Re: userland access to devices is moving!

From: Matthew D. Fuller (fullermd_at_over-yonder.net)
Date: 06/18/03

  • Next message: Poul-Henning Kamp: "Re: userland access to devices is moving!" 
    Date: Wed, 18 Jun 2003 12:47:33 -0500
To: Poul-Henning Kamp <phk@phk.freebsd.dk>

    On Wed, Jun 18, 2003 at 05:35:19PM +0200 I heard the voice of
    Poul-Henning Kamp, and lo! it spake thus:
    >
    > I sat down and hacked up a simple prototype to test the concept I
    > have been rambling about for some years: Going directly from
    > filedescriptor to device driver thus bypassing the vnode, devfs and
    > specfs layer.

    Speaking as somebody whose reach of mailing lists notably exceeds his
    grasp (as it always should be; otherwise what fun is it?), I often find
    myself a little in the dark on what these sort of things really /mean/ to
    the system in the end, and I think it would be a nice extension of these
    sort of posts/proposals to have a sentence of summary, along the lines
    of:

    What does this change /mean/ to the system as a whole? Is this
    A) Cleaner code, so bugs can be found and fixed quicker and better,
    B) Architectural improvement, so new features are easier to add on
       cleanly and well, or
    C) A real-world performance improvement. The benchmark you posted
       certainly shows a significant improvement in SOMETHING; but is it a
       something that will make mail servers or web servers or file servers
       or workstations perk up?

    I realize that they're not really exclusive conditions, and are mostly
    intertangled. And, for that matter, that most changes don't get done
    because of A, B, C, or any combination thereof, but more often because
    "This is the ugliest mess I've ever seen and it's been haunting my dreams
    for years, and I anyway I thought it would be fun to mess with." But I
    for one would appreciate a quick note of a higher-level view of where
    this can move us.

    Of course this means I'm out of my depth. But everybody needs a hobby
    :-} 

    -- 
Matthew Fuller     (MF4839)   |  fullermd@over-yonder.net
Systems/Network Administrator |  http://www.over-yonder.net/~fullermd/
"The only reason I'm burning my candle at both ends, is because I
      haven't figured out how to light the middle yet"
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