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    SubjectRe: IDE freeze for seconds
    Johnny Tevessen wrote:
    >
    > Hi!
    >
    > I've got four IDE drives (hda..hdd). They're told to go to sleep
    > after a while. But when some application needs to use a file on one
    > of them, both the application itself and parts of the system (other
    > tasks) get frozen for some seconds if the given drive needs to spin
    > up first.
    >
    > I think this wait period should only affect the kernel fs thread
    > that tries to read from the hd, but not the applications?

    That might work if the FS ran on a separate thread.
    But under Linux, the "fs thread" *is* the application process.

    The reason other tasks may also be held up during the spin-up
    is that the disk-queue is blocked on the r/w request that
    caused the spin-up, and other requests for the same MAJOR
    (IDE interface) cannot proceed until it is serviced.

    Other IDE interfaces are free to continue working in parallel.

    --
    mlord@pobox.com

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