Category: Storage density

Computational (DNA) storage – end of evolution part 4

Posted on by Ray in Storage density, Strategic Inflection Points

We were at a recent Storage Field Day (SFD26) where there was a presentation on DNA storage, a new SNIA technical affiliate. The talk there was on how far DNA storage has come and is capable of easily storing GB of data. But I was perusing PNAS archives the other day and ran across an interesting paper Parallel molecular computation on digital data stored in DNA, essentially DNA computational storage.

Computational storage are storage devices (SSDs or HDDs) with computational cores that can be devoted to outside compute activities. Recently, these devices have taken over much of the hyper-scalar grunt work of video/audio transcoding and data encryption activities which are both computationally and data intensive activities.

DNA strand storage and computers

The article above discusses the use of DNA “strand displacement” interactions as micro-code instructions to enable computation on DNA strand storage. The use of DNA strands for storage reduces the storage density of DNA information that currently use nucleotides to encode bits (theoretically, 2 bits per nucleotide) to 0.03 bits per nucleotide. But as DNA information density (using nucleotides) is some 6 orders of magnitude greater than current optical or magnetic storage, this shouldn’t be a concern.

A bit is represented by 5 to 7 nucleotides in DNA strand storage, which they called a domain, these are grouped into a 4 or 5 bit cells, with one or more cells arranged in a DNA strand register which is stored on a DNA plasmid.

They used a common DNA plasmid (M13mp18, 7.2k bases long) for their storage ring (which had many registers on it). M13mp18 is capable of storing several hundred bits, but for their research they used it to store 9 DNA strand registers.

The article discusses the (wet) chemical computational methods necessary to realize DNA strand registers and programing that uses that storage.

The problem with current DNA storage devices is that read out is destructive and time consuming. With current DNA storage, data has to be read out and then computation occurs electronically and then new DNA has to be re-synthesized with any results that need to be stored.

With a computational DNA strand storage device, all this could be done in a single test tube, with no need to do any work outside the test tube.

How DNA strand computer works

They figure shows a multi cell DNA strand register, with nic’s or mismatched nucleotides representing the value of 0 or 1. They use these strands, nic’s and toeholds (attachment points) on DNA strands to represent data. They attach magnetic beads to the DNA strands for manipulation.

DNA strand displacement interactions or the micro-code instructions they have defined include

  • Attachment, where an instruction can be used to attach a cell of information to a register strand.
  • Displacement, where an instruction can be used used to displace an information cell in a register strand.
  • Detachment, where an instruction can be used to a cell present in a register strand to be detach it from the register.

Instructions are introduced, one at a time, as separate DNA strands, into the test tube holding the DNA strand registers. DNA strand data can be replicated 1000s or millions of times in a test tube and the instructions could be replicated as well allowing them to operate on all the DNA strands in the tube.

Creating a SIMD (single instruction stream operating on multiple data elements) computational device based on strand DNA storage which they call SIMDDNA. Note: GPUs and CPUs with vector instructions are also SIMD devices

Using these microcoded DNA strand instructions and DNA strand register storage, they have implemented a bit counter and a Turing Rule 110, sort of like life, program. Turing Rule 110 is Turing Complete and as such, can, with enough time and memory, simulate any program calculation. Later in the a paper they discuss their implementation of a random access device where they go in and retrieve a piece of data and erase it.

Program for bit counting, information in solid blue boundary are the instructions and information in dotted boundary are the impacts to the strand data.

The process seems to flow as follows, they add magnetic beads to each register strand, add an instruction at a time to the test tube, wait for it to complete, wash out the waste products and then add another. When all instructions have been executed the DNA strand computation is done and if needed, can be read out (destructively). Or perhaps pass off to the next program for processing. An instruction can take anywhere from 2 to 10 minutes to complete (it’s early yet in the technology).

They also indicated that the instruction bath added to the test tube need not contain all the same instructions which means that it could create a MIMD (multi-instruction stream operations on multiple data elements) computational device.

