Re: just curious

[Ebo <dragonfly@xxxxxxxxxxxxxxxx>]

Matthew Dillon wrote:
> :Hi Matt,
> :
> :
> :I Hope the project works out. It's ambitious but it
> :sounds promising!
> :
> :Do you plan to work toward something like a
> :microkernel-ish system? Some statements on the site
> :seem to implicate this.
> :
> :E.
>
>     Well, the traditional definition of a microkernel has a lot of negative
>     connotations, which I blame on Mach.  DragonFly is definitely not going
>     to be a traditional microkernel but it will retain many of the better
>     qualities of a microkernel design.
>
>     For example, DragonFly will use messaging heavily but the messaging will
>     be a light-weight design that is, by itself, incapable of transiting a
>     protection boundary.  The core messaging structures will not track 
>     pointers or message sizes, for example.  Instead what we will do is
>     support the transiting of protection boundaries by creating port
>     abstractions which do the appropriate translation into and out of forms
>     that *can* cross a protection boundary.
>
>     In otherwords, we will be able to use messaging to be able to abstract
>     certain devices and VFS layers into userland, which is tradtionally 
>     considered to be 'microkernel design', but that abstraction is not going
>     to hogtie in-kernel implementations with overhead bloat nor are we going
>     to require protection separation for the majority of devices in what
>     would be considered a 'production' system.
>    
> 					-Matt
> 					Matthew Dillon 
> 					<dillon@xxxxxxxxxxxxx>

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? ;)

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


E.