Random access, DNA object storage system

Read a couple of articles this week Inching closer to a DNA-based file system in ArsTechnica and DNA storage gets random access in IEEE Spectrum. Both of these seem to be citing an article in Nature, Random access in large-scale DNA storage (paywall).

We’ve known for some time now that we can encode data into DNA strings (see my DNA as storage … and Genomic informatics takes off posts).

However, accessing DNA data has been sequential and reading and writing DNA data has been glacial. Researchers have started to attack the sequentiality of DNA data access. The prize, DNA can store 215PB of data in one gram and DNA data can conceivably last millions of years.

Researchers at Microsoft and the University of Washington have come up with a solution to the sequential access limitation. They have used polymerase chain reaction (PCR) primers as a unique identifier for files. They can construct a complementary PCR primer that can be used to extract just DNA segments that match this primer and amplify (replicate) all DNA sequences matching this primer tag that exist in the cell.

DNA data format

The researchers used a Reed-Solomon (R-S) erasure coding mechanism for data protection and encode the DNA data into many DNA strings, each with multiple (metadata) tags on them. One of tags is the PCR primer tag header, another tag indicates the position of the DNA data segment in the file and an end of data tag that is the same PCR primer tag.

The PCR primer tag was used as sort of a file address. They could configure a complementary PCR tag to match the primer tag of the file they wanted to access and then use the PCR process to replicate (amplify) only those DNA segments that matched the searched for primer tag.

Apparently the researchers chunk file data into a block of 150 base pairs. As there are 2 complementary base pairs, I assume one bit to one base pair mapping. As such, 150 base pairs or bits of data per segment means ~18 bytes of data per segment. Presumably this is to allow for more efficient/effective encoding of data into DNA strings.

DNA strings don’t work well with replicated sequences of base pairs, such as all zeros. So the researchers created a random sequence of 150 base pairs and XOR the file DNA data with this random sequence to determine the actual DNA sequence to use to encode the data. Reading the DNA data back they need to XOR the data segment with the random string again to reconstruct the actual file data segment.

Not clear how PCR replicated DNA segments are isolated and where they are originally decoded (with a read head). But presumably once you have thousands to millions of copies of a DNA segment,  it’s pretty straightforward to decode them.

Once decoded and XORed, they use the R-S erasure coding scheme to ensure that the all the DNA data segments represent the actual data that was encoded in them. They can then use the position of the DNA data segment tag to indicate how to put the file data back together again.

What’s missing?

I am assuming the cellular data storage system has multiple distinct cells of data, which are clustered together into some sort of organism.

Each cell in the cellular data storage system would hold unique file data and could be extracted and a file read out individually from the cell and then the cell could be placed back in the organism. Cells of data could be replicated within an organism or to other organisms.

To be a true storage system, I would think we need to add:

  • DNA data parity – inside each DNA data segment, every eighth base pair would be a parity for the eight preceding base pairs, used to indicate when a particular base pair in eight has mutated.
  • DNA data segment (block) and file checksums –  standard data checksums, used to verify and correct for double and triple base pair (bit) corruption in DNA data segments and in the whole file.
  • Cell directory – used to indicate the unique Cell ID of the cell, a file [name] to PCR primer tag mapping table, a version of DNA file metadata tags, a version of the DNA file XOR string, a DNA file data R-S version/level, the DNA file length or number of DNA data segments, the DNA data creation data time stamp, the DNA last access date-time stamp,and DNA data modification data-time stamp (these last two could be omited)
  • Organism directory – used to indicate unique organism ID, organism metadata version number, organism unique cell count,  unique cell ID to file list mapping, cell ID creation data-time stamp and cell ID replication count.

The problem with an organism cell-ID file list is that this could be quite long. It might be better to somehow indicate a range or list of ranges of PCR primer tags that are in the cell-ID. I can see other alternatives using a segmented organism directory or indirect organism cell to file lists b-tree, which could hold file name lists to cell-ID mapping.

