ_nfN_pacDg_20060809.html? mod=tff_main_tff_top
http://online.wsj.com/public/article/SB1152491713
_Today_ they are larger. But tomorrow Freescale
plans to shrink their new chips (29nm) under the
scales of the future standard 6T-SRAMs (still 45nm).
http://www.heise.de/newsticker/meldung/75243
First: freescale aims on the usage of MRAM in embeddet devices and microcontrollers. There will be no MRAM-Harddisk next month in the shops. 2nd: There is not only Freescale. Micromem will produce MRAM-Chips for the Aerospace industry. And IBM/Infineon already have an 16-MBit-MRAM-Chip since last year. There are also Renesas/Toshiba in the race. It's a completely new tech, you heard about years ago, when the first theories about mram came from the labs. But such a thing needs everytime many years to go to the serial production lines.
Freescale's MRAM technology isn't all that new...it's an old Motorola technology that they kept running with when they were spun off. It's taken them a few years to get going again, but it's already been done for a while.
That said, MRAM ain't a HD replacement yet. No one outside the aerospace industry is using it for storage right now that I'm aware of, and even if someone was, making a large enough FRAM based drive with 4Mb chips is HARD. 2 chips for every MB. 2048 chips for every GB. a 500GB FRAM disk would require 1,024,000 of these chips, requiring nearly 2,500 sqft of PCB space, and more power than a pile of overclocked P4s (~9mA * 3.3V * 1,024,000 chips = 30.4128kW at IDLE). Even if someone could build that, it'd be farking huge, run inconcievably hot, be incredibly power hungry, and sell for an obscenely expensive price, even for the most extr33m gadget hunters.
Wait for 32 and 64Mb chips. Then we'll talk.
Right now I'm too busy working with a serial FRAM from Ramtron to write more.
This is not a sig. this is a duck. quack.
- as fast as SRAM (i.e. cache in your processor)
- as small (i.e. as hight density) as DRAM; single MRAM memory cell is two magnets instead of two conductors of capacitor in DRAM, but the (theoretical) size is of the same order of magnitude
- non-volatile like Flash, but with random access and orders of magnitude faster, w/o "write penalty" and w/o erase/write cycles limit
- much less energy-hungry than SRAM, DRAM and Flash while working; when not working it can keep information at least as well as Flash
It's in development since the eighties and it will take time before we "get there" but it is possible, that one day MRAM could replace cache, main memory and memory cards in our computers.When? I have no idea, but AFAIR transistors didn't get from prototype to 65nm in a decade. Hopefully engineergs and managers in some semiconductor companies have longer attention span than an avarage slashdot reader.
Robert
Bastard Operator From 193.219.28.162
so we're looking at 'about' 3 inches for 16meg (in this case)
Bzzzzt. Wrong. Thank you for playing.
OK. You are half-right. It would be expensive to crate an "MRAM hard drive." So, getting 20 gigs of MRAM would cost a small fortune. But this is NOT a "pump-n-dump." This is really cool stuff. I can easily imagine some embedded systems that could really use this stuff. This is non-volatile system memory. The problem with FLASH and EEPROM memory is that the cells wear out after a lot of writing (somewhere in the neighborhood of 10,000 to 1,000,000 write cycles will give you trouble). For some applications, this is not enough, so you have to resort to battery-backed SRAM. Now there is at least another option.
- Do you need to store data without having a constant battery backup?
- Do you need to store a relatively small amount?
- Will the data be changing rapidly enough to kill a FLASH in short order?
- Would a hard drive be too big or too power hungry?
If you answered "yes" to all those questions, MRAM might be for you:Although, really, this seems to solve the exact same problem as Phase-Change RAM.
"-1 Troll" is the apparently the same as "-1 I disagree with you."
MRAM is in some ways a modern take on 1960's era "Core Memory" technology. There are similarities between both, however core memory was not semiconductor-based--it was a plane of copper wires woven together with little ferrite rings strung on where wires intersected. As such is is pretty low density: 16 Kbit of core memory took up 250 cm^2 of area. With MRAM the method of operation is the same and it also involves reversing polarity of magnetic fields. However there are no ferrite cores; MRAM consists of a sandwich of conductor grids around memory cells. Like with core memory an entire row of a grid can be written to in one operation--you charge one "row" line on the write grid and all the columns you want to flip and they all change at once.
Reading MRAM is simpler than core memory becasue core memory had no read operation--it had "flip to zero" and "flip to one" and a "sense" line--the sense line would emit a pulse if a core element changed state. To read core memory, you had to do a "flip to zero" and watch the sense line--if it pulsed then a one was in the cell and you had to do a "flip to one" to restore it. If there was no pulse then it was already zero. With MRAM reading simply involves measuring the resistance of the insulating layer of a memory cell (the insulating material has the property where resistance increases as the magnetic field passing through it increases). IIRC there is nothing preventing parallel reads either. MRAMs are also much denser--megabits can fit in 0.25 cm^2
The "MRAM hard drive" thing may be hyperbole right now, but it looks like development of MRAM rechnology is significantly outpacing Moores Law. MRAM is also potentially as fast as SRAM and as dense as SDRAM--without the need for refresh circuitry so designs can be greatly simplified. Further downsizing could make it a good flash replacement. The biggest hurdle could be reduction...
Here it is.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
It lost its data the moment you read it if the read/modify/write circuitry failed. Anyone remember the PDP-8, whose accumulator cleared when you read it, presumably so if it was implemented in core, there would not be a wasted rewrite cycle if you didn't need the accumulator data again? Ah, the fun of early machines...and you could even use them in IBMs, which is more than you can do with a P4.
Pining for the fjords
How much of a myth is it when you use least common denominator, portable file systems like FAT?
A decent flash disk will have write-spreading as a layer on top of the filesystem, so it will remap sectors on the fly to avoid wearout.