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I meant the controller that manages the NAND cells, I assumed it would be called NVMe controller. Essentially the IC that the "NVMe controller" in your image ta

I meant the controller that manages the NAND cells, I assumed it would be called NVMe controller. Essentially the IC that the "NVMe controller" in your image talks to.

paulmd 4y ago
That would normally be called a "flash controller" and yeah, of course that lives on the SSD. (unless it doesn't - eMMC doesn't normally have a flash controller and you just do direct writes to the flash cells... as do some IOFusion PCIe cards that are just flash directly attached to PCIe with no controller. Sometimes that functionality is just software-based. Flash cards (eg microSD) usually also do not have a flash controller directly either.) Anyway, it's true though that Apple does push the flash controller functionality into the SOC while AMD does not, Apple implements their SSD in a non-standard fashion, that's why it's not compatible with off-the-shelf drives. The flash is just flash on a board, I don't even think it's NVMe compatible at all either. So if you want to be maximally pedantic... neither does Apple implement onboard NVMe controllers, just flash controllers ;)
- deleted 4y ago
  [deleted]
- rowanG077 4y ago
  Apple uses NVMe. It's just not over PCIe. It uses a proprietary mailbox interface. Which is fine since NVMe is transport agnostic.
- wtallis 4y ago
  FYI, all current flash card formats have the equivalent of an SSD controller, implementing a Flash Translation Layer. Exposing raw NAND was somewhat viable in the very early days when everything was using large SLC memory cells (see SmartMedia and xD-Picture Card), but no current format could remain usable for long without wear leveling. If you can use standard filesystems and access the drive or card from multiple operating systems, then it must be providing its own FTL rather than relying on the host software for wear leveling. The above also applies to eMMC and UFS storage as found in devices like smartphones.

I meant the controller that manages the NAND cells, I assumed it would be called NVMe controller. Essentially the IC that the "NVMe controller" in your image talks to.

paulmd 4y ago

That would normally be called a "flash controller" and yeah, of course that lives on the SSD. (unless it doesn't - eMMC doesn't normally have a flash controller and you just do direct writes to the flash cells... as do some IOFusion PCIe cards that are just flash directly attached to PCIe with no controller. Sometimes that functionality is just software-based. Flash cards (eg microSD) usually also do not have a flash controller directly either.) Anyway, it's true though that Apple does push the flash controller functionality into the SOC while AMD does not, Apple implements their SSD in a non-standard fashion, that's why it's not compatible with off-the-shelf drives. The flash is just flash on a board, I don't even think it's NVMe compatible at all either. So if you want to be maximally pedantic... neither does Apple implement onboard NVMe controllers, just flash controllers ;)

deleted 4y ago
[deleted]
rowanG077 4y ago
Apple uses NVMe. It's just not over PCIe. It uses a proprietary mailbox interface. Which is fine since NVMe is transport agnostic.
wtallis 4y ago
FYI, all current flash card formats have the equivalent of an SSD controller, implementing a Flash Translation Layer. Exposing raw NAND was somewhat viable in the very early days when everything was using large SLC memory cells (see SmartMedia and xD-Picture Card), but no current format could remain usable for long without wear leveling. If you can use standard filesystems and access the drive or card from multiple operating systems, then it must be providing its own FTL rather than relying on the host software for wear leveling. The above also applies to eMMC and UFS storage as found in devices like smartphones.