Note that the block aoe client driver doesn't give us any insight to this as it just has the following when setting up for an ATA ID command:

    /* set up ata header */
    ah->scnt = 1;
    ah->cmdstat = ATA_CMD_ID_ATA;
    ah->lba3 = 0xa0;

No comments on why scnt is set to 1 and further why lba3 is set to 0xa0, which I don't do either (one of my code review comments always highlights code like this with raw "magic" numbers and no comment as to why.. but I get that this is open source... ).