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  • Samus - Friday, May 31, 2019 - link

    Where is the DRAM cache buffer? Are they talking about the 32MB built into the controller or host provided RAM?
  • erinadreno - Friday, May 31, 2019 - link

    If u read carefully enough ull find out that it's a mock-up
  • Skeptical123 - Saturday, June 1, 2019 - link

    The title also says prototype and the photo looks like it's a physical device with smd components meaning if there was going to be a DRAM cache buffer there's a good chance it would be on this board. Samus question is very valid if you "read carefully" the title or look at the photos.
  • linuxgeex - Friday, May 31, 2019 - link

    ROFL, 32MB is such a small amount that it would only matter if you were attaching the drive to a microcontroller. That can barely be enough to run the flash controller's firmware. There's no RAM on the board so this is a DRAM-less controller making use of host caching.
  • leexgx - Saturday, June 1, 2019 - link

    teh WD/sandisk controller has about 10mb of ram built into the controller so they don't suffer from the penalty of been full dramless (this is on the new WD Blue ssds)

    most SSDs don't use Host caching (HMB and i would not buy one if it did as your trusting that your ram will be 100% error free)
  • linuxgeex - Monday, June 3, 2019 - link

    32MB of controller RAM is 256mb, so not sure why you are suggesting the WD/sandisk would somehow be superior. DRAM will always be on external chips. It makes no sense to fab DRAM at the node size of a controller's SOC, so they use SRAM instead. Using host caching is dangerous because of kernel lockups, hard resets, and power failures. It's nothing to do with memory being error free. If your host RAM is not error free then you will get corruption when the data is transferred from the unreliable DRAM, making the reliability of the storage is moot. If you care about that level of reliability then use ECC, dual power supplies, UPS, RAID 1/5 with battery-backed cache memory, use a journalling filesystem with write barriers enabled, lock your computer in a box so nobody can touch the reset button or insert a USB device.

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