Re: object management and IPC a bit more formal

[Ludovic Courtès]

Hi,

On Tue, May 06, 2003 at 10:27:55AM +0200, Niels Möller wrote:
> Ideally, you will only have one mechanism for persistent objects, and
> the subsystem id has to be chosen at install time (or earlier).
> Persistent processes won't survive a change of the subsystem id for
> the persistant subsystem.
> 
> The allocation of subsystem id:s should be stored somewhere on disk.
> The allocation of PID:s in the persistent subsystem should also be
> stored on disk, I guess.
> 
> Does this solve the problem?

Well, that does solve the problem of subsystem IDs allocation.  However,
on 32-bit arches, there would be just a few bits (2, 3 or 4 according to
Marcus' proposal) of thread IDs dedicated to subsystem IDs.  This leaves
us with just a few subsystems.

Now, suppose we want each user to be able to choose whether he wants to
create his own persistent environment (running several persistent tasks)
or not: We may quickly need more than 8 subsystems.  Of course, if we
consider that there would only be one persistent subsystem, then
subsystems IDs are not a problem anymore.

Thanks,
Ludovic.