Re: L4Mach or Refactor Hurd Servers?

[Ian Duggan]

> People keep saying they think the Hurd is "deeply wedded" to Mach IPC.  I
> think all those people are just not really looking at the fundamentals of
> the Hurd code.  Yes, we use MiG RPC presentations and Mach port operations.

This is very likely in my case. I am still new to the code and am soaking in all
the details as a I go. I'm asking more in the vein of seeking to understand
where the Hurd stops and Gnumach starts. I concede that my current knowledge of
this is very minimal.

> rights and disconnected RPC).  We have always been opening to redesigning
> parts of Hurd implementation to fit better with different IPC systems.
> Noone has ever gotten specific about what they want to do.  I'm not sure
> that I'm on the l4-hurd list, so perhaps there has been some discussion
> there that I haven't seen.  But every time someone posts to bug-hurd with
> their opinion about the Hurd's relationship to Mach, they speak in
> completely vague general terms and never present anything concrete about
> the details of the IPC system they'd like to work with, how they would
> adapt the Hurd to use it, and what the problems might be.

If there has been any discussion, it was before I was on the list as well. I am
not asking for redesigns or anything of that sort. I don't have any input as to
what would be good or bad in that respect either. I might after I have done more
work with the code.

> As to your specific question, I can't imagine that anything you might call
> "L4Mach" would be a worthwhile thing to do from a Hurd perspective.  But I
> am only guessing what you really have in mind, since you have not been at
> all specific.

Apologies for the lack of information. My goal is to build a Hurd system that
can run using an L4 microkernel. I see two basic options for doing this:

1) Create a /boot/gnumach.gz that uses L4. No changes to the Hurd code.

2) Supplant /boot/gnumach.gz with an L4 microkernel and rework the Hurd
libraries to use L4 features where they currently use gnumachs'.


I understand what would be required for (1) better, so initially it seems
attractive. However, as you pointed out, I don't see how useful that would be as
a resulting system. I think I will work on (2) and see where I can get to.

-- Ian

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Ian Duggan                    ian@ianduggan.net
                              http://www.ianduggan.net