[HN Gopher] Computer memory prototype ditches 1s and 0s for dens...
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Computer memory prototype ditches 1s and 0s for denser data storage
Author : DamnInteresting
Score : 14 points
Date : 2023-07-17 20:41 UTC (2 hours ago)
(HTM) web link (newatlas.com)
(TXT) w3m dump (newatlas.com)
| failuser wrote:
| Vinyl records also don't have 0's and zeroes, it does not make
| them better than Blu-ray. MLC NAND have more than just 1's and
| 0's, they have 0..7 or even 0..15. Does anyone really want to
| process analog data?
| mcdonje wrote:
| 1. Vinyl ridges are much larger than DVD lines. Kind of a silly
| comparison considering the article claims the density of this
| scheme would exceed what we currently have.
|
| 2. It appears to not be analog.
|
| >An energy barrier is created at the points where the bridges
| meet the device contacts, and the height of this barrier can be
| controlled which changes the electrical resistance of the
| overall material. That in turn is what encodes the data.
|
| That seems to indicate they can have a base-n encoding where n
| is what they can practically achieve with the barrier/bridge
| layering scheme.
| failuser wrote:
| They claim it's continuous. If continuous values itself were
| that great then the vinyl records were great for data
| storage. The problem with continuous values is noise,
| durability and precision. You can made vinyl disks with
| incredibly high precision, but preventing damage and reading
| back those values is not practical. That's why even the first
| analog laser medium had discrete pits and lands instead of a
| continuous signal.
| AnotherGoodName wrote:
| It can be continuous but still have a limit to data due to
| noise. In vinyls case the more data you store the higher
| the error rate (at some point the differences in states is
| hidden in noise).
|
| The data rate from a noisy channel or storage can be
| derived from Shannon-hartley theorem.
|
| This is why the old analogue phones could only do 56k for
| example.
| failuser wrote:
| Yes, that's why I hate their headline.
| karmakaze wrote:
| Something that's continuous is analog. I would even say that
| the MLC/TLC/QLC use analog storage to represent multiple bits
| per site.
|
| We would already have something similar with SSD and many
| more bits/levels per site if voltages were precise and stable
| over time and number of overwrites.
|
| An interesting use would be for storing 1-dimensional data.
| In effect the errors would be minor and not
| randomized/scattered as it would be for digital encodings.
| eyegor wrote:
| Wasn't optane a pretty noticeable leap in voltage
| stability? They could've eventually pivoted to high density
| packing if they hadn't given up.
| PhasmaFelis wrote:
| > Does anyone really want to process analog data?
|
| If they can get it to encode binary data more densely than
| existing systems, with acceptable speed/reliability/cost? Yes,
| of course they would.
| vlovich123 wrote:
| > Does anyone really want to process analog data?
|
| I imagine at some point in the abstractions it'll get a compat
| layer. Also, I could be wrong about MLC NAND but I thought it
| still stored 0/1 and just had more bits stored per cell through
| stacking.
| whatevaa wrote:
| No, multi-level NAND has extra voltage levels. Instead of a
| just regular off (0) and on (1) they have intermediate states
| too. For QLC, that's 16 levels, it's quite granular, and the
| margins of error are very small.
| Retr0id wrote:
| The margins for error are wider than one might immediately
| assume, since they combine it with error correction codes.
| sp332 wrote:
| TLC NAND stores one of eight values in the cell. There aren't
| three separate values like 1, 0, 1, there is only one value,
| like "5".
| AussieWog93 wrote:
| I mean, 101 is just 5 in binary.
|
| So each cell stores either three pieces of binary or one
| piece of octal. It's the same thing.
| chimeracoder wrote:
| Binary data simply means that each datum encodes exactly one of
| two states. We represent them as 0s and 1s, but that's just an
| abstraction of convenience - physically, that maps to something
| like "high voltage" and "low voltage", or "dark" and "light", or
| "on" and "off", depending on the physical medium.