It’s unclear whether DNA data storage should support a multi-level hierarchy, like file system  directories structures or a flat hierarchy like object storage data, which just has buckets of objects data. Considering the cellular structure of DNA data it appears to me more like buckets and the glacial access seems to be more useful to archive systems. So I would lean to a flat hierarchy and an object storage structure.

Is DNA data is WORM or modifiable? Given the effort required to encode and create DNA data segment storage, it would seem it’s more WORM like than modifiable storage.

How will the DNA data storage system persist or be kept alive, if that’s the right word for it. There must be some standard internal cell mechanisms to maintain its existence. Perhaps, the researchers have just inserted file data DNA into a standard cell as sort of junk DNA.

If this were the case, you’d almost want to create a separate, data  nucleus inside a cell, that would just hold file data and wouldn’t interfere with normal cellular operations.

But doesn’t the PCR primer tag approach lend itself better to a  key-value store data base?

Photo Credit(s): Cell structure National Cancer Institute

Prentice Hall textbook

Guide to Open VMS file applications

Unix Inodes CSE410 Washington.edu

Key Value Databases, Wikipedia By ClescopOwn work, CC BY-SA 4.0, Link

Blockchains go mainstream…

 

I read an article a while back on Finland’s use of blockchain technology to provide bank accounts and identity services to immigrants (see  MIT TechReview article about Finland).

Blockchains were originally invented as a way of supporting financial transactions outside the current, government monitored, financial marketplace. With Finland’s experiment, the government is starting to use blockchains to support the unbanked and monitoring their financial activity – go figure.

Debit cards on blockchain

Finland’s using a Helsinki based startup MONI, to assign a MONI card, essentially a prepaid MasterCard, to all immigrants. An immigrant can use their MONI card to pay for anything online or in real life, use it as a direct deposit account or to receive and track the use of government assistance.

Underlying the MONI card is public blockchain technology. That is MONI  is not using normal credit card services to support it’s bank accounts, MONI money transfers are done through the use of public blockchains.

MONI accounts are essentially (crypto currency) wallets but used as a debit card. The user merely enters a series of numbers into web forms or uses their MONI card at a credit card terminals throughout Europe. Transferring money between MONI users anywhere in the World is also free and instantaneous.

Finland also sees an immutable record of all immigrant financial transactions,  that can be monitored to track immigrant (financial) integration into the country.

MONI is intending to make this service more broadly available. A MONI card account costs €2/month and MONI take’s a small cut out of each monetary transaction.

IDs on blockchain

I read another article the other day “Microsoft to implement blockchain-based ID system” in CoinTelegraph about using blockchains as a universal digital ID.

India has over the last decade, implemented a digital government ID using biometrics (see Aadhaar wikipedia article). Other countries have been moving to e-government where use of government services is implemented over the Internet (see EU article on eGovernment in Lithuania). Such eGovernment services depend on a digitized population registry.

Although it’s unclear whether Aadhaar and Lithuania make use of blockchain technology for their ID services, Microsoft’s definitely looking to blockchains to provide unique accounts/digital IDs to it’s population of users.

User signon’s has been a prevalent problem of the web for years. Each and every web and mobile App requires a person to signon to personalize their App. Nowadays, many Apps support using Google ID or Facebook ID for a single signon and there are other technologies being offered that provide similar services. Using a blockchain ID could easily support a single signon service.

The blockchain ID (wallet) public key could easily be used to encrypt an authentication transaction, identifying the App and the user. This authentication transaction would be processed by the blockchain digital ID service would use the private key to decrypt the transaction and use a backend ID App repository for the user to check to see that the user loging in, is the person that opened the account, acting as a sort of “proof of who you are”

Storage on blockchain

Filecoin and StorJ are storage providers that use blockchain services to allow others to use your local (or networked) storage to provide storage to the world.

A while back I had written about (free) peer to peer storage and compute services  (see my Free P2P cloud storage … post). But the problem was how do people benefit from hosting the P2P storage or compute. Filecoin and Storj solved this by paying in cryptocurrencies for storage hosted on your hardware.

