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    SubjectRe: [ANNOUNCE] udev 0.1 release


    Arnd Bergmann wrote:

    >Greg KH wrote:
    >
    >
    >
    >>On Fri, Apr 11, 2003 at 01:29:57PM -0700, Steven Dake wrote:
    >>
    >>
    >>>It gets even worse, because performance of hotswap events on disk adds
    >>>is critical and spawning processes is incredibly slow compared to the
    >>>performance required by some telecom applications...
    >>>
    >>>
    >>It's critical that we quick name this disk within X milliseconds after
    >>it has been added to the system? What spec declares this?
    >>
    >>
    >
    >While the problem might not really be the per-device latency, what should
    >be handled correctly is the following scenario:
    >
    >- Someone accidentally removes the cable that connects a few hundred
    > (mounted) disks
    >- The cable is replaced, but - oops - to the wrong socket
    >- The person notices the error and now places the cable into the right
    > socket.
    >
    >At this time we have four concurrent hotplug events for every single
    >disks that we want to be finished in order and we want every disk
    >to end up with its original minor number in the end. If this is not
    >possible, the system still needs to be in a sensible state after this.
    >
    >
    Yes, and in the rest of my email, I stated this would be solved by
    replacing /sbin/hotplug with a mechanism to communicate events to a user
    space daemon which would process requests in order as submitted by the
    kernel. (All except the same minor/major, which may or may not happen).
    If the kernel is evil and doesn't submit events in order, thats another
    problem to solve, but it should for disk events, atleast.

    > Arnd <><
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