From: mouse@thunder.mcrcim.mcgill.edu (der Mouse)
Subject: Re: X-server multi screen
Organization: McGill Research Centre for Intelligent Machines
Lines: 42

In article <1qlop6$sgp@sun3.eeam.elin.co.at>, rainer@sun3.eeam.elin.co.at (Rainer Hochreiter) writes:

> I've seen a lot of different terms, which seem to mean the same
> thing.  Who can give an exact definition what these terms mean:

> 	-) multi-screen
> 	-) multi-headed
> 	-) multi-display
> 	-) X-Server zaphod mode

As applied to servers, the first three are fuzzy terms.  "multi-headed"
tends to be used for any system with multiple monitors, sometimes even
multiple screens even if they're multiplexed onto the same monitor (eg,
a Sun with a cg4 display).  "multi-screen" and "multi-display" would,
if taken strictly, mean different things, but since the strict meaning
of "multi-display" would refer to a system with multiple keyboards and
pointers, when it's used it probably refers to the same thing
"multi-screen" would: a system that provides multiple Screens.

"zaphod" is a term applied to the way the MIT server switches the
pointer from one screen to another by sliding it off the side of the
screen.

> Is there a limit how many screens/displays a single server can handle
> (in an articel a read something about an upper limit of 12) ?

There is a protocol limitation that restricts a given Display to at
most 255 Screens.  I know of no server that handles multiple Displays
on a single invocation, unless possibly my kludges to the R4 server can
be looked upon as such; on a TCP-based system there is necessarily a
limit of 65535 Displays per machine, but this is not a limitation
inherent to X.

What you read was most likely talking about a limit in some particular
implementation (probably the MIT one).  If it claimed there was a limit
of 12 inherent to X, the author of the article had no business writing
about X.

					der Mouse

				mouse@mcrcim.mcgill.edu