Filecoin offers a storage auction and hosting service that anyone worldwide can log into and use. The data stored is encrypted end-to-end so that no one can see what’s being stored and the data is also erasure coded so that it  is protected and accessible even with having one or more hosting sites be offline.

Filecoin uses “proofs of storage“, “proofs of space”, “proofs of data possession“, and “proofs of retrievability” as a way to guarantee their storage service works properly. They also use chained “proofs of replication” as “proofs of spacetime” as service validation checks. Proofs of Replication are a way of insuring that storage providers are not deduplicating data copies and charging for non-deduped storage. (See Filecoin’s Proof of Replication paper for more info).

Storj looks somewhat similar to Filecoin, but without as much sophistication behind it.

Compute on blockchain

Ethereum was invented to support smart contracts that run on blockchain technology. IBM’s HyperLegder OpenLedger project (see our GreyBeardsOnStorga Podcast and RayOnStorage post on Hyperledger) is another example.

Smart contracts are essentially applications that run in a blockchains virtualized environment. Blockchain services are used to run an application and validate that’s it’s run only once. In some cases smart contracts use  external oracles to query as a way to verify something or some action has occurred outside the blockchain. Other oracles can be entirely digital entities that check on a particular commodity price, weather pattern, account value, etc. The oracle becomes a critical step in determining the go no go status of a smartcontract.

Advertisements vs. crypto mining

Salon, a news providing website, offers readers an option to see advertisements or to allow Salon to use their computer (browser) to mine crypto coins. (See Salon offers… article in CoinDesk).

I believe this offer is made when the website detects a viewer is using  ad blockers.

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Tthe trend is clear, people, organizations and even governments are looking at blockchain technology to provide basic and advanced services around the world.

If anyone would is interested in providing a pre-paid Visa card via blockchains, please contact me. I’d like to help.

Now if I could just find my GPU’s at a decent price somewhere…

Speaking of advertising… RayOnStorage doesn’t use advertising. But blogging like this takes time and money. If anyone’s interested in helping fund this blog, please consider sending some BTC our way, even 0.0001 BTC would help.

Our BTC wallet address is:

1MqBbAvMo6QbCVD6ZwtbLaPxmcUZGj9Ghw

Photo Credit(s): Blockchain and the public sector on OpenGovAsia.com

Unleash your design teams with single signon on Unifilabs.com

Understanding the difference between P2P and Client-server networks on LinkedIN

Blockgeek’s guide to smart contracts

A knowledge ark, the Arch project

Read an article last week on the Arch Mission Foundation project, which is a non-profit, organization that intends “to continuously preserve and disseminate human knowledge throughout time and space”.

The way I read this is they want to capture, preserve  and replicate all mankind’s knowledge onto (semi-)permanent media and store this information  at various locations around the globe and wherever we may go.

Interesting way to go about doing this. There are plenty of questions and considerations to capturing all of mankind’s knowledge.

Google’s way

 Google has electronically scanned every book in a number of library partners to help provide a searchable database of literature, check out the Google Books Library Project.

There’s over 40 library partners around the globe and the intent of the project was to digitize their collections. The library partners can then provide access to their digital copies. Google will provide full access to books in the public domain and will provide search results for all the rest, with pointers as to where the books can be found in libraries, purchased and otherwise obtained.

Google Books can be searched at Google Books. Last I heard they had digitized over 30M books from their library partners, which is pretty impressive since the Library of Congress has around 37M books. Google Books is starting to scan magazines as well.

Arch’s way

The intent is to create Arch’s (pronounced Ark’s) that can last billions of years. The organization is funding R&D into long lived storage technologies.

