Ultrix 4.2

[Ted Lemon]

In article <984 at lhdsy1.chevron.com> yzarn at lhdsy1.chevron.com (Philip Yzarn de Louraille) writes:
>In article <MELLON.91Jun18142804 at nigiri.pa.dec.com> mellon at nigiri.pa.dec.com (Ted Lemon) writes:
>>
>>without it.   Plus, the MIT server doesn't do multiscreen.
>   C'mon! Do you think the DEC server does multi-screen? It really does
>   not, it emulates multi-screen!
>   You need to run a window manager per screen you are using and you cannot
>   move a window from one window to another. I do not call this a
>   multi-screen server, not by a long shot, especially after seeing a
>   *real* multi-screen machine like the Mac.

Actually, no.   Twm, mwm and dxwm all support multi-screen displays.
The reason you can't move windows from screen to screen is because the
screens are considered distinct by the X protocol - an application
can't be told through the X protocol that it should free all its
resources and reallocate them on a new screen, and there's no clean
way to do that freeing and reallocation process anyway.

It would be possible to implement an X server that considered multiple
physical screens to be the same virtual screen, but there are problems
with this.   For one thing, in order to avoid violating the X protocol
specification, you would have to make the colormaps on both screens
identical.   This would mean that an application on one screen
changing the colormap would affect applications on the other screen.
Another problem is that you can theoretically support frame buffers
with different depths, and the X protocol doesn't define any way to
say that a certain portion of a screen is monochrome, while another
portion is colour.

That said, I agree that it would be nice to have the choice between
the current implementation and some version of the implementation that
I described above, where you are constrained to using frame buffers of
the same depth, and where such frame buffers have their colour tables
kept in sync.   I had heard at one point that an MIT grad student was
hacking such a server, but I haven't heard anything about it for quite
some time.

Finally, this doesn't seem like a good excuse for DEC-bashing.   At
least we support the form of multiscreen that the X protocol is most
receptive to.   Many of our competitors do not.   The current X
Consortium release does not.   If you want to bash DEC, I'm sure you
can come up with something much more compelling - plenty of other
people on this newsgroup have been successful at it in the past.   :')

			       _MelloN_