The results of the DNA strand computations weren’t 100% accurate but they show that it’s 70-80% accurate at the moment. And when DNA data strands are re-used, for subsequent programs, their accuracy goes down.

There are other approaches to DNA computation and storage which we discuss in parts-1, -2 and -3 in our End of Evolution series. And if you want to learn more about current DNA storage please check out the SFD26 SNIA videos or listen to our GBoS podcast with Dr. J Metz.

Where does evolution fit in

Evolution seems to operate on mutation of DNA and natural selection, or selection of the fittest. Over time this allows good mutations to accumulate and bad mutations to die off.

There’s a mechanism in digital computing called ECC (error correcting codes) which, for example, add additional “guard” bits to every 64-128 bit word of data in a computer memory and using the guard bits, is able to detect 2 or more bit errors (mutations) and correct 1 or 2 bit errors.

If one were to create an ECC algorithm for human DNA strands, say encoding DNA guard bits in junk DNA and an ECC algorithm in a DNA (strand)computer, and inject this into a newborn, the algorithm could periodically check the accuracy of any DNA information in every cell of a human body, and correct it, if there were any mutations. Thus ending human evolution.

We seem a ways off from doing any of this but I could see something like ECC being applied to a computational DNA strand storage device in a matter years. And getting this sort of functionality into a human cell maybe a decade or two. Getting it to the point where it could do this over a lifetime maybe another decade after that.

Comments?

Photo Credit(s):

  • Section B from Figure 2 in the paper
  • Figure 1 from the paper
  • Section A from Figure 2 in the paper
  • Section C from Figure 2 in the paper
  • Section A from Figure 3 in the paper

New PCM could supply 36PB of memory to CPUs

Posted on by Ray in Energy efficiency, Processing performance, R&D measures, Storage class memories, Storage density, Storage energy use, Storage performance

Read an article this past week on how quantum geometry can enable a new form of PCM (phase change memory) that is based on stacks of metallic layers (SciTech Daily article: Berry curvature memory: quantum geometry enables information storage in metallic layers), That article referred to a Nature article (Berry curvature memory through electrically driven stacking transitions) behind a paywall but I found a pre-print of it, Berry curvature memory through electrically driven stacking transitions.

Figure 1| Signatures of two different electrically-driven phase transitions in WTe2. a, Side view (b–c plane) of unit cell showing possible stacking orders in WTe2 (monoclinic 1T’, polar orthorhombic Td,↑ or Td,↓) and schematics of their Berry curvature distributions in momentum space. The spontaneous polarization and the Berry curvature dipole are labelled as P and D, respectively. The yellow spheres refer to W atoms while the black spheres represent Te atoms. b, Schematic of dual-gate h-BN capped WTe2 evice. c, Electrical conductance G with rectangular-shape hysteresis (labeled as Type I) induced by external doping at 80 K. Pure doping was applied following Vt/dt = Vb/db under a scan sequence indicated by black arrows. d, Electrical conductance G with butterfly-shape switching (labeled as Type II) driven by electric field at 80 K. Pure E field was applied following -Vt/dt = Vb/db under a scan sequence indicated by black arrows. Positive E⊥ is defined along +c axis. Based on the distinct hysteresis observations in c and d, two different phase transitions can be induced by different gating configurations.

The number one challenge in IT today,is that data just keeps growing. 2+ Exabytes today and much more tomorrow.

All that information takes storage, bandwidth and ultimately some form of computation to take advantage of it. While computation, bandwidth, and storage density all keep going up, at some point the energy required to read, write, transmit and compute over all these Exabytes of data will become a significant burden to the world.

PCM and other forms of NVM such as Intel’s Optane PMEM, have brought a step change in how much data can be stored close to server CPUs today. And as, Optane PMEM doesn’t require refresh, it has also reduced the energy required to store and sustain that data over DRAM. I have no doubt that density, energy consumption and performance will continue to improve for these devices over the coming years, if not decades.

