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The Calc server is used for remote computing. Local user accounts are provided therefore. can be accessed in 2 ways.


1 Functional Range

Use remote computing @calc for medium large operations. For small Operations use your laptop, for large ones Ivana's cluster. Coordinate with your colleagues, and use gkrellm to monitor system resources. (30% virtualisation-overhead might be indicated)

2 Backup

Your data is your responsibility, since this server is not part of a BACKUP routine. Transfer your data (e.g. code and time-series) back onto your laptop or onto your share of our Institutsserver.)

3 Access

3.1 via Direct Access

3.1.1 Prerequisites

  1. VPN client (no need within VLAN-168)
  2. ssh client
  3. X client

an X server is needed if graphics shall be displayed, staying in text mode you would not need it.

3.1.2 work-flow

Your console (terminal) still controls the session, so if e.g. your laptop runs short on batteries, your calculation is interrupted and lost.

  • login at the remote host
ssh -X <remote_user>

the first time you might want to check the host-keys:

a6:b2:e6:b2:69:79:03:2d:dc:a8:32:f3:9d:36:b1:e3   (ECDSA)
31:9a:05:c8:02:83:58:da:4e:3a:92:36:8c:89:29:c4   (RSA)
  • make your data available
    • either by running a script to connect your vladimir-data

(only if you have got an account at the institutsserver, i.e. being staff)

mount_vladimir <vladimir_user>
  • or some secure-copy transfers
scp -r <my_local_data> <remote_user>
  • start your calculations, e.g
  • transfer your outcome and delete your original data (if you don't use it any more)

or disconnect from vladimir


3.2 via Virtual Desktop


you can use a virtual desktop to login the calc server.

  1. F5 for connecting to the UNI-VPN
  2. vncviewer to connect to your Desktop

3.3 via sftp and WEB-R

  1. F5 for connecting to the UNI-VPN
  2. sftp (e.g. FileZilla) to upload your workspace
  3. to do your R

3.3.1 Prerequisites

  • VPN client (can be omitted within VLAN-168)
  • vnc-client like tigervnc (former tight-vnc)
yum install tigervnc or apt-get install tigervnc-viewer
or similar viewers for windows, etc.


  • java enabled web-browser to run an unsigned applet (which normally causes troubles)

3.3.2 work-flow

  1. Establish a VPN tunnel to begin with.
    Make sure to be within the VPN university subnet.
  2. start your vnc-client

(Technically, connecting through a virtual desktop another username/password pair would be necessary.) Your username is mapped to the port:=5900+<Display> number, your password is just the same anyway.)


or - even better tunnel the session through ssh

vncviewer -via <remote-user> localhost:port

Best to use the Full-Screen-Mode, note the keys how to escape, e.g. <Strg> + <Alt> + <Shift> + <F> Don't forget to close the vncviewer before opening it at another host to get the geometry-settings right. Some viewers like viagre disable sending special keys by default (<Strg>+<Q> in this case). Make sure to enable them, just not to get locked out in FullScreen mode.

If you use a java-enabled web-browser and allow an unsigned applet to run, calculate your Port := 5800+<Display>

Use your Virtual Linux Desktop's terminal (e.g. gnome-terminal) and continue as described in 1). Start your calculation and close the viewer. Within the VPN uni-subnet or VLAN-168 you can re-open a viewer and continue.

3.3.3 Bugs

Avoid switching to full-screen, because vnc might get into troubles.

3.4 Applications

3.4.1 Matlab

Open a terminal via e.g. Application > Favorites > Terminal. At the command-prompt put in matlab. After the licensing server is asked for authorization the GUI starts up. Don't close this terminal, since it's the controlling terminal for Matlab. Alternatively press <Alt>+<F2> and fill in matlab. You can also use matlab in text mode from the command line.

3.4.2 R studio

edit R source files in some text-editor and run it afterwards, or use rstudio. you might also want to secure-copy files in your server share and run R-studio in a web browser:

3.4.3 Python

some python-libs for finance have been installed on request.

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