[Discuss] FreeNx

[John Blomfield]

Alan W. Irwin wrote:
> On 2007-11-20 11:05-0800 Michael wrote:
>
>> On Tue, 2007-11-20 at 10:49 -0800, Alan W. Irwin wrote:
>>
>>> On 2007-11-20 10:06-0800 Michael wrote:
>>>
>>>>
>>>>
>>>>> I think of FreeNX as a way to accelerate X communications over a low
>>>>> bandwidth high-latency network.  In practice, though, I find it is 
>>>>> not
>>>>> needed for typical home LAN speeds of 100Mb/s.  For example, for our
>>>>> thin-client configuration (X-terminal), we don't bother with it 
>>>>> because
>>>>> there is no noticable difference in X access speed locally or over 
>>>>> our
>>>>> 100Mb/s LAN.
>>>>>
>>>>> Let's call your boxes, box1, box2, and box3 ... // ...... simply 
>>>>> be a matter of
>>>>> hitting ctrl-alt-F7, ctrl-alt-F8, or ctr-alt-F9.  X networking 
>>>>> support is
>>>>> truly empowering!
>>>>>
>>>>> Alan
>>>>
>>>>
>>>>    Am I understanding this correctly? Can I actually operate various
>>>> headless systems via remote X sessions using FreeNX?
>>>
>>> Actually, that capability has been built right into X for decades so 
>>> there
>>> is no need to bother with FreeNX unless you are in a low-bandwidth
>>> (internet) situation.  100Mb/s LAN's have plenty of speed so the FreeNX
>>> complication is not required to run X applications (e.g., KDE) on 
>>> any of the
>>> boxes on your LAN with a monitor/keyboard mouse combination permanently
>>> connected to just one of them.
>>>
>>> Alan
>>
>>
>>    This is extremely interesting! The things I learn every day. What is
>> this functionality called? I have never researched the x server at all,
>> so I wouldn't have the first clue what to look for. I will start
>> searching under "remote X sessions", but if it actually has a specific
>> name, things will certainly go faster.
>
> This method is used to enable so-called thin clients or X terminals which
> run the X server (which controls the monitor, mouse, and keyboard) 
> locally
> and X applications (such as KDE or GNOME) remotely on a headless (but
> extremely powerful) box.  Normally, only one headless box is involved 
> when
> dealing with thin clients, but there is no reason why you cannot have 
> just
> one fat client (with thin client capability) displaying X application
> results from a number of headless boxes as well as X application results
> from itself.
>
> To give you some background, The city of Largo Florida has used the
> thin-client approach where the ~500 city employees use thin clients to 
> run
> GNOME on one central server.  Dave Richards is in charge there, and 
> you can
> read his blog (http://davelargo.blogspot.com/) to see how it is going for
> his second-generation 3D thin-client effort.
>
> Another X-terminal general reference is ltsp.org.  But that is focussed
> on all the details required for booting diskless thin clients, and 
> since you
> don't have to worry about diskless, you could get easily get lost in
> those details.
>
> Assuming you already have Linux running on all your headless boxes and 
> your "headed" box, all that is really required is to set up xdm (X 
> display
> manager) on each headless box, and to run "X -query" on your headed box.
> There is an X display manager entry for wikipedia at
> http://en.wikipedia.org/wiki/X_display_manager which gives you some of 
> the
> background.  I mentioned xdm configuration details in
> http://ladybug.vlug.org/pipermail/discuss/2007-November/023941.html.  
> Those
> details are quite simple.  But you should also consult the xdm man 
> page as
> well since some of those details might be set up differently on your
> particular distribution.
>
> There are other X display managers than xdm (e.g., gdm, kdm, ldm), but 
> to my
> mind they all overcomplicate a simple task (to respond over the 
> network to X
> -query).  So I far prefer xdm over the others.
>
> Alan
I am still trying to decide how best to proceed with my three boxs, that 
is, X-xdm, freeNx or some other but I have a question about the X-xdm 
route.  If once you've setup your X headless server and the network 
connection to the thin (or fat ) client is broken can you still plug a 
keyboard, mouse and monitor into the server and get it to work, now that 
you've modified the display manager??

John Blomfield


> __________________________
> Alan W. Irwin
>
> Astronomical research affiliation with Department of Physics and 
> Astronomy,
> University of Victoria (astrowww.phys.uvic.ca).
>
> Programming affiliations with the FreeEOS equation-of-state 
> implementation
> for stellar interiors (freeeos.sf.net); PLplot scientific plotting 
> software
> package (plplot.org); the libLASi project (unifont.org/lasi); the 
> Loads of
> Linux Links project (loll.sf.net); and the Linux Brochure Project
> (lbproject.sf.net).
> __________________________
>
> Linux-powered Science
> __________________________
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