DragonFly BSD
DragonFly kernel List (threaded) for 2003-07
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Re: just curious

From: Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>
Date: Fri, 18 Jul 2003 21:16:01 -0700 (PDT)

:I think microkernels have moved on since mach, active projects
:like L4-descendents from Karlsruhe university (http://l4ka.org/)
:and fiasco from Dresden (http://os.inf.tu-dresden.de/L4/) appear
:to function quite well. I played around with those some weeks ago
:and was quite impressed (after being exposed to mach many years
:ago :-)
:What lacks in most u-kernel implementations is some meaningful
:userland "kernel." Moving stuff from the kernel to some kernel-ish
:process (for lack of a better word) seems useful to me. If I
:understand you correctly you're aiming at a best of both worlds
:approach: 'simple' kernel and delegating complex issues to userland?
:(millikernel? ;)

    My primary interest in userland kernel extensions, like a VFS layer,
    is to be able to implement complex features targeted to specific tasks
    (for example, a VFS environment to verify that a package depends on 
    only what we think it depends on).  I do not think there is much to be
    gained by moving major pieces of the kernel into userland.  The
    DragonFly design would allow that sort of work to be done, but it
    isn't a Goal.  I think that even after all the work is done
    DragonFly will still qualify as a monolithic kernel design.  Or perhaps
    someone will come up with a new name.

:Another question, how far does the messaging go, i.e. would it
:extend to something like network/grid computing?

    The core messaging, no.  With appropriate translation agents as the
    mp_SendMsg port functions, yes.  And that would likely be how we would
    implement such messaging.  At some point down the line when the caching
    model is working internally we *will* have to extend it across the
    network, and at that point we might come up with an API that deals 
    with the issues such an extension entails (like timeouts, failures,

					Matthew Dillon 

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