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Hardware Technology

SD Association Unveils microSD Express Format That Promises Transfer Speeds of Up To 985 MB/s (engadget.com) 72

The SD Association has unveiled microSD Express, a new format that will bring speeds of up to 985 MB/s to the tiny memory cards used in smartphones and other devices. From a report: Like SD Express, it exploits the NVMe 1.3 and PCIe 3.1 interfaces used in PCs to power high-speed SSDs. The tech is incorporated onto the second row of microSD pins, so the cards will work faster in next-gen devices while maintaining backward compatibility with current microSD tech. PCIe 3.1 allows for low power sub-states, so the cards will not only offer much (much) higher transfer speeds, but consume less power than regular microSD cards. It'll also open up features like bus mastering, which lets memory cards communicate with other components without going through the CPU first.
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SD Association Unveils microSD Express Format That Promises Transfer Speeds of Up To 985 MB/s

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  • Countdown to... (Score:5, Insightful)

    by WoodstockJeff ( 568111 ) on Monday February 25, 2019 @01:00PM (#58176860) Homepage

    ... bus mastering being used in an Intel processor exploit in 10, 9, 8 ...

    • Re:Countdown to... (Score:5, Insightful)

      by DarkOx ( 621550 ) on Monday February 25, 2019 @01:21PM (#58177060) Journal

      This was my first thought as well. It seems to me extending to the PCIe bus to all kinds of untrusted hot plugged devices has bad idea written all over it. USB 2.x we "permissive" enough in terms of memory access.

      • by gweihir ( 88907 )

        Well, those that prefer speed over security will at least not have security. The funny thing is that these morons are the ones to complain loudest when they get hit because of their own stupidity...

      • Re:Countdown to... (Score:4, Interesting)

        by tlhIngan ( 30335 ) <slashdot.worf@net> on Monday February 25, 2019 @02:45PM (#58177724)

        This was my first thought as well. It seems to me extending to the PCIe bus to all kinds of untrusted hot plugged devices has bad idea written all over it.

        We already did, twice. First was ExpressCard, which is a card version of a x1 PCIe slot. Second time was Thunderbolt, which I believe the current iteration is up to x4 PCIe.

        And yes, I believe there are Thunderbolt RAM attacks though because of the IO controller, it's somewhat mitigated.

      • I am personally OK with the tradeoff of much better local performance, for an increased security risk around physical presence.

        After all, a hardware maker can do things to make sure ports are disconnected when systems are locked, or in the most drastic cases you can physically render external ports inoperable.

        • One, if the hardware maker is not the OS maker, they can only provide hooks and leave it up to the OS. Two, I don't want all my storage unmounting every time I walk away from my desk.

          • One, if the hardware maker is not the OS maker, they can only provide hooks and leave it up to the OS.

            For desktops that is probably true, although they could have a "lock system" button... you could put it right next to the "Turbo" button some systems used to offer. :-).

            For laptops though, the hardware maker could easily have some kind of physical interlock that disabled anything but power (or even that) to outside ports until the case was opened. The problem there of course, is people that want to run la

          • if there's already a storage device mounted, there's very little reason to unmount if the system is locked. It's already been mounted and had a chance to do it's bad deeds if it's bad.

            He's talking about the idea of not enumerating newly plugged devices if the system is locked, which is 100% in the OS ballpark. I don't want the hardware maker involved in that decision at all, or else the hardware starts doing shit the OS doesn't know about, and a patch to the OS can't fix. That's where bad security proble

      • It seems to me extending to the PCIe bus to all kinds of untrusted hot plugged devices has bad idea written all over it.

        Do you bolt your TV down to your house, or do you lock the front door? I agree that there are security implications with exposing a bus like this, but none that can't be managed externally.

        But in reality how is this any worse at all than Thunderbolt or ExpressCard?

    • ... bus mastering being used in an Intel processor exploit in 10, 9, 8 ...

      If you buy a modern system without a IOMMU, you deserve exactly what you get. We figured out that this was a problem back in the firewire days, and first servers and then desktops sprouted IOMMUs to solve it.

    • Don't worry Intel is immune. They don't provide enough PCIe lanes to attach useful peripherals.

    • For this reason, Windows now has IOMMU virtualization enabled to prevent DMA attacks (starting with Windows 10 RS4/1803/April 2018 Update): https://twitter.com/AmarSaar/status/985618204184768513 [twitter.com]

      In conjunction, tianocore also has IOMMU based DMA protection for 2 years now: https://github.com/tianocore/edk2/tree/master/IntelSiliconPkg/Feature/VTd [github.com]. So even if the OS isn't up yet DMA attacks are still locked out.

      Assuming you are running a recent OS and firmware, this is now a non-issue.