In the mean time, researchers are actively pursuing different classes of material that could replace or improve on PCM with even less power, better performance and higher densities. Berry Curvature Memory is the first I’ve seen that has several significant advantages over PCM today.

Berry Curvature Memory (BCM)

I spent some time trying to gain an understanding of Berry Curvatures.. As much as I can gather it’s a quantum-mechanical geometric effect that quantifies the topological characteristics of the entanglement of electrons in a crystal. Suffice it to say, it’s something that can be measured as a elecro-magnetic field that provides phase transitions (on-off) in a metallic crystal at the topological level. 

In the case of BCM, they used three to five atomically thin, mono-layers of  WTe2 (Tungsten Ditelluride), a Type II  Weyl semi-metal that exhibits super conductivity, high magneto-resistance, and the ability to alter interlayer sliding through the use of terahertz (Thz) radiation. 

It appears that by using BCM in a memory, 

Fig. 4| Layer-parity selective Berry curvature memory behavior in Td,↑ to Td,↓ stacking transition. a,
The nonlinear Hall effect measurement schematics. An applied current flow along the a axis results in the generation of nonlinear Hall voltage along the b axis, proportional to the Berry curvature dipole strength at the Fermi level. b, Quadratic amplitude of nonlinear transverse voltage at 2ω as a function of longitudinal current at ω. c, d, Electric field dependent longitudinal conductance (upper figure) and nonlinear Hall signal (lower figure) in trilayer WTe2 and four-layer WTe2 respectively. Though similar butterfly-shape hysteresis in longitudinal conductance are observed, the sign of the nonlinear Hall signal was observed to be reversed in the trilayer while maintaining unchanged in the four-layer crystal. Because the nonlinear Hall signal (V⊥,2ω / (V//,ω)2 ) is proportional to Berry curvature dipole strength, it indicates the flipping of Berry curvature dipole only occurs in trilayer. e, Schematics of layer-parity selective symmetry operations effectively transforming Td,↑ to Td,↓. The interlayer sliding transition between these two ferroelectric stackings is equivalent to an inversion operation in odd layer while a mirror operation respect to the ab plane in even layer. f, g, Calculated Berry curvature Ωc distribution in 2D Brillouin zone at the Fermi level for Td,↑ and Td,↓ in trilayer and four-layer WTe2. The symmetry operation analysis and first principle calculations confirm Berry curvature and its dipole sign reversal in trilayer while invariant in four-layer, leading to the observed layer-parity selective nonlinear Hall memory behavior.
  • To alter a memory cell takes “a few meV/unit cell, two orders of magnitude less than conventional bond rearrangement in phase change materials” (PCM). Which in laymen’s terms says it takes 100X less energy to change a bit than PCM.
  • To alter a memory cell it uses terahertz radiation (Thz) this uses pulses of light or other electromagnetic radiation whose wavelength is on the order of picoseconds or less to change a memory cell. This is 1000X faster than other PCM that exist today.
  • To construct a BCM memory cell takes between 13 and 16  atoms of W and Te2 constructed of 3 to 5 layers of atomically thin, WTe2 semi-metal.

While it’s hard to see in the figure above, the way this memory works is that the inner layer slides left to right with respect to the picture and it’s this realignment of atoms between the three or five layers that give rise to the changes in the Berry Curvature phase space or provide on-off switching.

To get from the lab to product is a long road but the fact that it has density, energy and speed advantages measured in multiple orders of magnitude certainly bode well for it’s potential to disrupt current PCM technologies.

Potential problems with BCM

Nonetheless, even though it exhibits superior performance characteritics with respect to PCM, there are a number of possible issues that could limit it’s use.

One concern (on my part) is that the inner-layer sliding may induce some sort of fatigue. Although, I’ve heard that mechanical fatigue at the atomic level is not nearly as much of a concern as one sees in (> atomic scale and) larger structures. I must assume this would induce some stress and as such, limit the (Write cycles) endurance of BCM.

