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    SubjectRe: tools support for non-512 byte sector sizes
    Matt Domsch <> wrote:
    > On Tue, Jul 29, 2008 at 02:48:31PM -0400, Martin K. Petersen wrote:
    >> Just yesterday I received a couple of prototype drives in the mail.
    >> I'll ask the vendor whether they support 4KB and if so I'll give them
    >> a whirl.
    > I have access to disks with native 4KB sectors now too. Would

    Do they expose that sector size?
    I.e., does ioctl(fd,BLKSSZGET,&ss) set ss to 4096?

    I'm interested because I'm preparing GNU Parted's partition table
    manipulation code (not its FS code) for just that.
    In particular, now I've heard two stories:

    - disk makers will eventually sell drives with >512-byte sectors

    - some disk makers have sort of agreed not to do that, and
    expect forever to hide the larger underlying sector size
    behind a virtual 512 (of course, this imposes alignment
    restrictions, but that's a smaller problem)

    Even if the latter is the case, we still have to deal with
    optical and flash, both of which can already have larger sectors.

    > interested parties be willing to share test plans, so we could be sure
    > we have coverage wrt correctness: kernel internals, userspace tools like parted,
    > fdisk, kpartx, apps using O_DIRECT)? Benchmarking winds up being an
    > NDA activity this early in the game so I don't want the focus of any
    > joint work to be benchmarks yet.

    Speaking of O_DIRECT, both dd and shred (both in coreutils), use
    O_DIRECT, so you could get _some_ coverage just by running shred
    and experimenting with dd's oflag=direct and iflag=direct options.

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