Some of these technologies include:

  • 5D laser optical data storage in quartz, I wrote about this before (see my 5D storage … post). Essentially, they are able to record two-tone scans of documents in transparent quartz that can last eons. Data is recorded in 5 dimensions, size of dot, polarity of dot  and 3 layers of dot locations through the media. 5D media lasts for 1000s of years.
  • Nickel ion-beam atomic scale storage, couldn’t find much on this online but we suppose this technology uses ion-beams to etch a nickel surface with nano-scale information.
  • Molecular storage on DNA molecules, I wrote about this before as well (see my DNA as storage… post) but there’s been plenty of research on this more recently. A group from Padua, IT  shows the way forward to use bacteria as a read/write head for DNA storage and there are claims that a gram of DNA could hold a ZB (zettabyte, 10**21 bytes) of data. For some reason Microsoft has been very active in researching this technology and plan to add it to Azure someday.
  • Durable space based flash drives, couldn’t find anything on this technology but assume this is some variant of NAND storage optimized for long duration.  Current NAND loses charge over time. Alternatively, this could be a version of other NVM storage, such as, MRAM, 3DX, ReRAM, Graphene Flash, and  Memristor all of which I have written about
  • Long duration DVD technology, this is sort of old school but there exists archive class WORM DVDs out and available on the market today, (see my post on M[illeniata]-Disc…).
  • Quantum information storage, current quantum memory lifetimes don’t much over exceed 180 seconds, but this is storage not memory. Couldn’t find much else on this, but it might be referring to permanent data storage with light.
M-Disc (c) 2011 Millenniata (from their website)
M-Disc (c) 2011 Millenniata (from their website)

They seem technology agnostic but want something that will last forever.

But what knowledge do they plan to store

In Arch’s FAQ they talk about open data sets like Wikipedia and the Internet Archive. But they have an interesting perspective on which knowledge to save. From an advanced future civilization perspective, they are probably not as interested in our science and technology but rather more interested in our history, art and culture.

They believe that science and technology should be roughly the same in every advanced civilization. But history, art and culture are going to be vastly different across different civilizations. As such, history, art and culture are uniquely valuable to some future version of ourselves or any other advanced scientific civilization.

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Arch intends to have multiple libraries positioned on the Earth, on the Moon and Mars over time. And they are actively looking for donations and participation (see link above).

Although, I agree that culture, art and history will be most beneficial to any advanced civilization. But there’s always a small but distinct probability that we may not continue to exist as an advanced scientific civilization. In that case, I would think, science and technology would also be needed to boot strap civilization.

To the Wikipedia, I would add GitHub, probably Google Books, and PLOS as well as any other publicly available scientific or humanities journals that available.

And don’t get me started on what format to record the data with. Needless to say, out-dated formats are going to be a major concern for anything but a 2D scan of information after about ten years or so.

In any case, humanity and universanity needs something like this.

Photo Credit(s): The Arch Mission Foundation web page

Google Books Library search on Republic results

“Five dimensional glass disks …” from The Verge

M-disk web page

Atomristors, a new single (atomic) layer memristor

Read an article the other day about the “Atomristor: non-volatile resistance  switching in atomic sheets of transition metal dichalcogenides” (TMDs), an ACS publication. The article shows research that discovered an atomic sheet level version of a memristor. The device is an atomic sheet of TMD that is sandwiched between two (gold, silver or graphene) electrodes.

They refer to the device switching non-volatile resistance (NVR) from low to high or vice versa but from our perspective it could just as easily be considered a non-volatile device usable for memory, storage, or electronic circuitry.

Prior to this research, it was believed that such resistance switching could not be accomplished with single atomic, sub-nanometre (0.7nm) sized, sheet of material.

NVR atomristor technological properties

The researchers discovered that NVR switching can occur at different device temperatures, sheet areas, compliance current, voltage sweep rate, and layer thickness. In all five degrees of freedom were tested to show that  TMD atomristors had wide applicability and allowed for significant environmental and electronic variability.

Not only was the effect extremely versatile, the researchers identified multiple materials which could be used for the atomic sheet. In fact, TMD are a class of materials and they showed 4 different TMD materials that had the NVR effect.

Surprisingly, some TMD materials exhibited the NVR effect using unipolar voltages and some using bipolar voltages, and some could use both.

The researchers went a long way to showing that the NVR was due to the atomic sheet. In one instance they specifically used non-lithographic measures to fabricate the devices. This process utilized graphene manufacturing like methods to produce an atomic sheet ontop of gold foil and depositing another gold layer ontop of that.

