Unified video+print Xserver / was: Re: Modularization mailing list and initial strawman proposal

[Roland Mainz]

Kevin E Martin wrote:
> > And print drivers as the Xprint DDXs should be turned into loadable
> > modules (in the long term the Xprt server is going away then[1],
> > replaced by a Xorg server which can handle both video and print modules
> > similar to what the Xserver in HP/UX can do today).
> >
> > [1]=or more correctly: Xprt isn't going away as it's still needed as
> > all-in-one X print server, however sepcial-purpose DDX like the SVGprint
> > DDX may only be available as loadable module.
> 
> Interesting idea.  Have you written a design document yet?  These ideas
> should be discussed in the Architecture Working Group.

The all-in-one video-print Xserver was always there since X11R6.3. It's
just hidden away in on of the build options in xc/config/cf/X11.tmpl.
AFAIK it was originally debated and favored by one of {Sun, HP} but I do
not remember the details anymore. One side was favoring per-user Xprint
servers (e.g. one per user and therefore an integrated (or sometimes
called "unified") solution) and the other side "global" ones with a
seperate print server (which is less resource hungry on multiuser
systems (Xterminals, SunRay etc.) and allows to run the Xprint server on
the print server machine directly instead of having each workstation
running it's own copy). In the meantime (e.g. since X11R6.3) HP added a
third option for HP/UX - having one Xserver which can either run in
video mode OR (=XOR) print mode (I am not sure whether it allows having
both video and print screens running at the same time like the current
Xorg code allows).

We have three goals here:
1. One option should be to have a seperate standalone Xprt server with
only builtin drivers (mainly for embedding purposes or in cases when not
all drivers are needed (for example the SVGprint driver is huge and
should only be available as loadable module))
2. Allow Xorg to load print DDXs dynamically 
3. Run the Xorg server either in video, print or a mode where a display
has both video and print screens.

The current status looks like this:
[1] is the default since X11R6.3
[3] is mainly available since X11R6.3 except that there is currently no
way to force the server into video-only or print-only mode - the Xorg
server just runs with all DDXs it can initalise and that's all (e.g.
we're lacking the -servermode option of HP's Xserver).
[2] is the most difficult part and needs special care to avoid later ABI
updates just because we forgot something (at some point HP could help
here via contributing their knowledge as the Xserver in HP/UX loads the
print DDX dynamically, too)

Comments/suggestions/etc. welcome... :)

----

Bye,
Roland

P.S.: Please keep the Xprint mailinglist <xprint at mozdev.org> in the CC:
as AFAIK not everyone there is subscribed to xorg-arch, too...

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