|
| We could have three states - "high voltage", "medium voltage" and
| "low voltage" - but the advantage of having exactly two is that
| it makes it harder to mistake one state for another (e.g. if
| voltage fluctuates within a specific range). If the measurement
| range for each datum is (0, 100), you can decide that anything
| below 50 is "low voltage" and anything below 100 is "high
| voltage". You can also do the same thing with (0,33), <33,66),
| <66,100), but that requires assuming more precise tools
| throughout the entire pipeline. When we talk about bits getting
| flipped (the entire reason that checksums exist in wire
| protocols), that's the reason: the medium conducting the signal
| is imprecise, and sometimes the reading is off.
|
| Traditionally, this represents a tradeoff between density and
| fidelity. If your system has high enough fidelity, you can take
| advantage of the additional precision and distinguish between
| more states, representing additional information.
|
| If your system has 8 states (0,8.3), <8.3, 16.6)... etc., you can
| look at this as an octal system, or you can think of it as a
| binary system in which a read/write error affects an entire byte,
| rather than a single bit.
|
| At the end of the day, this is a question of signal processing -
| binary representation is a convenient abstraction that allows us
| to understand the way that we're interpreting the signals we're
| reading, but it's fundamentally an arbitrary choice.
| quasse wrote:
| This is multi-level cell flash memory, and it's been in use for
| years. Instead of "high" or "low" voltage they use the in-
| between states to encode more bits per cell. [1]
|
| I worked at an embedded startup when SD cards started switching
| to MLC and we saw a really notable decrease in storage
| reliability. We ended up sourcing special SD cards that were
| flashed with embedded controller firmware restoring them to
| single level cell functionality. Your storage space is divided
| by 2^n going from n levels of voltage per cell back to SLC, but
| we saw greatly increased data integrity.
|
| [1] https://en.wikipedia.org/wiki/Multi-level_cell
| chimeracoder wrote:
| > This is multi-level cell flash memory, and it's been in use
| for years. Instead of "high" or "low" voltage they use the
| in-between states to encode more bits per cell. [1]
|
| Yes, I'm explaining it with high and low voltage because
| that's an easy example to wrap your head around if you
| haven't thought about signal processing or hardware
| engineering before.
| dmvdoug wrote:
| How much calculus would it require in order to get a decent
| grasp on signal processing? Not to work in the field or
| become an expert, but to gain an at least somewhat
| intelligent outsider's understanding of it?
| rcarr wrote:
| Don't work in the field but I believe fast fourier
| transforms are commonplace so at least enough to have a
| solid grasp of that?
| AYoung010 wrote:
| Most intro classes require calculus 1 & 2.
| tiberius_p wrote:
| Learn what's the deal with the Fourier Transform and the
| Z transform. Then learn how to design some digital FIR
| filters. Oh and do learn about the Nyquist-Shannon
| sampling theorem, it's very important. And that's about
| it...just joking, there's tons more. But that would be a
| good start.
| bonzini wrote:
| Those are known as pseudo-SLC, they are common in industrial
| applications.
| mr_toad wrote:
| > fundamentally an arbitrary choice
|
| It's not arbitrary, it's an engineering choice. It's just
| easier to design binary circuits.
| 1024core wrote:
| How long have we been talking about "new" types of
| memory/storage? Anyone remember memristors?
| hanniabu wrote:
| Has anything happened with memristors?
| p1esk wrote:
| With the recent successes quantizing LLMs to 4 bits,
| memristors can actually be useful. Basically the lower the
| precision the more attractive analog computation becomes.
| renegade-otter wrote:
| The article literally links to another one that talks about the
| "emerging type of memory" - from 2012.
| dale_glass wrote:
| The problem is that any new technology has to compete with half
| a century of improvement made to the current one.
|
| It's not enough to make a proof of concept of your MRAM, FRAM,
| or whatnot. If you want it to catch on you have to also come up
| with a way to quickly start making say, 16GB modules
| competitive with modern DDR5.
|
| That's tough.
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