  • MB/s not Mb/s (Score:5, Informative)

    by Vairon ( 17314 ) on Monday February 25, 2019 @01:03PM (#58176892)

    microSD Express format supports up to 985 MB/s not 985 Mb/s.

    MB/s is megabytes (1,000,000 bytes) per second.
    Mb/s is megabits (1,000,000 bits) per second.

    References:
    https://www.sdcard.org/press/T... [sdcard.org]

    • by Rhipf ( 525263 )

      Technically a megabit is 1,048,576 bits but for marketing use they like to use 10 to the 6th power to represent a megabit (megabyte would be 1,048,576 bytes). I have no idea if they are using the true megabit in this case or the marketing megabit though.

  • limits (Score:5, Interesting)

    by blackomegax ( 807080 ) on Monday February 25, 2019 @01:06PM (#58176924) Journal
    NAND is limited by how many chips are stacked behind the controller. microSD is limited to a single chip. This is why, even with current 90MB/s rated microsd, you still get 7MB/s speeds from it once you fill up the controller buffer. NVMe on a single chip shitNAND? lol. this is pure marketing bullshit.
    • by MobyDisk ( 75490 )

      Why is MicroSD limited to a single chip? Is this a physicals space limitation?

      • There are some cards with more than a single flash chip inside them, but they are always full size sdcards.

        Here's an example.

        https://upload.wikimedia.org/w... [wikimedia.org]

        Most will only be a single chip though.

        The big bottleneck is the controller itself, which manipulates the flash. SDCard uses a serial protocol, not a parallel data IO direct to the flash chip. The flash chip could be hella fast, but if there is a cheap and slow controller driving it.. That's like putting an SSD on a SATA I interface.

    • Re:limits (Score:5, Interesting)

      by williamyf ( 227051 ) on Monday February 25, 2019 @02:17PM (#58177526)

      Until they begin making (micro)SD cards out of 3DxPoint, ReRam, Phase Changing RAM or Mermistors...

      You see, the (micro)SD format is not tied to Flash, therefore, the need to future-proof the bus...

      • Re:limits (Score:4, Informative)

        by thegarbz ( 1787294 ) on Monday February 25, 2019 @07:08PM (#58179354)

        Ignore the OP. He's buying cheap Chinese shit. Most reputable cards will happily max out the SD card's current bus for a sustained write across their entire capacity and despite his assertion that NAND is the limiting factor to 7MB/s you'll find most SSDs have either 2 or 4 NAND chips on them and happily crank out several gigabytes per second of data.

    • by tonywong ( 96839 )
      This is incorrect. Junk cards will exhibit the behaviour you claim, but genuine full speed UHS-II cards can hit (near) their claimed read and write speeds.

      This F-Stoppers video shows some 1.5GB transfers with times on various cards and readers. 88MB/sec write on a 95MB/sec claimed write speed.

      https://youtu.be/ZlWhvc-UCOA?t=500
    • NVMe on a single chip shitNAND? lol. this is pure marketing bullshit.

      Hmmm I have only 2 chips on my NVMe SSD and I can do 3400MB/s so as usual there is more to technology than counting the number of black things on the bigger thing that is plugged into the other thing.

      And I'm genuinely surprised. I think I have a 256GB SD card with a 256GB controller buffer on it. Who knew. After all I can sustain 88MB/s on my SSD card just fine when copying massive amounts of data to and from it. I guess all those people who actually record 4K footage also have those magical SD cards you've

  • It would be interesting to know the IOPS of the new cards, SD card latency is traditionally a fraction of embedded flash.

  • by Anonymous Coward

    Where nothing can possiblye go wrong!

  • Am I the only one who would want larger cards in exchange for similar speeds to desktop storage? Something about the size of Compact Flash, but with the ability to work as similar to an actual SSD found on a desktop or laptop. 985 Mb/s is quite slow in comparison to the 500 MB/s we have with desktop storage media. Maybe the power requirements are too high or there are other reasons it won't work. I'd love to be able to take a standard M.2 drive and stick in my phone or camera, even if we have to increase

  • by mykepredko ( 40154 ) on Monday February 25, 2019 @01:53PM (#58177326) Homepage

    When you see "985MB/s transfer speeds", I suspect that you're assuming that the card can read and write data at this speed all day long.

    But, I suspect that there are limits in terms of writing and accessing data. I'm sure burst speeds of 985MB/s is possible (with longer read bursts than write) but the overall/average speed will probably be 20-50MB/s, which is still very good, but not what you're being lead to believe.

    • Comment removed based on user account deletion
      • Interestingly the heat throttling of modern NVMe SSDs has nothing to do with the memory and everything to do with the controller. I would highly recommend a heatsink, and when you get the heatsink you want to apply the pad so it touches only the controller. NAND works better when it's hot which is why it has a minimum temperature rating.

I have hardly ever known a mathematician who was capable of reasoning. -- Plato

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