Differences

This shows you the differences between two versions of the page.

--- en:praktikum:zugang [2024/10/09 10:15] – [Logging in via Remote Desktop Protocol] rhainich
+++ en:praktikum:zugang [2025/10/30 15:40] (current) – [Alternative: Xpra] rhainich
@@ Line 1: / Line 1: @@
 ====== Access to the laboratory computer ======
+<WRAP center round info 60%>
+From December 2024, to access the data reduction computer via SSH, you must first log in via VPN. The [[https://www.uni-potsdam.de/en/zim/angebote-loesungen/vpn | ZIM]] explains how to set up the VPN. Unfortunately the instructions are only available in German. If you have any questions about the VPN, please contact ZIM directly.
+</WRAP>
 {{section>deng:praktikum:a12:status#Laboratory computer&noheader}}
-The analysis of the data obtained within the scope of the laboratory courses can either be done from your computer at home or directly at our laboratory computer after previous date arrangement.
+There are two ways to analyse the data collected during the placement: 1. you can carry out the analysis directly on the computer called //columba// at our university by prior arrangement or 2. you can log on to this computer from your home computer and then carry out the data analysis from home.
 ===== External Login =====
-The remote analysis of the data can be done in the computer pool at the physic institute or at your home computer with internet access.
+The data can also be analysed remotely, both from the physics institute's computer pool and from a home computer with an internet connection. There are several ways of accessing the data, each with its own advantages and disadvantages. Credentials can be obtained from the supervisors or will be announced by email after the introduction:
    User:      alpha
    Password:  is given in the seminar
-**alpha** is given here as an example and must be replaced by the corresponding group name. The password can also be obtained from the supervisors.
+**alpha** is given here as an example and must be replaced by the corresponding group name.
 ==== Linux / Unix ====
@@ Line 28: / Line 30: @@
 Alternatively you can log in with [[https://www.xpra.org/|Xpra]], which also communicates via //SSH//, but allows you to work with graphical output even with a poor internet connection. //Xpra// usually has to be installed from the package sources first. Once this is done, the following command establishes a connection to the laboratory computer
-   xpra start ssh:alpha@columba.astro.physik.uni-potsdam.de --ssh=ssh
+   xpra seamless ssh:alpha@columba.astro.physik.uni-potsdam.de --start=konsole
 The command is not very different from the one above, except that here the beginning and the end are slightly different. **alpha** has to be replaced by the group name here as well. If the connection has been established successfully, a //Xpra// icon or menu usually appears on the desktop (under Ubuntu it can be found in the upper right corner next to the network/volume/battery indicator). This menu can be used to configure //Xpra// as well as, via the menu item ''Start'', to start programs directly on the laboratory computer. //Xpra// has the nice advantage that the windows integrate seamlessly into the local system.
-Furthermore it offers the possibility to disconnect from the //Xpra// session without ending it by using the menu button ''Disconnect''. This allows you to interrupt the session at any point and continue it later. All that is needed is the following console command:
+Furthermore it offers the possibility to disconnect from the //Xpra// session without ending it by typing ''xpra detach'' in a Terminal. This allows you to interrupt the session at any point and continue it later. All that is needed is the following console command:
-   xpra attach ssh:alpha@columba.astro.physik.uni-potsdam.de --ssh=ssh
+   xpra attach ssh:alpha@columba.astro.physik.uni-potsdam.de
 The //Xpra// session is terminated with:
@@ Line 73: / Line 75: @@
 In addition to the above mentioned possibilities, a //X2Go// server is also installed on the laboratory computer **columba**, which allows to work remotely and efficiently with graphical programs. The //X2Go// client is available for all major operating systems (Windows, Linux and MacOS).
-{{ :ost:software:x2go_1.png?direct&400 |}}
+{{ :ost:software:x2go_main_window.png?direct&400 |}}
 After installing the client you can create a new session by clicking **Session** and then **New session ...**. In the window that opens you have to define the session parameters.
@@ Line 79: / Line 81: @@
 <WRAP group>
 <WRAP half column>
-{{ :ost:software:x2go_2.png |}}
+{{ :ost:software:x2go_new_session.png |}}
 </WRAP>
 <WRAP half column>
-{{ :ost:software:x2go_3.png |}}
+{{ :ost:software:x2go_main_settings.png |}}
 </WRAP>
 </WRAP>
-{{ :ost:software:x2go_4.png|}}
+<WRAP group>
+<WRAP half column>
+These include **session name**, **host**, **login**, and the **session type**. The **Session name** can be freely chosen and is only used to distinguish between different sessions. As **host** ''columba.astro.physik.uni-potsdam.de'' must be specified. As **Login** the respective user name like e.g. alpha has to be entered.
-These include **session name**, **host**, **login**, and the **session type**. The **Session name** can be freely chosen and is only used to distinguish between different sessions. As **host** ''columba.astro.physik.uni-potsdam.de'' must be specified. As **Login** the respective user name like e.g. alpha has to be entered. For **Session type** you have to select ''Custom desktop'' from the dropdown menu and enter ''MATE'' as **Command**.
+The next step is to go to the ''Input/Output'' tab. Here you can enable **Fullscreen** and disable **Set Display DPI** to connect in full screen without pixelation. However, this may affect the speed of the connection.
 After clicking on ''OK'' you can start the connection to **columba** by double clicking on the corresponding session entry in the main window of //X2Go//. Only the password for the respective account will be requested before the connection is established. The window that opens shows the MATE desktop, on which you can work as if you were sitting directly at the computer.
+{{ :ost:software:x2go_4.png |}}
+</WRAP>
+<WRAP half column>
+{{ :ost:software:x2go_input-output_settings.png |}}
+</WRAP>
+</WRAP>
 <fc #ff0000>Attention Wayland users:</fc> Under Wayland, it is possible that the current client does not work properly and simply crashes when logging in, in this case it may help to start the client from the command line with