Another possible concern is how to shrink size of the Thz radiation required to only write a small area of the material. Yes one memory cell can be measured bi the width of 3 atoms, but the next question is how far away do I need to place the next memory cell. The laser used in BCM focused down to ~1.5 μm. At this size it’s 1,000X bigger than the BCM memory cell width (~1.5 nm).

Yet another potential problem is that current BCM must be embedded in a continuous flow of liquid nitrogen (@80K). Unclear how much of a requirement this temperature is for BCM to function. But there are no computers nowadays that require this level of cooling.

Figure 3| Td,↑ to Td,↓ stacking transitions with preserved crystal orientation in Type II hysteresis. a,
in-situ SHG intensity evolution in Type II phase transition, driven by a pure E field sweep on a four-layer and a five-layer Td-WTe2 devices (indicated by the arrows). Both show butterfly-shape SHG intensity hysteresis responses as a signature of ferroelectric switching between upward and downward polarization phases. The intensity minima at turning points in four-layer and five-layer crystals show significant difference in magnitude, consistent with the layer dependent SHG contrast in 1T’ stacking. This suggests changes in stacking structures take place during the Type II phase transition, which may involve 1T’ stacking as the intermediate state. b, Raman spectra of both interlayer and intralayer vibrations of fully poled upward and downward polarization phases in the 5L sample, showing nearly identical characteristic phonons of polar Td crystals. c, SHG intensity of fully poled upward and downward polarization phases as a function of analyzer polarization angle, with fixed incident polarization along p direction (or b axis). Both the polarization patterns and lobe orientations of these two phases are almost the same and can be well fitted based on the second order susceptibility matrix of Pm space group (Supplementary Information Section I). These observations reveal the transition between Td,↑ and Td,↓ stacking orders is the origin of
Type II phase transition, through which the crystal orientations are preserved.

Finally, from my perspective, can such a memory can be stacked vertically, with a higher number of layers. Yes there are three to five layers of the WTe2 used in BCM but can you put another three to five layers on top of that, and then another. Although the researchers used three, four and five layer configurations, it appears that although it changed the amplitude of the Berry Curvature effect, it didn’t seem to add more states to the transition.. If we were to more layers of WTe2 would we be able to discern say 16 different states (like QLC NAND today).

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So there’s a ways to go to productize BCM. But, aside from eliminating the low-temperature requirements, everything else looks pretty doable, at least to me.

I think it would open up a whole new dimension of applications, if we had say 60TB of memory to compute with, don’t you think?

Comments?

[Updated the title from 60TB to PB to 36PB as I understood how much memory PMEM can provide today…, the Eds.]

Photo Credit(s):

Research reveals ~liquid nitrogen temperature molecular magnets with 100X denser storage

Posted on by Ray in Data density, Disk storage, Storage density, Storage drive, Strategic Inflection Points, System effectiveness


Must be on a materials science binge these days. I read another article this week in Phys.org on “Major leap towards data storage at the molecular level” reporting on a Nature article “Molecular magnetic hysteresis at 60K“, where researchers from University of Manchester, led by Dr David Mills and Dr Nicholas Chilton from the School of Chemistry, have come up with a new material that provides molecular level magnetics at almost liquid nitrogen temperatures.

Previously, molecular magnets only operated at from 4 to 14K (degrees Kelvin) from research done over the last 25 years or so, but this new  research shows similar effects operating at ~60K or close to liquid nitrogen temperatures. Nitrogen freezes at 63K and boils at ~77K, and I would guess, is liquid somewhere between those temperatures.

What new material

The new material, “hexa-tert-butyldysprosocenium complex—[Dy(Cpttt)2][B(C6F5)4], with Cpttt = {C5H2tBu3-1,2,4} and tBu = C(CH3)3“, dysprosocenium for short was designed (?) by the researchers at Manchester and was shown to exhibit magnetism at the molecular level at 60K.

