Re: local vs global object IDs

[Marcus Brinkmann]

On Tue, Jun 03, 2003 at 03:53:11PM +0200, Ludovic Courtès wrote:
> Note that global IDs may cause troubles if they are used within a
> persistent task as we discussed it some time ago [1].

I am aware of your concerns.  However, I don't think that in this case there is
a relationship to that discussion.  The global or local object ID component
is completely implemented within a server.  A persistent server will preserve
local _server side_ IDs as well as global server side IDs.

The issue you raised in your mail was about using global identifiers that
are not under the direct control of the server, such as its thread IDs.

For my taste it is already difficult enough to ensure that you always talk
to the same task, without servers changing their identity under your nose.
I think the most promising suggestion that was done in the past discussion
was to reserve a bit in the thread number and version ID field (effectively
separating the thread and task ID space) for persistent tasks and always make
sure that they get the same thread and task IDs (this only requires
special support by the task server).  This does not directly allow for reliable
communication between persistent and non-persistent tasks, though, and I
have no idea how to solve that (if it even is an issue).

Thanks,
Marcus


-- 
`Rhubarb is no Egyptian god.' GNU      http://www.gnu.org    address@hidden
Marcus Brinkmann              The Hurd http://www.gnu.org/software/hurd/
address@hidden
http://www.marcus-brinkmann.de/