But they also used standard fabrication techniques to build the atomristor devices as well. Using these different fabrication methods, they were able to show the NVR effect using different electrodes types, testing gold, silver, and graphene, all of which worked similarly.

The paper talked of using atomristors in a software defined radio, as a electronic circuit/cross bar switch, or as a memory/storage device. But they also indicated that it could easily be used in a neuromorphic computer as well, effectively simulating neuron like computations.

There’s much more information in the ACS article.

How does it compare to flash?

As compared to flash, atomristors NVR devices should be able to provide higher levels (bits per mm) of density. And due to the lower current (~1v) required for (bipolar) NVR setting, reading and resetting, there’s a lower probability of leakage of stored charges as they’re scaled down to nm sizes.

And of course it comes in 2d sheets, so it’s just as amenable to 3D arrays as NAND and 3DX is today. That means that as fabs start scaling 3D NAND up in layers, atomristor NVR devices should be able to follow their technology roadmap to be scaled up just as high.

Atomristor computers, storage or switch devices

Going from the “lab” to an IT shop is a multifaceted endeavour that takes a lot of time. There are many steps to needed to get to commercialization and many lab breakthroughs never make it that far because of complexity, economics, and other factors.

For instance, memristors were first proposed in 1971 and HP(E) researchers first discovered material that could produce the memristor effect in 2008. In March 2012, HRL fabricated the first memristor chip on CMOS. In Dec. 2017, >9 years later, at their Discover Conference, HPE showed off “The Machine”, a prototype of a memristor based computer to the public. But we are still waiting to see one on the market for sale.

That being said, memristor technologies didn’t exist before 2008, so the use of these devices in a computer took sometime to be understood. The fact that atomristors are “just” an extremely, thinner version of memristors should help it be get to market faster that original memristor technologies. But how much faster than 9-12 years is anyone’s guess.

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Comments?

Picture Credit(s): All graphics and pictures are from the article in ACS

Scratch file use in HPC @ORNL, a statistical analysis

Attended SC17 (Supercomputing Conference) this past week and I received a copy of the accompanying research proceedings. There are a number of interesting papers in the research and I came across one, Scientific User Behavior and Data Sharing Trends in a Peta Scale File System by Seung-Hwan Lim, et al from Oak Ridge National Laboratory (ORNL) and the use of files at the Oak Ridge Leadership Computing Facility (OLCF) which was very interesting.

The paper statistically describes the use of a Scratch files in a multi PB file system (Lustre) at OLCF from January 2015 to August 2016. The OLCF supports over 32PB of storage, has a peak aggregate of over 1TB/s and Spider II (current Lustre file system) consists of 288 Lustre Object Storage Servers, all interconnected and connected to all the supercomputing cluster of  servers via an InfiniBand network. Spider II supports all scratch storage requirements for active/queued jobs for the Titan (#4 in Top 500 [super computer clusters worldwide] list) and other clusters at ORNL.

ORNL uses an HPSS (High Performance Storage System) archive for permanent storage but uses the Spider II file system for all scratch files generated and used during supercomputing applications.  ORNL is expecting Spider III (2018-2023) to host 10 billion files.

Scratch files are purged from Spider II after 90 days of no access.The paper is based on metadata analysis captured during scratch purging process for 500 days of access.

The paper displays a number of statistics and metrics on the use of Spider II:

  • Less than 3% of projects have a directory depth >15, the maximum directory depth was recorded at 432, with most projects having a shallow (<10) directory depth.
  • A project typically has 10X the files that a specific researcher has and a median file count/researcher is 2000 files with a median project having 20,000 files.
  • Storage system performance is actively managed by many projects. For instance, 20 out of 35 science domains manually managed their Lustre cluster configuration to improve throughput.
  • File count continues to grow and reached a peak of 1B files during the time being analyzed.
  • On average only 3% of files were accessed readonly, 10% of files updated (read-write) and 76% of files were untouched during a week period. However, median and maximum file age was 138 and 214 days respectively, which means that these scratch files can continue to be accessed over the course of 200+ days.

