Using X on the Intel Manycore Testing Lab?

Using X on the Intel Manycore Testing Lab?

If youve used X before you may already know that its a conduit crammed with data that can wreak havoc on many 21st century data connections. Over the years Ive actually talked with folks who have even tried X over dial up, for various reasons! (Note: not on the MTL, of course: thats not possible.)

Heres how that conversation ALWAYS goes by the way, in case youre curious:

Me: So, you tried X over dial up, eh?

Them: Well, ONCE

You get the point: you can do it, but it is dirt slow; nobody ever tries it twice. Turns out X over the MTL can have a similar chilling effect, even without the dial up part, depending on where you are on the globe and how your internet is faring. And if youve worked with X before, these statements do NOT surprise you. In general, around here we like to discourage users who want to try X with the MTL, and as a result its just not supported.

Why? Well, its slow at best and unusable at worst, which are the the usual problems any data-rich stream of content over secure remote access can have. All this said I wanted you to know you CAN do it; it is absolutely possible. Not sure why you would ever want to, especially if you dont live in the USA which is home base for the hardware and its network. But, just in case you want to try it sometime, see for yourself, the point of this posting is to show you one approach that actually works. Honest.

Before we get started, remember that in the world of X anything that controls an X display and brings it to you, say, on your laptop, is called an X Server, or to be even more precise, a PC X server. That means that the application which is actually running on the MTL server, whose display is now on your laptop, is known as the X Client, even though the server is handling all the processing of the application. Most people get this backwards, so, lets agree right now not to do that.

For those of you with adventurous spirits, heres the bare outline of how to get X going:

1) Make sure you are able to connect in a good ol normal remote connection first, as described in the Getting Started Guide

2) Get vncserver software running on the MTL in your account

3) Run your secure PCX server software on your laptop

4) Make the connection, run the default X apps plus any others you want

You may agree this doesnt look too complicated. Lets look at these steps in more detail now.

1) Make sure you can connect to the MTL.

The Getting Started Guide for the Lab describes several common ways to get connected. Make sure you can do that before you even think about trying X. Remember, this forum is a great place to discuss any connection problems you may run into along the way, if any. Of course you can always mail problems directly to as well.

If you are interested in running X as I do: I use PuTTY to make my initial connection, entering your username and password as always. The Getting Started Guide also talks about using F-Secure, and well look at that as well in step 3 below.

2) Run vncserver

Once you have logged in to the MTL using PuTTY or F-Secure, you have to run some remote control software that is designed to let X work with the labs security and the computer youre using to connect with. That remote control application is called vncserver and you run it from the command line:

$ vncserver

If you want to know more about its options, give the man page a try:

$ man vncserver

When you run vncserver you will notice that the software creates a hidden subdirectory in your HOME directory for its own use called .vnc. It also starts some processes that will manage your upcoming X session, and, assigns your user account a display number so your PCX server will know what to talk to.

Inside the new subdirectory youll see a filename ending in .pid that tells you vncserver is in fact up and running on your behalf. You will also see a file that ends in .log, which is a repository log file for vncserver activities.

$ ls $HOME/.vnc


In the above example, DISPLAY number 6 has been assigned for your use by the vncserver software. You might think of the filenames in this general format, where x is some number assigned to you when you start vncserver:


Youre probably getting the impression that x increments when different users start vncserver, and youd be right. When you do this, you may get 6, you may get some other integer. Be sure to write it down so dont forget it.

When you log on and off of the MTL, vncserver continues to work for you, and those two files will normally still exist the next time you log in. However, if the MTL is rebooted for administration or other reasons, when you log in the next time, you will have to restart vncserver, and you may or may not get the same number for your DISPLAY.

If sometime you log in to the MTL and are wondering if vncserver is still running for you or not, just check for the .pid file in the .vnc directory. If its there, its running.

If you want to manually stop the vncserver that is running for you, use this kill command (you can also see it in the man page), where x is once again the display number you got when you started it up.

$ vncserver kill:x

Or in our sample case:

$ vncserver kill:6

But once you have vncserver running, you can startup your PCX software per step 3 which follows; but be sure to leave this connection window up. Dont log out or close it down when you proceed.

3) Running the PCX software

There are two options here which seem to work quite well (probably more as well: if you find any, be sure to post what you find here at the forum). Im told that Xming works nicely, but Im partial to VNC Viewer myself, so thats the one Ill describe right now.

For X Windows to work you have to configure PuTTY (or F-Secure, if thats your favorite) for your new X display values, and run the VNC Viewer.

a) Configure PuTTY

Youve configured PuTTY already to get connected to the MTL, per the advice you got in the Getting Started Guide. Now, youll need to also configure Tunnels. Remember that x below is the integer that represents the display number that vncserver gave you when you ran it in step #2 of these instructions.

PuTTY -> Configuration -> SSH -> Tunnels

Source Port: 5590x

Destination: acano01:590x

Or, to use the example of 6 established earlier, thus:

PuTTY -> Configuration -> SSH -> Tunnels

Source Port: 55906

Destination: acano01:5906

When you make these changes, dont forget to ADD then SAVE this PuTTY profile.

b) Configure F-Secure

If you use F-Secure instead of PuTTY, youll need to add a new Local Forwardings, thus:

F-Secure -> Profiles -> Edit Profiles -> Local Forwardings -> Add

Source Port: 5590x

Destination: acano01

Destination Port: 950x

Save this new profile

Using our example of vncserver display 6, then wed have:

Source Port: 55906

Destination: acano01

Destination Port: 9506

Save this new profile

That should do it. All you have left to do is make the X connection.