The storage effect is hysteresis, which is a materials ability to remember the last (magnetic/electrical/?) field it was exposed to and the magnetic field is measured in oersteds.

The researchers claim the new material provides magnetic hysteresis at a sweep level of 22 oersteds. Not sure what “sweep level of 22 oersteds” means but I assume a molecule of the material is magnetized with a field strength of 22 oersteds and retains this magnetic field over time.

Reports of disk’s death, have been greatly exaggerated

While there seems to be no end in sight for the densities of flash storage these days with 3D NAND (see my 3D NAND, how high can it go post or listen to our GBoS FMS2017 wrap-up with Jim Handy podcast), the disk industry lives on.

Disk industry researchers have been investigating HAMR, ([laser] heat assisted magnetic recording, see my Disk density hits new record … post) for some time now to increase disk storage density. But to my knowledge HAMR has not come out in any generally available disk device on the market yet. HAMR was supposed to provide the next big increase in disk storage densities.

Maybe they should be looking at CAMMR, or cold assisted magnetic molecular recording (heard it here, 1st).

According to Dr Chilton using the new material at 60K in a disk device would increase capacity by 100X. Western Digital just announced a 20TB MyBook Duo disk system for desktop storage and backup. With this new material, at 100X current densities, we could have 2PB Mybook Duo storage system on your desktop.

That should keep my ever increasing video-photo-music library in fine shape and everything else backed up for a little while longer.

Comments?

Photo Credit(s): Molecular magnetic hysteresis at 60K, Nature article

 

Nanterro emerges from stealth with CNT based NRAM

Posted on by Ray in data access, Distributed computing, Energy efficiency, Mobile computing, SSD storage, Storage density, Storage energy use, Storage performance, Strategic Inflection Points

512px-Types_of_Carbon_NanotubesNanterro just came out of stealth this week and bagged $31.5M in a Series E funding round. Apparently, Nanterro has been developing a new form of non-volatile RAM (NRAM), based on Carbon Nanotubes (CNT), which seems to work like an old T-bar switch, only in the NM sphere and using CNT for the wiring.

They were founded in 2001, and are finally  ready to emerge from stealth. Nanterro already has 175+ issued patents, with another 200 patents pending. The NRAM is currently in production at 7 CMOS fabs already and they are sampling 4Mb NRAM chips  to a number of customers.

NRAM vs. NAND

Performance of the NRAM is on a par with DRAM (~100 times faster than NAND), can be configured in 3D and supports MLC (multi-bits per cell) configurations.  NRAM also supports orders of magnitude more (assume they mean writes) accesses and stores data much longer than NAND.

The only question is the capacity, with shipping NAND on the order of 200Gb, NRAM is  about 2**14X behind NAND. Nanterre claims that their CNT-NRAM CMOS process can be scaled down to <5nm. Which is one or two generations below the current NAND scale factor and assuming they can pack as many bits in the same area, should be able to compete well with NAND.They claim that their NRAM technology is capable of Terabit capacities (assumed to be at the 5nm node).

The other nice thing is that Nanterro says the new NRAM uses less power than DRAM, which means that in addition to attaining higher capacities, DRAM like access times, it will also reduce power consumption.

It seems a natural for mobile applications. The press release claims it was already tested in space and there are customers looking at the technology for automobiles. The company claims the total addressable market is ~$170B USD. Which probably includes DRAM and NAND together.

CNT in CMOS chips?

Key to Nanterro’s technology was incorporating the use of CNT in CMOS processes, so that chips can be manufactured on current fab lines. It’s probably just the start of the use of CNT in electronic chips but it’s one that could potentially pay for the technology development many times over. CNT has a number of characteristics which would be beneficial to other electronic circuitry beyond NRAM.

How quickly they can ramp the capacity up from 4Mb seems to be a significant factor. Which is no doubt, why they went out for Series E funding.

So we have another new non-volatile memory technology.On the other hand, these guys seem to be a long ways away from the lab, with something that works today and the potential to go all the way down to 5nm.

