Re: [OT] Why does X need so much CPU power?
(sorry, can't quote this one since it was an attachment on my side)
> This is more analagous to VNC than it is to X11.
Hm, compared to controlling the entire desktop or a single window, you are
right. But I was more referring to the way windows are transmitted over a
network. With VNC (have this to my LAN/DSL server, Win2k) I know it captures
the screen/windows on the remote side, optionally JPEG-compresses them and
transfers them as a bitmap. (And this sometimes works a whole lot faster
then an X session, both over mid/high speed networks.) WTS seems to transfer
not bitmap captures but rather the display 'commands' (don't know how that
works internally) so that it looks like a slightly delayed drawing of the
desktop as it could be locally. (This is only from what I believe I have
seen...)
> - Because the window manager, not the application, is aware of its
> location, position, and display status, if an application locks up,
> you can manipulate its windows yourself, rather than being stuck
> with a bunch of unresponsive rectangles on screen.
This has changed a little bit since Win2k. At least the close button IS
responsive. If a window doesn't respond to Windows' 'questions', you may
kill the app by clicking the X icon of the window.
> You have details on this last?
The program we use is called "Citrix Program Neighbourhood". It displays any
windows on the WTS server as they were on your computer, only with colours,
metrics and mouse pointers from the WTS. But I can't tell you more on that,
it was already installed on the image I got last time. I'm sure Google knows
more...
--
Yves Goergen
nospam.list@unclassified.de
Please don't CC me (causes double mails)
----- Original Message -----
From: "Karsten M. Self" <kmself@ix.netcom.com>
To: "Debian-User" <debian-user@lists.debian.org>
Sent: Thursday, September 04, 2003 11:02 AM
Subject: Re: [OT] Why does X need so much CPU power?
on Tue, Sep 02, 2003 at 08:51:22PM +0200, Yves Goergen
(nospam.list@unclassified.de) wrote:
> On Tuesday, September 02, 2003 8:00 PM CET, Erik Steffl wrote:
> > btw the overhead of client/server isn't anything that one needs to
> > be concerned about even on 386 (X with reasonable WM performs
> > same/better
> > as windows)
>
> Could be, yes (I don't know). Just as a note, Windows has the same
feature.
> OK, a similar one. You can connect to a remote desktop and see all
> applications/windows on your client. It's called 'Terminal Services' and
> works a bit like X connections.
This is more analagous to VNC than it is to X11.
In the case of WTS or VNC, the display and all clients live on the
remote side of the connection (I'll refrain from saying "server" given
X11's backwards client/server terminology). While you can export an
entire desktop, you cannot export a single application window (though I
hear rumors this is changing. Some remote admin clients for legacy MS
Windows (e.g.: radmin, and others like it) allow remote control of a
single desktop. Unlike these, WTS allows you to run several
simulataneous WTS sessions. However you cannot run multiple local
displays.
Contrast this to some of the capabilities of X11:
- Run a local window manager, but remote apps from one or more remote
systems.
- Tunnel these remote apps through a secure, authenticating,
encrypting tunnel via ssh.
- Run your entire X session off an XDMCP server (not secure, but
acceptable on a trusted network).
- Run two or more local X sessions. These can be toggled between with
<ctrl><alt><F[7890]> (ctrl, alt, and a function key), or you can
navigate directly with 'chvt'. Note that this is *not* fast user
switching. You're actually toggling between displays.
- Nested displays. Want to run a particular session in its own
window? Run Xnest and launch its own window manager and X clients.
Useful for demoing specific WM features.
- Move windows between different displays using xmove / xmovectrl.
- Switch window managers or desktop environments on the fly, without
killing your session (OK, so Microsoft now lets you kill and restart
EXPLORER.EXE on the fly). Every few weeks I may have to send
WindowMaker a SIGUSR1 to reset itself.
- Because the window manager, not the application, is aware of its
location, position, and display status, if an application locks up,
you can manipulate its windows yourself, rather than being stuck
with a bunch of unresponsive rectangles on screen.
The legacy MS Windows display model can only handle a very small subset
of these capabilities.
> Servers are available with Win2k Terminal Server or WinXP. Clients
> (also from third-party) work on any recent Windows. Some of them even
> display single windows on the 'server' as independant windows on the
> client desktop... nice feature.
You have details on this last?
Peace.
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