6 ms·

Short explainer: This is almost the same structure as traditional flash. That is, it has a “floating gate” which sits between the control gate and the channel

by jl2718 5y ago

Short explainer: This is almost the same structure as traditional flash. That is, it has a “floating gate” which sits between the control gate and the channel between source and drain. When a large “write” voltage is applied to the control gate, charge tunnels into the floating gate, and stays there. Then a smaller “read” voltage on the control gate causes conduction in the channel. The main difference here is that the floating gate is made of many thin layers of heterogeneous (III-V) highly-valent semiconductor so that a smaller voltage is needed to tunnel charge into it. Other than the floating gate, this is a very traditional SLC flash structure, and it’s done in a very large area. They use the word “quantum” a lot, but you can substitute that word with “very thin”. I believe the utility of that structure versus bulk III-V is that it creates multiple barriers that allow precise linear control of the tunneling depth over a larger voltage range, and many places for charge to get ‘stuck’, versus one potential well that would just tunnel straight to the drain.

Melatonic 5y ago
So basically this is the opposite of a RAM disk - very interesting. I wonder if the NVME interface is fast enough to support something like this?
- beebeepka 5y ago
  We're getting there https://www.anandtech.com/show/17203/pcie-60-specification-finalized-x16-slots-to-reach-128gbps https://www.anandtech.com/show/17203/pcie-60-specification-f...
- mikepurvis 5y ago
  NVMe is just a 4-lane PCIe interface with a different connector. So if that's not fast enough, it could instead go on a 8x or 16x expansion card. The question for me would be whether this is truly a drop-in replacement for either disk or RAM, or if it's something that needs to be treated as a separate peripheral while new applications are written to really take advantage of it— for example, a database that DMAs directly from permanent storage to the network with no concept of loading or caching anything in RAM.
  - naikrovek 5y ago
    > The question for me would be whether this is truly a drop-in replacement for either disk or RAM a single device would not be a drop-in replacement of both RAM and SSD for today's computers. fundamental assumptions are made at the architecture level of today's computers which preclude RAM and bulk storage being anything but separate. a replacement for one or another could be possible for today's machines, though. or both, if you have two devices with the correct connectors. but not both if they share address space. what does it mean for an operating system, or even an application, to "start up" when all that really means is moving data to RAM so it can be accessed quickly enough? when storage and RAM do finally converge, there will be no "boot" process in the conventional sense. you will power the device up and it will be ready instantly; everything is already "in RAM" the instant power is applied.
    - staticassertion 5y ago
      Well, more than that happens when a program starts up. It's mapped in, libraries will be dynamically linked in, an address space has to be allocated, a process structure has to be allocated, memory has to be mapped as executable, etc. I don't think we would want "program on hard drive" and "program in memory" to be isomorphic for a bunch of reasons, one being security.
      - naikrovek 5y ago