It should interesting as the other NV technologies start to emerge to see which one generates sufficient market traction to succeed in the long run. Especially as NAND doesn’t seem to be slowing down much.

Comments?

Picture Credits: Wikimedia.com

Acoustic Assisted Magnetic Recording is invented

Posted on by Ray in Storage density

Read an article today about Acoustic Assisted Magnetic Recording (See Oregon State University article Researchers invent “acoustic-assisted magnetic recording”).

Just like heat assisted magnetic recording (HAMR, see our Disk density hits new record… post) which uses laser beams, acoustic assisted magnetic recording (AAMR) uses ultrasound to heat up a spot on media to help it be magnetized.

Why heat up media?

The problems with the extremely dense storage coming out of the labs these days is that the bits are becoming so small that’s it’s increasingly hard to insure that bits close by aren’t being disturbed when a bit is modified. This has led to an interest in shingled writes which we discussed in Sequential only disks and Shingled magnetic recorded disks posts.

But another possibility is to add heat to the process to isolate a bit on magnetic media. In this way a heated bit will be changed while its cooler neighbors are left alone.

I was at the dental hygenist the other day and she was using a new probe which used ultrasound to break up the plaque. In this case, it was also spewing water to cool the tip.  In any event, it appears as if ultrasound can be used to heat up, break stuff and image soft tissue, pretty versatile technology.

Is AAMR better than HAMR?

The nice thing about AAMR is that it can potentially be made with all solid state electronics and as such, wouldn’t require any optical componentry like HAMR.   So in the race against HAMR this could be a crucial edge and thus, could potentially be much easier to fabricate for use in tomorrows disk drives.

I foresee some possible problems with the technology, such as what is size of the heated spot and will the ultrasound emitter need any cooling (like the dental probe).

But it all seems like a reasonable and  logical extension of HAMR technologies being developed in labs today. Also, AAMR could quite probably could make use of the same thermally activated media developed for HAMR applications. Not having to come up with a new media formulation should help it get out of the lab even quicker. That is, if its other problems can be worked out.

In the post on HAMR, it had achieved a Tb/sqin in the lab, as the new media density high watermark.  As far as I could tell from the information published on AAMR, there were no new density records being discussed. However, if AAMR is able to achieve anything close to HAMR densities, we are in for larger capacity disk drives for another decade or so.

Comments?

Photo Credit: AAMR head assembly by Oregon State University

 

Super long term archive

Posted on by Ray in Data readability, Optical storage, Scenario planning, Storage, Storage density, Storage longevity

Read an article this past week in Scientific American about a new fused silica glass storage device from Hitachi Ltd., announced last September. The new media is recorded with lasers burning dots which represent binary one or leaving spaces which represents binary 0 onto the media.

As can be seen in the photos above, the data can readily be read by microscope which makes it pretty easy for some future civilization to read the binary data. However, knowing how to decode the binary data into pictures, documents and text is another matter entirely.

We have discussed the format problem before in our Today’s data and the 1000 year archive as well as Digital Rosetta stone vs. 3D barcodes posts. And this new technology would complete with the currently available, M-disc long term achive-able, DVD technology from Millenniata which we have also talked about before.

Semi-perpetual storage archive!!

Hitachi tested the new fused silica glass storage media at 1000C for several hours which they say indicates that it can survive several 100 million years without degradation. At this level it can provide a 300 million year storage archive (M-disc only claims 1000 years).   They are calling their new storage device, “semi-perpetual” storage.  If 100s of millions of years is semi-perpetual, I gotta wonder what perpetual storage might look like.

At CD recording density, with higher densities possible

They were able to achieve CD levels of recording density with a four layer approach. This amounted to about 40Mb/sqin.  While DVD technology is on the order of 330Mb/sqin and BlueRay is ~15Gb/sqin, but neither of these technologies claim even a million year lifetime.   Also, there is the possibility of even more layers so the 40Mb/sqin could double or quadruple potentially.