There was more information in the paper but one item missing is statistics on scratch file size distribution a concern.

Nonetheless, in paints an interesting picture of scratch file use in HPC application/supercluster environments today.

Comments?

Disk rulz, at least for now

Last week WDC announced their next generation technology for hard drives, MAMR or Microwave Assisted Magnetic Recording. This is in contrast to HAMR, Heat (laser) Assisted Magnetic Recording. Both techniques add energy so that data can be written as smaller bits on a track.

Disk density drivers

Current hard drive technology uses PMR or Perpendicular Magnetic Recording with or without SMR (Shingled Magnetic Recording) and TDMR (Two Dimensional Magnetic Recording), both of which we have discussed before in prior posts.

The problem with PMR-SMR-TDMR is that the max achievable disk density is starting to flat line and approaching the “WriteAbility limit” of the head-media combination.

That is even with TDMR, SMR and PMR heads, the highest density that can be achieved is ~1.1Tb/sq.in. The Writeability limit for the current PMR head-media technology is ~1.4Tb/sq.in. As a result most disk density increases over the past years has been accomplished by adding platters-heads to hard drives.

MAMR and HAMR both seem able to get disk drives to >4.0Tb/sq.in. densities by adding energy to the magnetic recording process, which allows the drive to record more data in the same (grain) area.

There are two factors which drive disk drive density (Tb/sq.in.): Bits per inch (BPI) and Tracks per inch (TPI). Both SMR and TDMR were techniques to add more TPI.

I believe MAMR and HAMR increase BPI beyond whats available today by writing data on smaller magnetic grain sizes (pitch in chart) and thus more bits in the same area. At 7nm grain sizes or below PMR becomes unstable, but HAMR and MAMR can record on grain sizes of 4.5nm which would equate to >4.5Tb/sq.in.

HAMR hurdles

It turns out that HAMR as it uses heat to add energy, heats the media drives to much higher temperatures than what’s normal for a disk drive, something like 400C-700C.  Normal operating temperatures for disk drives is  ~50C.  HAMR heat levels will play havoc with drive reliability. The view from WDC is that HAMR has 100X worse reliability than MAMR.

In order to generate that much heat, HAMR needs a laser to expose the area to be written. Of course the laser has to be in the head to be effective. Having to add a laser and optics will increase the cost of the head, increase the steps to manufacture the head, and require new suppliers/sourcing organizations to supply the componentry.

HAMR also requires a different media substrate. Unclear why, but HAMR seems to require a glass substrate, the magnetic media (many layers) is  deposited ontop of the glass substrate. This requires a new media manufacturing line, probably new suppliers and getting glass to disk drive (flatness-bumpiness, rotational integrity, vibrational integrity) specifications will take time.

Probably more than a half dozen more issues with having laser light inside a hard disk drive but suffice it to say that HAMR was going to be a very difficult transition to perform right and continue to provide today’s drive reliability levels.

MAMR merits

MAMR uses microwaves to add energy to the spot being recorded. The microwaves are generated by a Spin Torque Oscilator, (STO), which is a solid state device, compatible with CMOS fabrication techniques. This means that the MAMR head assembly (PMR & STO) can be fabricated on current head lines and within current head mechanisms.

MAMR doesn’t add heat to the recording area, it uses microwaves to add energy. As such, there’s no temperature change in MAMR recording which means the reliability of MAMR disk drives should be about the same as todays disk drives.

MAMR uses todays aluminum substrates. So, current media manufacturing lines and suppliers can be used and media specifications shouldn’t have to change much (?) to support MAMR.

MAMR has just about the same max recording density as HAMR, so there’s no other benefit to going to HAMR, if MAMR works as expected.

WDC’s technology timeline

WDC says they will have sample MAMR drives out next year and production drives out in 2019. They also predict an enterprise 40TB MAMR drive by 2025. They have high confidence in this schedule because MAMR’s compatabilitiy with  current drive media and head manufacturing processes.

