Re: additional questions

[olafBuddenhagen]

Hi,

On Tue, Dec 08, 2009 at 10:27:12PM +0100, Jakub Daniel wrote:

> I read a paper about mach not being the best choice of microkernel for
> hurd.

There are various comments to that effect floating around the net --
some well-founded, some myths...

> And I also know that viengoos has been in development for some time.
> What I hoped to find on the web was whether it (viengoos) is ment to
> replace mach if everything goes as expected (if viengoos is part of
> gnu project).

Viengoos is a testbed for some ideas about adressing certain concerns
found during Hurd development. So in a sense, it indeed caters to Hurd's
needs -- though I don't think Neal ever explicitely meant it to be a
replacement for Mach; but rather a research project, that *might* turn
out useful for the Hurd as well...

> As i took a look on the git repository of viengoos i found out that
> there have not been many commits since the beginning of this year, is
> it still being developed (actively).

No, unfortunately Neal changed his research focus. Nobody is working on
Viengoos anymore AFAIK.

> Would it be hard to switch from mach to viengoos (when it is ready)?

Depends on how it is approached. Probably it would be possible to create
some wrappers, so the existing Hurd implementation could be ported with
minimal effort. Making good use of Viengoos would require more
fundamental changes, though.

> Would it bring difficulties or would it be benefitial?

Both...

Viengoos addresses the shortcomings of Mach, but many of the ideas are
experimental, so it's hard to tell what it would bring. In either case,
it would require a considerable amount of work to do the initial port.

> I know this might sound a bit unrelated to this mailing list..

Not at all.

> but i have heard that hurd suffers from difficulties with mach..

It does in some areas. IMHO they are not the most urgent problems we are
facing -- but some people have a different opinion on that...

On Tue, Dec 08, 2009 at 11:13:15PM +0100, Jakub Daniel wrote:

> "From early on, the Hurd was developed to use GNU
> Mach<http://en.wikipedia.org/wiki/GNU_Mach>as the microkernel. This
> was a technical decision made by Richard Stallman, and one that he
> later saw as a mistake."

The mistake was in assuming that developing a multiserver system on top
of an existing microkernel would be faster than writing a monolithic
kernel from scratch.

I don't think RMS ever actually made a judgement on the merits of Mach
as a microkernel...

> even though i thought viengoos would bring newer drivers and support
> for various things that mach has not yed focused on.

Viengoos was never about drivers. That's an entirely different issue,
and pretty independent of the choice of microkernels.

(Zheng Da is presently working on the driver issue -- let's see how it
works out :-) )

> I also wondered if GNU/Hurd had some plan for future as other project
> have or due to the fact that there is lot of work on bugs that might
> yet occur it doesnt..
> 
> I mean whether there are some points when next release is made... some
> main revision versions with TODO lists..

Unfortunately, we do not have any roadmap. This is, in part, because
people have different visions about where the project should go...

-antrik-