But data formats change every few years nowadays

My problem with all this is the data format issue, we will need something like a digital rosetta stone for every data format ever conceived in order to make this a practical digital storage device.

Alternatively we could plan to use it more like an analogue storage device, with something like a black and white or grey scale like photographs of  information to be retained imprinted in the media.  That way, a simple microscope could be used to see the photo image.  I suppose color photographs could be implemented using different plates per color, similar to four color magazine production processing. Texts could be handled by just taking a black and white photo of a document and printing them in the media.

According to a post I read about the size of the collection at the Library of Congress, they currently have about 3PB of digital data in their collections which in 650MB CD chunks would be about 4.6M CDs.  So if there is an intent to copy this data onto the new semi-perpetual storage media for the year 300,002012 we probably ought to start now.

Another tidbit to add to the discussion at last months Hitachi Data Systems Influencers Summit, HDS was showing off some of their recent lab work and they had an optical jukebox on display that they claimed would be used for long term archive. I get the feeling that maybe they plan to commercialize this technology soon – stay tuned for more

 

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Image: Hitachi.com website (c) 2012 Hitachi, Ltd.,

Disk density hits new record, 1Tb/sqin with HAMR

Posted on by Ray in Disk storage, Storage density, Strategic Inflection Points

Seagate has achieved 1Tb/sqin recording (source: http://www.gizmag.com)
Seagate has achieved 1Tb/sqin recording (source: http://www.gizmag.com)

Well I thought 36TB on my Mac was going to be enough.  Then along comes Seagate with this weeks announcement of reaching 1Tb/sqin (1 Trillion bits per square inch) using their new HAMR (heat assisted magnetic recording) technology.

Current LFF drive technology runs at about 620Gb/sqin providing a  3.5″ drive capacity of around 3TB or about 500Gb/sqin for 2.5″ drives supporting ~750GB.  The new 1Tb/sqin drives will easily double these capacities.

But the exciting part is that with the new HAMR or TAR (thermally assisted recording) heads and media, the long term potential is even brighter.  This new technology should be capable of 5 to 10Tb/sqin which means 3.5″ drives of 30 to 60TB and 2.5″ drives of 10 t0 20TB.

HAMR explained

HAMR uses both lasers and magnetic heads to record data in even smaller spaces than current PMR (perpendicular magnetic recording) or vertical recording heads do today.   You may recall that PMR was introduced in 2006 and now, just 6 years later we are already seeing the next generation head and media technologies in labs.

Denser disks requires smaller bits and with smaller bits disk technology runs into three problems readability, writeability and stability, AKA the magnetic recording trilemma.  Smaller bits require better stability, but better stability makes it much harder to write or change a bits magnetic orientation.  Enter the laser in HAMR, with laser heating the bits can become much more maleable.  These warmed bits can be more easily written bypassing the stability-writeability problem, at least for now.

However, just as in any big technology transition there are other competing ideas with the potential to win out.  One possibility we have discussed previously is shingled writes using bit patterned media (see my Sequential only disk post) but this requires a rethinking/re-architecting of disk storage.  As such, at best it’s an offshoot of today’s disk technology and at worst, it’s a slight detour on the overall technology roadmap.

Of course PMR is not going away any time soon. Other vendors (and proboblf Seagate) will continue to push PMR technology as far as it can go.  After all, it’s a proven technology, inside millions of spinning disks today.  But, according to Seagate, it can achieve 1Tb/sqin but go no further.

So when can I get HAMR disks

There was no mention in the press release as to when HAMR disks would be made available to the general public, but typically the drive industry has been doubling densities every 18 to 24 months.  Assuming they continue this trend across a head/media technology transition like HAMR, we should have those 6GB hard disk drives sometime around 2014, if not sooner.

