Re: Subsystem booting

[Marcus Brinkmann]

On Sun, May 25, 2003 at 12:17:36PM +0200, Niels Möller wrote:
> What should the subsystem boot procedure be like? Is the following
> close to right?
> 
> For each subsystem, there's one "subsystem-root" module. These are
> loaded by grub, after the rootserver.

No, there can be several modules per subsystem.  In fact, I am not sure I
want to worry about subsystems at all at this stage, but an argument in the
grub module command line can specify the subsystem.
 
> The rootserver allocates subsystem id:s, creates an address space for
> each subsystem, sets up itself as pager for the subsystems, and
> creates a thread in each subsystem server which starts executing at
> _start. It then starts to accept calls from privileged subsystem
> threads, and performs privileged L4 system calls on their behalf

About that.  Did you check out Neals l4hurd code?

> Each subsystem needs to somehow get some information from the
> rootserver, including the root server thread id (or is that fixed?),
> and boot arguments and GRUB modules.

The root server thread ids (one per CPU) might be fixed or not (don't know
yet).

> For the hurd, the task server needs another grub module for the first
> task(s), which could be something like serverboot (processing
> additional GRUB modules),

Serverboot is dead, man.

> The root server could also support have some ipc call for starting a
> new subsystem, later than boot time.

Not at all.  Subsystems are just numbers, the root server does not enforce
them or care about what the subsystems do with them.

Thanks,
Marcus


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Marcus Brinkmann              The Hurd http://www.gnu.org/software/hurd/
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