        There are mitigations for the security concerns; the new architecture I envision is a new architecture, we can do things correctly and intelligently. don't let your x86 experience cloud your view of what can be done. just like an MMU can restrict what process(es) can access a particular byte or block of RAM, something similar could restrict access to a common storage medium. > Well, more than that happens when a program starts up. of course more than that happens. I am trying to make a point and not document the minutia of the entire boot process of a modern x86_64 computer. > I don't think we would want "program on hard drive" and "program in memory" to be isomorphic that is one of the biggest potential reasons to use the technology in question, and one of the biggest reasons that it is being worked on.
- Zenst 5y ago
  Why only the other day https://news.ycombinator.com/item?id=29897713 https://news.ycombinator.com/item?id=29897713 we was pondering what would need all that data bandwidth for the new PCIe-6 specs. Having too much bandwidth or capacity is a problem in IT that often solves itself more often than not.
  - Melatonic 5y ago
    The real problem though is latency - RAM is extremely low latency and that is one of its primary benefits. I can't say for sure what this new tech has but reading about Intel Optane (which is already much lower latency than normal SSD) it seems to have a latency of approximately 1-10us. DDR4 is something like 50ns. Pretty large disparity (my numbers could be off - this was just after some quick searches)
    - Der_Einzige 5y ago
      Check out "Intel Optane DC". You might like what you find, but to my knowledge it's only targeted at data centers.
- formerly_proven 5y ago
  M.2 actually reserved a key for the "Future Memory Interface". That of course must be serdes based due to the pin-count and general physics.
Someone 5y ago
> This is almost the same structure as traditional flash Thus that mean it also is almost as easy to manufacture?
- jl2718 5y ago
  Actually I don’t think this will be very difficult in terms of adding the molecular beam epitaxy steps to the traveler. However, there is massive fab-wide risk from introducing III-V elements into the process, which can contaminate everything, so they may have to build an entirely new fab for this process. It’s been a while for me, so my understanding may be dated.
37 5y ago
>They use the word “quantum” a lot, but you can substitute that word with “very thin”. Holy crow, I hate this.
- staticassertion 5y ago
  The use of quantum seems appropriate as it's referring to quantum tunneling, which is something that comes up a lot with CPU architectures as they get extra tiny.
  - judge2020 5y ago
    I believe this is what you're referring to https://en.wikipedia.org/wiki/QFET https://en.wikipedia.org/wiki/QFET
SavantIdiot 5y ago
The key here is that it is RAM-like WRITE speed. We've had RAM-like read speed for over 20 years.
- hypertele-Xii 5y ago
  Seems suspect. What hard drive has had RAM-like read speed for over 20 years?
  - mhio 5y ago
    I'm guessing the page cache for hot data?
    - hypertele-Xii 5y ago
      Is that non-volatile? (retains its memory without power)
  - SavantIdiot 5y ago
    Let's go back to 2002, toshiba announces 1GB compact flash memory card with a read speed of 6.5MB/second (maximum). Compare that to 2002 Hynix Net DDR II with a read speed of about 100MB/s and clearly you can see how wrong I am. My bad, I was confusing Flash that had a DRAM-like interface, and Flash that could read as fast as DRAM. But I cannot edit my response now.
  - Maursault 5y ago
    What is "RAM-like speed?" It certainly was a different value 20 years ago than it is today. I'm restoring a machine from 1989 that on a good day can push 15MB/s through RAM, while I think contemporary RAM will do more than 12GB/s. GP's statement is ambiguous. RAM has always been perceived as fast, but storage was always perceived as slow, for decades, and didn't begin to get fast until 20 years ago. I think if there were 15MB/s HDDs matching RAM bandwidth in 1989 it would seem a lot more impressive than a really really fast, near-RAM bandwidth-fast SSD today, even though 12GB/s is so crazy fast it is beyond comprehension.