WDC discussed their IP position on HAMR and MAMR. They have 400+ issued HAMR patents with another 100+ pending and 75 issued MAMR patents with 46 more pending. Quantity doesn’t necessarily equate to quality, but their current IP position on both MAMR and HAMR looks solid.

WDC believes that by 2020, ~90% of enterprise data will be stored on hard drives. However, this is predicated on achieving a continuing, 10X cost differential between disk drives and (QLC 3D) flash.

What comes after MAMR is subject of much speculation. I’ve written on one alternative which uses liquid Nitrogen temperatures with molecular magnets, I called CAMR (cold assisted magnetic recording) but it’s way to early to tell.

And we have yet to hear from the other big disk drive leader, Seagate. It will be interesting to hear whether they follow WDC’s lead to MAMR, stick with HAMR, or go off in a different direction.

Comments?

 

Photo Credit(s): WDC presentation

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


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

 

New chip architecture with CPU, storage & sensors in one package

Read an article the other day in MIT news, (3D chip combines computing and data storage) about a new 3D chip out of Stanford and MIT research, which includes CPU, RRAM (resistive RAM) storage class memories and sensors in one single package. Such a chip architecture vastly minimizes the off chip bottleneck to access storage and sensors.

Chip componentry

The chip’s sensors are based on carbon nanotubes. Aside from a layer of silicon at the bottom, all the rest of transistors used in the chip are also based off of carbon nanotube FET (field effect transistors).

The RRAM storage class memory is a based on a dielectric material which uses electrical resistance to store non-volatile data.

The bottom layer is a silicon based CPU. On top of the silicon is a carbon nanotube layer. Next comes the RRAM and the top layer is more carbon nanotubes making up the sensor array.

Architectural benefits

One obvious benefit is having data storage directly accessible to the CPU is that there’s no longer a need to go off chip to access data. The 2nd major advantage to the chip architecture is that the sensor array can write directly to RRAM storage, so there’s no off chip delay to provide sensor readout and storage.

Another advantage to using carbon nanotube FET’s is that they can be an order of magnitude more energy efficient than silicon transistors. Moreover, RRAM has the potential to be much denser than DRAM.

Finally, another major advantage is that this can all be built in one 3D chip because carbon nanotube and RRAM fabrication can be done at relatively cooler temperatures (~200C) vs. silicon fabrication which requires relatively high temperatures (1000C). Silicon cannot be readily fabricated in multiple layers because of the high temperatures required which will harm lower layers. But you could fabricate the lowest layer in silicon and then the rest as either carbon nanotube FETs or RRAM without harming the silicon layer.

Transistor/RRAM counts

The chip as fabricated has a million RRAM cells (bits?) and 2 million nanotube FETs. In contrast, in 2014, Intel’s 15-core Xeon Ivy Bridge EX had 4.3B transistors and current DRAM chips offer 64Gb. So there’s a ways to go before carbon nanotube and RRAM densities can get to a level available from silicon today.

However, as they have a bottom layer of silicon they can have all the CPU complexity of an Intel processor and still build RRAM and carbon nanotubes FETs on top of that. Which makes this chip architecture compatible with current CMOS fabrication techniques and a very interesting addition to current CPU architectures.

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Unclear to me why they stopped at 4 layers (1-silicon FET, 1 carbon nanotubes FET, 1 RRAM and 1 carbon nanotubes FET [sensor array]). If they can do 4 why not do 5 or more. That way they could pack in even more RRAM storage and perhaps more sensor layers.

Also, not sure what the bottom most layer of carbon nanotubes is doing. If I had to hazard a guess, it’s being used for RRAM control logic. But I could be wrong.

I could see how these chips could be used for very specialized sensor applications, with a limited need for data storage. The researchers claim many types of sensors can be created using carbon nanotubes. If that’s the case, maybe we might see these sorts of chips showing up all over the place.

Comments?

Photo Credit(s): Three dimensional integration of nanotechnologies for computing and data storage on a single chip, Nature magazine.