Re: NSPasteboard on X, what to do?

[Pascal Bourguignon]

> Date: Thu, 10 Jan 2002 07:55:22 +0200 (EET)
> From: Dan Pascu <dan@services.iiruc.ro>
>
> On  9 Jan, Pascal Bourguignon wrote:
> >> I was being stupid because I allowed myself to be trapped into the
> >> model you presented where machines and screens are separate ...  the
> >> solution is trivial if you say that each screen is associated with a
> >> machine.
> >
> > That's  not the case.  You may  have several  X-server running  on one
> > machine, each with several X-displays to various persons.
> >
> >                             +-------------------+
> >                             |    Machine 1      |
> >            +-----------+    |                   |
> >         o  |Screen  11 |-\  |  +-----------+    |
> >        /O\ +-----------+  \-|--| Server 1  |    |
> >        / \ +-----------+  /-|--|=Display 1 |    |
> >            |Screen  12 |-/  |  +-----------+    |
> >            +-----------+    |                   |
> >                             |                   |
> >                             |                   |
> >                             |                   |
> >            +-----------+    |                   |
> >         o  |Screen  21 |-\  |  +-----------+    |
> >        /O\ +-----------+  \-|--| Server 2  |    |
> >        / \ +-----------+  /-|--|=Display 2 |    |
> >            |Screen  22 |-/  |  +-----------+    |
> >            +-----------+    |                   |
> >                             +-------------------+
(I've corrected terminology to match X).

> This is correct, with some observations:
> 1. server 1 and server2 cannot be active at the same time (you will
>    either have to switch between them as between virtual consoles with
>    Ctrl+Alt+Fnn, or one will run inside a window connected to the
>    other, but unless you move mouse in that window, the second server
>    will be idle, and this is a virtual server anyway).

Not if  you have several  physical monitors and  map the X  screens on
them. My diagram represents a quad-headed system.

> 2. Display11 Display12 and 21 22 are actually called screens by X
>    the combination Server1+Screen11+screen12 is one X display, and the
>    other is another display.

True. I stand corrected.

> 3. on a physical computer 2 guys cannot use X at the same time, so only
>    one X session (read DISPLAY) is active at a time, and they cannot
>    share any resources anyway when they switch from one to another by
>    using X event communication mechanisms.

One display (= one server) can  effectively serve only one person at a
time.  But nothing  prevent you  to run  several displays  (= severals
servers) managing different monitors and keyboards/mice, thus having a
multi-user computer.


Nowadays, even PCs can have several monitors and several USB keyboards
and mice.  But I'm thinking  more of big  iron such as  Linux/S390, or
specialized applications where having several workstations on the same
computer would be useful.

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