by jl2718 5y ago

Melatonic 5y ago

So basically this is the opposite of a RAM disk - very interesting. I wonder if the NVME interface is fast enough to support something like this?

beebeepka 5y ago
We're getting there https://www.anandtech.com/show/17203/pcie-60-specification-finalized-x16-slots-to-reach-128gbps https://www.anandtech.com/show/17203/pcie-60-specification-f...
mikepurvis 5y ago
NVMe is just a 4-lane PCIe interface with a different connector. So if that's not fast enough, it could instead go on a 8x or 16x expansion card. The question for me would be whether this is truly a drop-in replacement for either disk or RAM, or if it's something that needs to be treated as a separate peripheral while new applications are written to really take advantage of it— for example, a database that DMAs directly from permanent storage to the network with no concept of loading or caching anything in RAM.
- naikrovek 5y ago
  > The question for me would be whether this is truly a drop-in replacement for either disk or RAM a single device would not be a drop-in replacement of both RAM and SSD for today's computers. fundamental assumptions are made at the architecture level of today's computers which preclude RAM and bulk storage being anything but separate. a replacement for one or another could be possible for today's machines, though. or both, if you have two devices with the correct connectors. but not both if they share address space. what does it mean for an operating system, or even an application, to "start up" when all that really means is moving data to RAM so it can be accessed quickly enough? when storage and RAM do finally converge, there will be no "boot" process in the conventional sense. you will power the device up and it will be ready instantly; everything is already "in RAM" the instant power is applied.
  - staticassertion 5y ago
    Well, more than that happens when a program starts up. It's mapped in, libraries will be dynamically linked in, an address space has to be allocated, a process structure has to be allocated, memory has to be mapped as executable, etc. I don't think we would want "program on hard drive" and "program in memory" to be isomorphic for a bunch of reasons, one being security.
    - naikrovek 5y ago
      There are mitigations for the security concerns; the new architecture I envision is a new architecture, we can do things correctly and intelligently. don't let your x86 experience cloud your view of what can be done. just like an MMU can restrict what process(es) can access a particular byte or block of RAM, something similar could restrict access to a common storage medium. > Well, more than that happens when a program starts up. of course more than that happens. I am trying to make a point and not document the minutia of the entire boot process of a modern x86_64 computer. > I don't think we would want "program on hard drive" and "program in memory" to be isomorphic that is one of the biggest potential reasons to use the technology in question, and one of the biggest reasons that it is being worked on.
Zenst 5y ago
Why only the other day https://news.ycombinator.com/item?id=29897713 https://news.ycombinator.com/item?id=29897713 we was pondering what would need all that data bandwidth for the new PCIe-6 specs. Having too much bandwidth or capacity is a problem in IT that often solves itself more often than not.
- Melatonic 5y ago
  The real problem though is latency - RAM is extremely low latency and that is one of its primary benefits. I can't say for sure what this new tech has but reading about Intel Optane (which is already much lower latency than normal SSD) it seems to have a latency of approximately 1-10us. DDR4 is something like 50ns. Pretty large disparity (my numbers could be off - this was just after some quick searches)
  - Der_Einzige 5y ago
    Check out "Intel Optane DC". You might like what you find, but to my knowledge it's only targeted at data centers.
formerly_proven 5y ago
M.2 actually reserved a key for the "Future Memory Interface". That of course must be serdes based due to the pin-count and general physics.

Someone 5y ago

> This is almost the same structure as traditional flash Thus that mean it also is almost as easy to manufacture?

jl2718 5y ago
Actually I don’t think this will be very difficult in terms of adding the molecular beam epitaxy steps to the traveler. However, there is massive fab-wide risk from introducing III-V elements into the process, which can contaminate everything, so they may have to build an entirely new fab for this process. It’s been a while for me, so my understanding may be dated.

37 5y ago

>They use the word “quantum” a lot, but you can substitute that word with “very thin”. Holy crow, I hate this.

staticassertion 5y ago
The use of quantum seems appropriate as it's referring to quantum tunneling, which is something that comes up a lot with CPU architectures as they get extra tiny.
- judge2020 5y ago
  I believe this is what you're referring to https://en.wikipedia.org/wiki/QFET https://en.wikipedia.org/wiki/QFET

SavantIdiot 5y ago

The key here is that it is RAM-like WRITE speed. We've had RAM-like read speed for over 20 years.

hypertele-Xii 5y ago
Seems suspect. What hard drive has had RAM-like read speed for over 20 years?
- mhio 5y ago
  I'm guessing the page cache for hot data?
  - hypertele-Xii 5y ago
    Is that non-volatile? (retains its memory without power)
- SavantIdiot 5y ago
  Let's go back to 2002, toshiba announces 1GB compact flash memory card with a read speed of 6.5MB/second (maximum). Compare that to 2002 Hynix Net DDR II with a read speed of about 100MB/s and clearly you can see how wrong I am. My bad, I was confusing Flash that had a DRAM-like interface, and Flash that could read as fast as DRAM. But I cannot edit my response now.
- Maursault 5y ago
  What is "RAM-like speed?" It certainly was a different value 20 years ago than it is today. I'm restoring a machine from 1989 that on a good day can push 15MB/s through RAM, while I think contemporary RAM will do more than 12GB/s. GP's statement is ambiguous. RAM has always been perceived as fast, but storage was always perceived as slow, for decades, and didn't begin to get fast until 20 years ago. I think if there were 15MB/s HDDs matching RAM bandwidth in 1989 it would seem a lot more impressive than a really really fast, near-RAM bandwidth-fast SSD today, even though 12GB/s is so crazy fast it is beyond comprehension.