[Discuss] FreeNx

[John Blomfield]

Alan W. Irwin wrote:
> On 2007-11-22 08:23-0800 pw wrote:
>
>> John Blomfield wrote:
>>
>>> Thanks, I am beginning to get my mind around all of this.  I have 
>>> set about trying out all the options but I have been unable to get 
>>> freeNx and 2X servers to work.  Probably a combination of bugs in 
>>> the distro implementations and my incompetence. However, I have got 
>>> plain old vnc working perfectly. I found it relatively simple 
>>> compared to the others and a wealth of "how to's" around to help.  
>>> As yet I have not been brave enough to try your X server solution.  
>>> I realise that vnc is not secure but that hardly matters in my 
>>> limited home environment and I have an external firewall router.
>>>
>>> John Blomfield
>>
>>
>> If you don't wish to mess with the setting up the vnc server resolution
>> for each client you'd best get Alan to run you through the whole X thin
>> client thing. He does that stuff in his sleep.
>
> Probably... :-)
>
> Actually anyone can grok remote use of X clients in their sleep if they
> remember just one principle; X has a classical client/server architecture
> where the X server is always run on the local computer that has the
> monitor/mouse/keyboard attached while the X clients (e.g., KDE or GNOME
> applications) can be run on that computer or any other remote computer 
> that
> is accessible over the net.
>
> In the typical case of a Linux PC or laptop the X clients run on the same
> machine as the X server so people mentally merge the clients with the 
> server
> and forget that they are really completely separate.  More confusion is
> caused by people's preconception that a "server" is some honking 
> machine as
> opposed to a particular kind of software (and in the X case, the X server
> software can and often does run on the smallest machines available and
> not necessarily on the "server" machine).
>
> So, John, nail that above principle to your wall, and remote X clients
> become really easy to both understand and use.
>
> Let's say you have a box called chickadee (a slow 133MHz/64MB box 
> would do
> fine) where the X server runs and a high-speed box called raven where 
> the X
> clients run.
>
> Then on raven, configure the xdm X client to only respond to queries from
> chickadee.  (This is the "tough" part which takes maybe a few 
> minutes.) On
> chickadee configure X like you normally do (or leave it alone if it is
> already configured as in the normal case).  Then simply launch the X 
> server
> on chickadee by running
>
> X -query raven
>
> The chickadee user then gets a login prompt from xdm running on raven, 
> and
> from then on they are using the raven desktop (KDE in our case) at the 
> same
> speed as if they were sitting at the raven keyboard.
>
> Running remote desktops by taking advantage of the separation between 
> remote
> X clients from the local X server works so well that people think 
> there must
> be some complicated trick behind it.  However, it is just a nice 
> byproduct
> of a great choice of software architecture for X as summarized in the 
> above
> principle, and to set it up just takes a few minutes with configuring 
> xdm on
> the box where the X clients (the desktop software such as GNOME or KDE 
> apps)
> will be running.
>
Thanks, Alan for all the help and suggestions. I have saved the more 
detailed instructions in your email:
http://www.vlug.org/pipermail/discuss/2007-November/023909.html

and a some point will experiment with it.  I am reading around the 
subject since I like to understand what I'm doing rather than just 
follow cook-book instructions.  As yet I am not sure whether this 
approach will achieve the functionality I want for the type of tasks I 
routinely perform.  So far I like the interface that vnc provides, in 
that it displays on the client monitor the client's own desktop _and_ 
the remote desktop, and I can mouse click between them.  When moving 
files back and forth between the two computers using sftp or NFS you can 
observer both file trees on the same screen by adjusting the position 
and size of the windows in the normal way as if they were actually on 
the same computer.  Similarly if you were comparing the contents of, say 
two text files, you can display them side by side without actually 
moving the files from one computer to the other.  Unfortunately you 
can't copy and paste since you are working with different clipboards!!!

I can also install vnc servers on all machines so that I can display any 
computer desktop on any other desktop.  I think this is a different 
scenario to a number of thin (or thick) clients accessing a single 
dedicated server providing a powerful application server.

The other advantage to me is that I think vnc will complement my present 
KVM connection that I have to two of my computers, rather than replace 
it.  As I mentioned before I have set up my backup computer, which has 
two HD's, to have multiple partitions that provide not only backup 
partitions for my other computers but also spare partitions on which I 
can try out different Linux distributions.  This means that I need to 
install new distros from CD now and again.  KMV is the most convenient 
way to do this because initially one does not have a network connection 
until a base system is installed.

John Blomfield
> Alan
> __________________________
> 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
> __________________________
>