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  • BillBear - Thursday, August 3, 2017 - link

    Even if it isn't high performance for an NVMe SSD, I still find the size of that form factor amazing, however, I am old enough to remember 8 inch floppys.
  • abrowne1993 - Thursday, August 3, 2017 - link

    If the floppy is 8 inches I'd hate to see the hard disk.
  • Stan11003 - Thursday, August 3, 2017 - link

    https://www-03.ibm.com/ibm/history/exhibits/storag...
    They were the size of a mini fridge and cost up to $87K
  • edzieba - Friday, August 4, 2017 - link

    Gotta be careful with data access on those: if you were bored (or malicious), you could read/write data alternately on the inside and outside tracks of the platters, causing the (comparatively) massive R/W head arm to swing rapidly back and forth, and the whole unit could start to walk away on you.
  • bill.rookard - Thursday, August 3, 2017 - link

    The thing that would worry me, and I wonder if anyone thought this through....

    If it uses system RAM for hosting the mapping info for the LBA -> page map... what happens if the system:

    1) isn't using ECC and there's a bit error.
    2) has a typical misbehaving program which corrupts the LBA mapping.
    3) has a deliberately malicious program muck with the LBA mapping.
    4) loses power during a write.

    Any one of those three issues could create big problems with the drives and the stability of the system.
  • Billy Tallis - Thursday, August 3, 2017 - link

    The host memory buffer memory is supposed to be set aside by the OS for the exclusive use of the SSD, so cases 2 and 3 would require an OS/driver bug, not just a misbehaving application. (Or a successful DRAM rowhammer attack.)

    Any SSD using HMB must be prepared to immediately relinquish that memory back to the host system, so in practice HMB is used as a write-through cache, not a write-back cache. That means there's nothing worse about a sudden power loss when you're using HMB.

    Lack of ECC is theoretically a problem, but given the small amount of DRAM used for HMB, the expected error rate is really small and not a concern for most of the applications that would use this kind of SSD.

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