4) Make your X connection

a. There may be several clients that work, but the one I use is VNC Client which you can find here:

b. After you install VNC Client, set your server address to, where again, x is the number of the display you were assigned in step 2. In our sample case,

c. When you connect, you will be prompted for your MTL password for access; be sure to provide it.

Once your X Session and XDesktop has started youll notice a nice simple xterm comes up, running twm, and you can left mouse click your way to running more xterms and any applications you wish.

If you prefer to try Xming rather than VNC Client, reports here are that it doesnt require as much customization to work time after time.

Remember, for the process Ive described above, if for any reason your vncserver is stopped and must be restarted, you may end up with a different value for your display for example, a 2 instead of the 6 weve been using here and that means youd have to go through the configuration steps again using that new display number in order to get your X Session started again. It only takes a few moments, but, if you dont do it, you will absolutely NOT get a session started.

If youre reading this post and are using Xming, please feel free to let the rest of the community know what you think of it.

Remember: using X on the Intel Manycore Testing Lab is not advised or supported. But if youre the curious type, these instructions will absolutely get you going.

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Great posting Jeff...

Note that X is onlyfunctional onthe login node (acano01), it is not available on the batch nodes as they are allat runlevel 3.

Here's another (possibly simpler)approachfor running X applications on the MTL, from a Windows platform. Please don't try to run any Linux desktops, as you'll find it painfully slow. And again as Jeff said before, we don't encourage the use of X on the MTL, and it's typically not supported.

So let's get started with this using Xming...

Xming is a free x-windows server available through sourceforge:

Assuming, you have PuTTY already installed, if not PuTTY is available at

Once you've downloaded Xming:

launch the setup executable.

Click Next >.

Select an installation directory and click Next >.

Choose Full Installation and make sure Normal PuTTY Link SSH client is selected; then click Next >.

Choose the Start Menu folder and click Next >.

Select any icons you wish to have created and click Next >.

Ensure all the installation information is correct and click Install.

Wait for the installation to finish.

If you wish to launch Xming now, leave Launch Xming checked. Click Finish to finish the installation.

To launch Xming at a later time, from the Start menu choose Programs (or All Programs) > Xming > Xming.

Note: Xming doesnt open any windows, it simply shows up as an icon in the notification area of the task bar (the area with the clock).

If you already have a PuTTY session configured for MTL (ensure you have Enable X11 forwarding checked in: Connection->SSH->X11 for this session)then login and run any X-enabled program (e.g., xclock). A new Windows window appears, which is automatically positioned by the Windows window manager.

That was easy, right?

Thanks for the info Jeff. I am trying to connect through a vncviewer to a Linux MTL machine. I have a vncserevr running on acano01. I have setup the local forwarding as in our info also. I am unable to connect with my vncviewer.
Any help would be greatly appreciated.


Trust youve configured (Putty), with the correct Connection->SSH->Tunnel

Source Port: 5590x

Destination: acano01:590x

Where x = the display # from vncserver

You mustthen use (Putty), to connect and log-in to the MTL with the above tunnel specified- make sure you saved it.

Then run your VNC viewer to server address:

Where x = the display # from vncserver

And enter your MTL password.

You should then get a X window with a shell.

Boy you can say that again, Mike.

I just upgraded my work system to Windows 7 and thought I'd give this approach a try, and I couldn't believe how simple Xming is.

Thanks for suggestion, GREAT way to go.


I have questionmy x is 28not 6sowhen configure F-securei can't use

Source Port: 559028

Destination: acano01

Destination Port: 95028

0r use

Source Port: 55928

Destination Port: 9528

this is correct or not


the latter, i.e. 55928 and use5928

when i use this x value in vnc get error in connection

I have problem
when I ls vncserver on F-secure it return[dasayed@acano01 ~]$ ls $HOME/.vncacano01:28.log acano01:32.log acano01:31.log passwdacano01:29.log acano01:33.log xstartupfirst : which x i take and if it don't care to take any of themfor EX if i use x=28second :when i run vnc viewer in my machine i use address get connection closed unexpectedlynote i run vnc viewer after i connect VPN client and F-Securethanks for help in advance

Have you tried setting up the tunnel with Putty instead of F-secure? Do you get similar "connection closed" using Putty?

i.e. using 28 as the example:

a) Configure PuTTY

PuTTY -> Configuration -> SSH -> Tunnels

Source Port: 55928

Destination: acano01:5928

When you make these changes, dont forget to ADD then SAVE this PuTTY profile.

b) Configure F-Secure

If you use F-Secure instead of PuTTY, youll need to add a new Local Forwardings, thus:

F-Secure -> Profiles -> Edit Profiles -> Local Forwardings -> Add

Source Port: 55928

Destination: acano01

Destination Port: 9528

Save this new profile

That should do it. All you have left to do is make the X connection by login-on with saved config from PuTTY or F-Secure.

I worked with Putty & VNC and it work correctlythanks for your help.

Hi all

thanks for the information jeff, it really help.

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