HAMR technology will likely make it’s first appearance in 72oorpm drives.  Bigger capacities seem to always first come out in slower performing disks (see my Disk trends, revisited post)

HAMR performance wasn’t discussed in the Seagate press release, but with 2Mb per linear track inch and 15Krpm disk drives, the transfer rates would seem to need to be on the order of at least 850MB/sec at the OD (outer diameter) for read data transfers.

How quickly HAMR heads can write data is another matter. The fact that the laser heats the media before the magnetic head can write it seems to call for a magnetic-plus-optical head contraption where the laser is in front of the magnetics (see picture above).

How long it takes to heat the media to enable magnetization is one critical question in write performance. But this could potential be mitigated by the strength of the laser pulse and how far the  laser has to be in front of the recording head.

With all this talk of writing, there hasn’t been lots of discussion on read heads. I guess everyone’s assuming the current PMR read heads will do the trick, with a significant speed up of course, to handle the higher linear densities.

What’s next?

As for what comes after HAMR, checkout another post I did on using lasers to magnetize (write) data (see Magnetic storage using lasers alone).  The advantage of this new “laser-only” technology was a significant speed up in transfer speeds.  It seems to me that HAMR could easily be an intermediate step on the path to laser-only recording having both laser optics and magnetic recording/reading heads in one assembly.

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Lets see 6TB in 2014, 12TB in 2016 and 24TB in 2018, maybe I won’t need that WD Thunderbolt drive string as quickly as I thought.

Comments?

 

 

NSA’s huge (YBs) new data center to turn on in 2013

Posted on by Ray in Data index, data protection, Data security, Distributed computing, Information economy, Storage density, Strategic Inflection Points, System effectiveness

 

National_Security_Agency_seal
National_Security_Agency_seal

Ran across a story in Wired about the new NSA Utah data center today which is scheduled to be operational in September of 2013.

This new data center is intended to house copies of all communications intercepted the NSA.  We have talked about this data center before and how it’s going to store YB of data (See my Yottabytes by 2015?! post).

One major problem with having a YB of communications intercepts is that you need to have multiple copies of it for protection in case of human or technical error.

Apparently, NSA has a secondary data center to backup its Utah facility in San Antonio.   That’s one copy.   We also wrote another post on protecting and indexing all this data (see my Protecting the Yottabyte Archive post)

NSA data centers

The Utah facility has enough fuel onsite to power and cool the data center for 3 days.  They have a special power station to supply the 65MW of power needed.   They have two side by side raised floor halls for servers, storage and switches, each with 25K square feet of floor space. That doesn’t include another 900K square feet of technical support and office space to secure and manage the data center.

In order to help collect and temporarily storage all this information, apparently the agency has been undergoing a data center building boom, renovating and expanding their data centers throughout the states.  The article discusses some of other NSA information collection points/data centers, in Texas, Colorado, Georgia, Hawaii, Tennessee, and of course,  Maryland.

New NSA super computers

In addition to the communication intercept storage, the article also talks about a special purpose, decrypting super computer that NSA has invented over the past decade which will also be housed in the Utah data center.  The NSA seems to have created a super powerful computer that dwarfs the current best Cray XT5 super computer clusters that operate at 1.75 petaflops available today.

I suppose what with all the encrypted traffic now being generated, NSA would need some way to decrypt this information in order to understand it.  I was under the impression that they were interested in the non-encrypted communications, but I guess NSA is even more interested in any encrypted traffic.

Decrypting old data

With all this data being stored, the thought is that the data now encrypted with unbreakable AES-128, -192 or -256 encryption will eventually become decypherable.  At that time, foriegn government and other secret communications will all be readable.

By storing this secret communications now, they can scan this treasure trove for patterns that eventually occur and once found, such patterns will ultimately lead to decrypting the data.  Now we know why they need YB of storage.

So NSA will at least know what was going on in the past.  However, how soon they can move that up to do real time decryption of communications today is another question.  But knowing the past, may help in understanding what’s going on today.

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So be careful what you say today even if it’s encrypted.  Someone (NSA and its peers around the world) will probably be listening in and someday soon, will understand every word that’s been said.

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