How can Minix 3 be so small

Wei Shen cquark at
Wed Jun 27 08:42:17 CEST 2007

On 6/27/07, Alan Grimes <agrimes at> wrote:
> The problem with L4 on the other hand is that it doesn't have an
> operating system wrapped around it in order to make it usable... I have
> a number of earth-shaking projects ...

Can you share some?

Got a counterexample of an installable and usable L4 development system?

I think L4Env or Kenge + Iguana can do some work, through they are not
mature yet.

IMHO (plese excuse me if it is not proper), we must have an
unified development environment to make L4 more attractive and get more

I think L4Env is easier to understand for new comers, however most parts of
the public release only support V2/X0 API, and there is never complete and
up-to-date documentation or roadmap. The organization of source tree is
confusing without a clear architecture. Various components and changes just
emerge from time to time.

I believe if L4Env can support X2 API and is reorganized / redesigned to
reflect an explicit system architecture with confusing legacy code
discarded, it will be much more popular and can greatly boost the
development of L4.

To me, Iguana is not good to understand, especially that there are much
ambiguity in the specification. It is more like an academic report than
a technical manual, and it seems that some concepts are still in development
and so hard to correspond to source code.
Moreover, Iguana is just a new single-address space "mono-kernel" in user
level, it provides only a basic set of services and is far from enough to
construct an usable system. We can not always rely on a virtualized Linux
which eliminates the advantage of a u-kernel. I know that the new Iguana
API is under development, however, again there is not a clear roadmap

It seems that both OS Group in TUD and ERTOS in NICTA focus more on their
new L4 API. IMHO, seL4 and L4.sec may be great work in academic sense (and
may relate to commercial considerations in future), but at present a strong
development environment for existing kernels and APIs may be more important
to expanding the influence of  L4, and better meet the appetite of most
open-source programmers (of course, these may not be what you concern).

As for Minix3, it grows fast since last year due to good organization and
open strategy that attracts open-source programmers. And I think maybe one
day, it will become more influential than L4 if things progress as now. An
successful system may not be the one do best in specific aspects, but should
be one that works.


Wei Shen
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